Electronic architecture for intravascular ultrasound technology

Abstract

Systems and methods for imaging, such as with an intravascular ultrasound (IVUS) imaging device, are employed with components and electronic architecture for generating high image quality with, for example, rotational IVUS with extended catheter lengths. Filtering signals may be used to improve imaging clarity and utility for real time measurements of luminal anatomy, such as vasculature. Workflow may be facilitated by hands-free commands, voice control, and gestures. Artificial intelligence and machine learning aspects along with real time measurements of blood flow and border detection and reduction of non-uniform rotational distortion (NURD) are provided.

Description

EVID.049WO PATENT ELECTRONIC ARCHITECTURE FOR INTRAVASCULAR ULTRASOUND TECHNOLOGY REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.63 / 632,966 filed April 11, 2024 titled “Electronic Architecture For Intravascular Ultrasound Technology” which is hereby incorporated by reference in its entirety, herein. BACKGROUND Field

[0002] The present disclosure relates to the field of imaging vessels, blood, and other target tissue, using, for example, ultrasound. Intravascular ultrasound (IVUS), peripheral, neurovascular and coronary imaging, as well as ultrasound visualization outside a vessel, are provided in several embodiments. Imaging is used to facilitate intervention in several embodiments. Description of the Related Art

[0003] Ultrasound imaging systems, including those used for intravascular imaging, transmit and receive acoustic waves in order to produce an image based off reflections from objects near the ultrasound transducer, such as blood, healthy tissue, and diseased tissue. IVUS catheter systems can be used to capture ultrasound images. SUMMARY

[0004] Several embodiments of medical imaging systems, such as IVUS systems are provided herein. In various embodiments, an IVUS system is provided that (1) is easy to setup with less time-consuming steps, (2) provides a device such as a catheter that is easy to connect and manually manipulate, and / or (3) has high image quality that supports efficient image interpretation. Advantageously, according to several embodiments, such systems include one or more features that, for example, enhance imaging, image guided therapy, measurements, usability, ease of setup, streamlining of workflow, reduced operating times, improved clinical efficacy, accuracy of therapeutic intervention delivery, guiding interventional therapy, synergies with peripheral interventions, informing treatment decisions, optimizing the user experience throughout the clinical workflow including setup, imaging, measurements and reporting, and diagnosis accuracy among others. The IVUS systems and methods described herein may be used for enhanced imaging in peripheral, coronary and neurovascular vessels, as well as to facilitate therapeutic intervention in such vessels.

[0005] In several embodiments, IVUS systems and methods involve technical components and electronic architecture for generating high image quality with rotational IVUS with extended catheter lengths (e.g., IVUS devices with an extended and more useable length, torquable catheter to provide for high image quality rotational IVUS, multilayer cable tubes, reduction of non-uniform rotational distortion (NURD), ultrasound control board(s) for catheter interface module(s) with converters, multiplexers, and / or field-programmable gate arrays for receiving, decoding, andanalyzing ultrasonic signals. In various embodiments, streamlining of workflow and ease of setup and use is enhanced via hands-free commands, voice control, and / or gestures are be used to interact with the imaging systems (e.g., IVUS system) in some embodiments. Artificial intelligence and / or machine learning (AI / ML) are employed in some embodiments to enable image interpretation, (e.g., based on real-time detection, classification, and / or measurements of image features such that the processing of images occurs more quickly and such that an amount of image information is increased, more accurate, or provided with increased confidence and / or displayed with enhanced confidence indicators), streamline workflows, increase ease of setup, increase processing efficiency, broaden IVUS adoption, analyze images, identify vascular irregularities, conduct measurements, support diagnoses, predict outcomes or provide treatment recommendations, facilitate intervention and / or confirm progress of or success of a treatment. In several embodiments, irregularities may be identified across an image series and displayed graphically as an overlay on the timeline or schematic representation of the patient’s anatomy.

[0006] In several embodiments, systems and methods for obtaining ultrasound images are provided. In some embodiments, one or more transducers is provided along with a workstation. In some embodiments, provided is an imaging core comprising a transducer that is disposed (e.g., contained within, housed, etc.) in a device (such as a catheter body, probe, scope, etc.) and an imaging core cable configured to rotate the transducer. The workstation, according to several embodiments, comprises one or more controller, circuitry, processor, memory, storage, input(s) and / or output(s). For example, the systems are configured for transmitting different signals at elevated bit rates and receiving corresponding backscattered signals and filtering the a waveform based on a characteristic to generate images. The systems and methods are used, in several embodiments, to visualize blood vessels, lumens, and other structures, and can be optionally used to facilitate therapy.

[0007] In several embodiments, transducer and / or catheter system are provided independently of the workstation. Likewise, the workstation may be provided independently of the transducer and / or catheter system. Several embodiments are modular in that they can be seamlessly integrated into existing infrastructure and equipment.

[0008] In some embodiments, one or more elements of the workstation described herein can be incorporated into the catheter system, probe, scope, etc.

[0009] In some embodiments, the workstation comprises a controller (e.g., processor, circuitry, input(s), output(s), etc. for controlling electronics) configured to generate two or more digital transmit signals at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits (e.g., 10, 12, 14, 16, 18, 20 bits and other values and ranges therein). The two or more digital transmit signals may include at least a first transmit waveform and a second transmit waveform, wherein the first transmit waveform is longer than the second transmit waveform, wherein at least one of the first transmit waveform and the second transmit waveform comprises coded phases that are nonlinear with time. In one embodiment, a waveform is longer by having a longer duration (e.g., longer time, so for example, if waveforms have the same wavelength, it longer will have more cycles. In several embodiments, having a longer waveform between uncoded as compared to coded is longer in time. For example, inseveral embodiments, waveforms may be coded that have nonlinear phase with time. In several embodiments, the phases may be coded in that waveform design(s) can be unique coded excitation designs with broader spectral bandwidths where received echoes are decoded after using coded transmit waveforms. These coded designs can maintain the high axial spatial resolution for all deeper depths in the image, providing greater penetration as the energy in the transmitted waveforms is significantly greater with broad / wide received spectral bandwidth. In some embodiments, the coded designs can trade-off some penetration and select a fixed spectral content at higher frequencies. In one embodiment, spectral bandwidths and / or spectral content is not used. The controller may be configured to receive a plurality of backscattered signals from the transducer at a receive bit rate of at least 200 Msps and / when at a receive bit depth of at least 12 bits, wherein a receive signal comprises the plurality of backscattered signals. The controller may be configured to filter the plurality of backscattered signals based on one or more characteristics of the at least one of the first transmit waveform and the second transmit waveform, wherein at least one of the plurality of backscattered signals is filtered with a decoding filter for the at least one of the first transmit waveform and the second transmit waveform that comprises coded phases that are nonlinear with time. In one embodiment, a sequencer controller may be configured to temporally interleave the two or more digital transmit signals and the plurality of backscattered signals and combine the filtered plurality of backscattered signals into single lines of an image. The controller may be configured to generate an ultrasound image (such as an IVUS or other image) based on a plurality of the single lines of the image. The system may also include an ultrasound control board comprising: a digital-to-analog converter configured to convert the two or more digital transmit signals to analog; and an analog-to- digital converter configured to convert the receive signal from the transducer to digital. The system may also include an interface (such as a probe, scope or catheter interface module) configured to be placed in at least one of a mechanical and electrical communication with the imaging core. The system may also include a system cable configured to connect the interface module to the workstation.

[0010] In several embodiments, the accumulated imaging time is about 5 seconds to several hours (e.g., 5, 10, 30, 60 seconds, 2, 5, 10, 20, 30, 60 minutes, and 2 – 10 hours or more, including values and ranges therein). The receive and transmit rates are at least 200 Msps megasamples per second (200,250, 300, 400, 500, 600, 700, 750, 800, 900, 1000 Msps or more).

[0011] Although shorter catheter bodies are provided in several embodiments, in one embodiment, the catheter body has a length of at least 177 centimeters, with a working length portion (e.g., portion of the catheter that is inserted into a patient) of at least 90 centimeters; and a proximal extension (e.g., portion of a catheter that may be mechanically coupled to the working length portion, that can extend an overall length of a catheter, such as to move a catheter interface module out of a sterile field.) having a length of at least 1 centimeter. For example, in one embodiment, the total length is 177-210 cm of which 90-210 cm is the working length and the proximal extension is 1- 120 cm. The lengths are advantageous in some embodiments because longer working length portions allow for fartheraccess into a patient’s body from an access point, and longer overall lengths can provide easier accessibility and can move a catheter interface module (e.g., with motor, etc.) farther away and outside of patient sterile field.

[0012] The transducer, in some embodiments, comprises one or a combination of the following: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal. Multiple transducers are provided in some embodiments.

[0013] In one embodiment, an interface module is provided that provides connection to mechanical control and / or electrical control and power to probes, scopes, and other devices. The interface module may be catheter interface module or an interface module for probes, scopes, and other devices. The interface module may include a linear high-power transmit amplifier configured to amplify the two or more digital transmit signals. In some embodiments, the interface module may include a selectable impedance matching module configured to transform an impedance of the linear high-power transmit amplifier to match an input impedance of a signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; and / or a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal.

[0014] In one embodiment, at least one of the first transmit waveform and the second transmit waveform has coded instantaneous frequencies versus time that are nonlinear with time. In one embodiment, at least one of the first transmit waveform and the second transmit waveform has coded instantaneous frequencies versus time that are linear with time. The coded phases may include one or more changes to an amplitude and a phase for a frequency component in a transmit pulse to generate a broader bandwidth transmit pulse.

[0015] In various embodiments, the systems and methods described herein (e.g., the workstation) have one or several of the following advantageous capabilities: (i)operate under voice control, (ii) use an artificial intelligence algorithm(s) identify a vessel border, (iii) determine blood flow proximate to the catheter body, probe, scope or other device, (iv) use an artificial intelligence algorithm to identify blood or a location or a type of plaque, calcium, stent apposition, thrombus, or dissection. In one embodiment, the transducer, when placed only in a first blood vessel advantageously provides visualization of both said first blood vessel and a second blood vessel, thereby providing visualization of both the first and second blood vessels simultaneously and in real time.

[0016] The controller, according to several embodiments, comprises one, two or more processors configured to transmit signals at a bit depth of at least 10 bits. The interface module (e.g., catheter interface module) may include a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the ultrasound transducer. In one embodiment, the catheter interface module may include a slip ring with a non-electrically- conductive coupling shaft connected to the slip ring, The workstation may combine the receive signal from at least one of the first transmit waveform and the second transmit waveform into the single image line through replacing a rangeof echoes from one line with backscattered echoes from another line. The workstation may combine the receive signal from at least one of the first transmit waveform and the second transmit waveform into the single image line through replacing a range of echoes from one line with a blended combination of echoes from the plurality of the single lines of the image. In one embodiment, the workstation may combine receive echoes from two or more different transmit waveforms into the single image line through replacing a range of echoes after linearly interpolating analytically between two lines over a same distance. The system cable may include a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and wherein the system cable is configured for multiple time-interleaved functions per shielded twisted pairs (STP).

[0017] The interface module (e.g., catheter interface module) may be configured to be placed outside of a sterile field. The interface module may include a motor and a motor control module configured to monitor a position of the motor.

[0018] The system may include a non-volatile electronic memory configured to store at least one of a part number, an identification, usage monitoring, a security copy protection, and catheter-specific acoustic data retrieval. The system may include a precise motor control configured for improving image visual stability and enabling line density control for subsections within a 360 degree image.

[0019] The system may be configured for reduction of non-uniform rotational distortion (NURD). The digital-to-analog converter may be high-fidelity and the analog-to-digital converter is oversampled. In various embodiments, the system may be configured to: automatically calculate one or more measurements of a vascular lumen from an IVUS image imaged by the imaging core, automatically identify an edge of the vascular lumen; calculate one or more confidence values associated with one or more sections of the edge of the vascular lumen; and / or provide a graphical representation of the edge of the vascular lumen to be displayed in real time as an overlay on the IVUS image, wherein the graphical representation of the edge of the vascular lumen is divided into the one or more sections of the edge of the vascular lumen based on the one or more confidence values associated with each of the one or more sections of the edge of the vascular lumen. The system may be configured for image analysis using an artificial intelligence algorithm to identify at least one of a vessel lumen and a vessel border. The system may be configured for image analysis using an artificial intelligence algorithm to identify blood or a location or a type of at least one of plaque, thrombus, calcium, lesion, and vessel dissection in tissue such as a peripheral, neurovascular or coronary vascular system. Tissue and structural abnormalities are visualized in several embodiments. Placement and / or positioning of stents, valves and other medical devices can also be advantageously guided with the imaging systems described herein. The imaging technologies described herein may also be used to facilitate therapies. Advantageously, improved diagnosis using the enhanced imaging techniques provided here may also efficiently and cost-effectively help guide or inform whether certain patients would be candidates for particular therapeutic interventions or further diagnostics,

[0020] In various embodiments, provided is an ultrasound imaging system (such as an IVUS, intra- luminal system, etc.) that comprises a workstation with a controller configured to: generate two or more digital transmit signals at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits, the two or more digital transmit signals comprising at least a first transmit waveform and a second transmit waveform, wherein the first transmit waveform is longer than the second transmit waveform, wherein at least one of the first transmit waveform and the second transmit waveform comprises coded phases that are nonlinear with time; receive a plurality of backscattered signals from the transducer at a receive bit rate of at least 200 Msps and / when at a receive bit depth of at least 12 bits, wherein a receive signal comprises the plurality of backscattered signals; filter the plurality of backscatter signals based on one or more characteristics of the at least one of the first transmit waveform and the second transmit waveform, wherein at least one of the plurality of backscatter signals is filtered with a decoding filter for the at least one of the first transmit waveform and the second transmit waveform that comprises coded phases that are nonlinear with time; a sequencer controller to temporally interleave the two or more digital transmit signals and the plurality of backscattered signals and combine the filtered plurality of backscattered signals into single lines of an image; and / or generate an image (e.g., an IVUS, intra-luminal, or other images) based on a plurality of the single lines of the image. The system may include an ultrasound control board comprising: a digital-to-analog converter configured to convert the two or more digital transmit signals to analog; and an analog-to-digital converter configured to convert the receive signal from the transducer to digital.

[0021] In various embodiments, provided is a system (such as a catheter system, an IVUS catheter system, intra-luminal system, scope, etc.) that comprises an interface module comprising a linear high-power transmit amplifier configured to amplify two or more digital transmit signals; a selectable impedance matching module configured to transform an impedance of the linear high-power transmit amplifier to match an input impedance of a signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and / or instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal. In one embodiment, the interface module is a catheter interface module. In several embodiments, an IVUS catheter system may include a catheter body having a length (e.g., of at least 177 centimeters), the catheter body comprising: a lumen; a working length portion having a length (e.g., of at least 90 centimeters); and a proximal extension having a length (e.g., of at least 1 centimeter); an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an imaging electrical core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to generate a digital high speed, high bit count transmit signal; and an ultrasound control board comprising a high-fidelity digital-analog converter configured to convert the transmit signal to analog; a catheter interface module configured to be placed in electrical communication with the imaging core via the imaging electrical core wire, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a system cable configured to connect the catheter interface module to the workstation.

[0022] In one embodiment the distal working length portion of the catheter has a range of 90 – 210 centimeters in length and the proximal extension has a range of 1 – 120 centimeters in length. The controller may be configured to generate the transmit signals at a bit rate greater than or equal to 200 megasamples per second (Msps). The at least one processor may be configured to transmit the signals at a bit depth (e.g., of at least 10 bits, 14 bits, etc.). The system cable may include a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time- interleaved functions per STP inner cable (e.g., digital and analog). The catheter interface module may be configured to be placed outside of a sterile field. The catheter interface module may be configured to be placed inside of a sterile field, such as within a sterile bag.

[0023] In several embodiments, a catheter interface module configured to be placed in mechanical and electrical communication with the imaging core via the imaging electrical core wire and the workstation, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a selectable impedance matching module configured to transform an electrical impedance of the transmit amplifier to match an input impedance of the signal path to the imaging core; and a system cable configured to connect the catheter interface module to the workstation.

[0024] The catheter interface module may include a motor and a motor control module configured to monitor a position of the motor. A non-volatile electronic memory may be configured to store part number, identification, usage monitoring, security (e.g., copy protection), and / or catheter-specific acoustic data retrieval. In one embodiment, a precise motor control may be configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image.

[0025] In several embodiments, an intravascular ultrasound (IVUS) catheter system may include a workstation that may comprise a controller configured to: generate a digital transmit signal at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits; and receive a receive signal from the transducer at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits; an ultrasound control board comprising: a high-fidelity digital-to-analog converter configured to convert the transmit signal to analog; and an oversampled analog-to-digital converter configured to convert the receive signal from the transducer to digital. In several embodiments, a catheter interface module may be configured to be placed in mechanical and electrical communication with the imaging core via the imaging electrical core wire and the workstation, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match the inputimpedance of the signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre- programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal. In one embodiment, the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the ultrasound transducer.

[0026] In several embodiments, a workstation may include a controller configured to: generate two or more digital transmit signals each at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits, the transmit signals comprising a plurality of two different waveforms one longer than the other, one with more transmitted energy than the other; receive backscattered signals from the transducer at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits, the receive signal comprising a plurality of backscatter signals; filter the plurality of backscatter signals based on one or more characteristics of the plurality of different transmit waveforms; a sequencer controller to temporally interleave paired transmit and receive events and combine pairs of filtered backscattered echoes into single lines of an image; and generate an IVUS image based on the plurality of image lines. In several embodiments, the catheter interface module may include a linear high-power transmit amplifier configured to amplify the transmit signal; a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal.

[0027] In various embodiments, the workstation may combine the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes from one line with the receive echoes from another line. The workstation may combine the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes from one line with a blended combination of echoes from the two or more lines. The workstation may combine the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes after linearly interpolating analytically between two lines over the same distances.

[0028] In several embodiments, an intravascular ultrasound (IVUS) catheter system may include a workstation comprising: a controller configured to: generate two or more digital transmit signals each at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits, the transmit signals comprising a plurality of two different waveforms one longer than the other and one with coded phases that are nonlinear with time; receive backscattered signals from the transducer at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits, the receive signal comprising a plurality of backscatter signals; filter the plurality ofbackscatter signals based on one or more characteristics of the plurality of different transmit waveforms, one with a decoding filter for the coded transmit signals; a sequencer controller to temporally interleave paired transmit and receive events and combine the pairs of filtered backscattered echoes into single lines of an image; and generate an IVUS image based on the plurality of image lines.

[0029] In various embodiments, the two or more different waveforms in the controller are different where one is longer than the other and one has coded instantaneous frequencies versus time that are nonlinear with time. The two or more different waveforms in the controller may be different where one is longer than the other and one has coded instantaneous frequencies versus time that are linear with time.

[0030] In several embodiments, the system is configured for reduction of non-uniform rotational distortion (NURD). In several embodiments, the system is configured to: automatically calculate one or more measurements of a vascular lumen from an IVUS image imaged by the imaging core, automatically identify an edge of the vascular lumen; calculate one or more confidence values associated with one or more sections of the edge of the vascular lumen; and / or provide a graphical representation of the edge of the vascular lumen to be displayed in real time as an overlay on the IVUS image, wherein the graphical representation of the edge of the vascular lumen is divided into the one or more sections of the edge of the vascular lumen based on the one or more confidence values associated with each of the one or more sections of the edge of the vascular lumen. In several embodiments, the system is configured for image analysis using an artificial intelligence algorithm to identify at least one of a vessel lumen and a vessel border. In several embodiments, the system is configured for image analysis using an artificial intelligence algorithm to identify blood or a location or a type of at least one of plaque, thrombus, calcium, and vessel dissection in a peripheral vascular system.

[0031] In several embodiments, an intravascular ultrasound (IVUS) catheter system may include a catheter body comprising a lumen; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer, a cable configured to rotate the transducer, the cable comprising a proximal portion, a distal portion, and a connector hub configured to connect the proximal portion and the distal portion; and an electrical wire; a catheter interface module configured to be placed in mechanical and electrical communication with the imaging core, the catheter interface module comprising: a controller configured to transmit high speed, high bit count transmit signals; a high-fidelity digital-to-analog converter configured to convert the transmit signals to an analog transmit signal; and a linear high-power transmit amplifier configured to amplify the analog transmit signal; and a cable configured to place the catheter interface module in electrical contact with an ultrasound control board.

[0032] In several embodiments, an intravascular ultrasound (IVUS) catheter system may include a catheter body comprising a lumen; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer, an imaging core cable configured to rotate the transducer; and an imaging electrical core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to generate a digital high speed, high bit count transmit signal; and an ultrasound control board comprisinga high-fidelity digital-to-analog converter configured to convert the transmit signal to analog; a catheter interface module configured to be placed in electrical communication with the imaging core via the imaging electrical core wire, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a system cable configured to connect the catheter interface module to the workstation.

[0033] In several embodiments, an intravascular ultrasound (IVUS) catheter system may include a catheter body comprising a lumen; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer, an imaging core cable configured to rotate the transducer; and an imaging coaxial core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to generate a digital high speed, high bit count transmit signal; and an ultrasound control board comprising a high- fidelity digital-to-analog converter configured to convert the transmit signal to analog; a catheter interface module configured to be placed in electrical communication with the imaging core via the imaging electrical core wire, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a system cable configured to connect the catheter interface module to the workstation.

[0034] In several embodiments, a catheter interface module may include a linear high-power transmit amplifier configured to amplify a transmit signal; and a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core, wherein the catheter interface module configured to be placed in mechanical and electrical communication with an imaging core and a workstation.

[0035] The catheter interface module may include at least one of the following: a controller configured to generate a digital high speed, high bit count transmit signal; and / or a high-fidelity digital-to-analog converter configured to convert the transmit signals to analog.

[0036] In several embodiments, a method for intravascular ultrasound (IVUS) imaging may include providing an IVUS catheter having a length (e.g., of at least 177 centimeters), the IVUS catheter comprising: a lumen; a working length portion (e.g., having a length of at least 90 centimeters); a proximal extension having a length (e.g., of at least 1 centimeter); a transducer disposed within the lumen; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal; and converting the digital transmit signal to analog using a high fidelity digital-to-analog converter; and amplifying the transmit signal using a linear high- power transmit amplifier.

[0037] In various embodiments, the working length portion of the IVUS catheter is between about 90 centimeters and about 210 centimeters in length, and wherein the proximal extension of the IVUS catheter is between about 1 centimeter and about 120 centimeters in length. Generating the transmit signal may include generating the transmit signal at a bit rate greater than or equal to 200 megasamples per second (Msps). Generating the transmitsignal may include generating the transmit signal at a bit depth of at least 14 bits and / or at least 10 bits. The system cable may have a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable (e.g., digital and analog). The catheter interface module may be configured to be placed outside of a sterile field. The catheter interface module may be configured to be placed inside of a sterile field, such as within a sterile bag.

[0038] In several embodiments, a method for intravascular ultrasound (IVUS) imaging may include providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal; and converting the digital transmit signal to analog using a high fidelity digital-to-analog converter; amplifying the transmit signal using a linear high-power transmit amplifier; and transforming an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core.

[0039] In various embodiments, the IVUS catheter comprises a length of at least 177 centimeters. The IVUS catheter may include a working length portion having a length between about 90 centimeters and about 210 centimeters and a proximal extension having a length between about 1 centimeter and about 120 centimeters. Generating the transmit signal may include generating the transmit signal at a bit rate greater than or equal to 200 megasamples per second (Msps). Generating the transmit signal may include generating the transmit signal at a bit depth of at least 14 bits and / or at least 10 bits. The system cable may include a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable (e.g., digital and analog). The catheter interface module may be configured to be placed outside of a sterile field. The catheter interface module may be configured to be placed inside of a sterile field, such as within a sterile bag. The catheter interface module may include a motor and a motor control module, and wherein the method further comprises monitoring a position of the motor.

[0040] In several embodiments, a method for intravascular ultrasound (IVUS) imaging may include providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal at a transmit bit rate of at least 200 Megasamples per second (Msps) and a transmit bit depth of at least 10 bits; converting the digital transmit signal to analog using a high fidelity digital-to-analog converter; amplifying the transmit signal using a linear high-power transmit amplifier; transforming an impedance of the transmit amplifier to match the inputimpedance of the signal path to the imaging core; producing at least one pulse-echo from the transducer based on the transmit signal; receiving, at the transducer, a receive signal at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits; converting the receive signal from analog to digital via an oversampled analog-to-digital converter; amplifying the receive signal via a low noise amplifier; creating, via a field programmable gate array, a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and applying the time gain compensation profile to the receive signal via a variable gain amplifier.

[0041] In several embodiments, a method for intravascular ultrasound (IVUS) imaging may include providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal at a transmit bit rate of at least 200 Megasamples per second (Msps) and a transmit bit depth of at least 10 bits, wherein the transmit signal comprises a plurality of coded waveforms; converting the digital transmit signal to analog using a high fidelity digital-to-analog converter; amplifying the transmit signal using a linear high-power transmit amplifier; transforming an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core; producing at least one pulse-echo from the transducer based on the transmit signal; receiving, at the transducer, a receive signal at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits, wherein the receive signal comprising a plurality of backscatter signals; converting the receive signal from analog to digital via an oversampled analog-to-digital converter; amplifying the receive signal via a low noise amplifier; creating, via a field programmable gate array, a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; applying the time gain compensation profile to the receive signal via a variable gain amplifier; filtering the plurality of backscatter signals based on one or more characteristics of the one or more coded waveforms; decoding the plurality of backscatter signals based on the one or more characteristics of the one or more coded waveforms to generate a plurality of image lines; and generating an IVUS image based on the plurality of image lines.

[0042] In several embodiments, a method for intravascular ultrasound (IVUS) imaging may include providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen; an imaging core cable configured to rotate the transducer, the cable comprising a proximal portion, a distal portion, and a connector hub configured to connect the proximal portion and the distal portion; and a wire; providing a catheter interface module, the catheter interface module configured to be placed in mechanical and electrical communication with the transducer; connecting the catheter interface module and the IVUS catheter in electrical communication with an ultrasound system control board via a system cable; generating, via a controller, a high speed, high bit count signals; converting thetransmit signals from digital to analog via a high fidelity digital-to-analog converter; and amplifying the signals via a linear high-power transmit amplifier.

[0043] In several embodiments, a method of facilitating signal transmission along a device that would otherwise cause distortion may include processing for high speed signals, converting the high speed signals from digital to analog, and / or amplifying the high speed signals with a high-power transmit amplifier.

[0044] In several embodiments, a kit including one or more of the catheters, hubs, seals, plugs as described herein is provided along with instructions for use.

[0045] In several embodiments, a use of any of the devices, systems and methods herein may be used: (i) for imaging without any therapy, (ii) for imaging before, after or simultaneously with using ultrasound as a therapy on the same or different system, (iii) for imaging a non-vessel lumen, cavity or organ, (iv) for imaging before, after and / or simultaneously with using non-ultrasound technology as a therapy, wherein said non-ultrasound technology comprises mechanical thrombectomy and / or an interventional coronary procedure, (v) for minimally-invasive imaging, (vi) for imaging of intravascular tissue for identifying irregularities, disease, and / or injury for medical treatment, (vii) for identification of lesions, plaque, thrombus, calcium buildup, dissections, and measurement of these abnormalities, (viii) with a non-volatile electronic memory configured to store part number, identification, usage monitoring, security (copy protection), and / or catheter-specific acoustic data retrieval, (ix) with a precise motor control configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image, and / or (x) for image analysis using an artificial intelligence algorithm to identify a tissue border, plaque, calcium, thrombus, dissection, and / or stent apposition (including stent malapposition). When imaging non-vessels, in some embodiments, it should be understood that the term “IVUS catheter” can be replaced herein with ultrasound imaging device. For example, probes, transducers, scopes, wands, etc., may be used instead of or in addition to catheters. Many innovative features described herein are also suitable for externally delivered ultrasound.

[0046] In some embodiments, IVUS is a diagnostic image-guided therapy-tool for the treatment of both peripheral arterial and venous disease, enabling 2D and / or 3D intraluminal visualization. In some embodiments, IVUS (or other imaging devices) are provided in combination with components and accessories such as a catheter, a catheter interface module, and / or a controller. In various embodiments, streamlining of workflow and ease of setup and use is enhanced via hands-free commands, voice control, and / or gestures are used to interact with the imaging systems (e.g., IVUS system). Artificial intelligence and / or machine learning (AI / ML) are employed in some embodiments to enable image interpretation, streamline workflows, increase ease of setup, increase processing efficiency, broaden IVUS adoption, analyze images, identify vascular irregularities, conduct measurements, support diagnoses, facilitate intervention and / or confirm progress of or success of a treatment. In several embodiments, irregularities may be identified across an image series and displayed graphically as an overlay on the timeline or schematic representation of the patient’s anatomy. In one embodiment, the system is matched for high definition, ultra high definition, high definition plus (e.g., HD, UHD, HD+, etc.) image quality using acoustics and signal processing customized for peripheralvascular imaging with superior resolution and optimal penetration. Several embodiments are configured for intravascular imaging with a platform that is optimized for peripheral vascular and / or coronary procedures that will enable improved image interpretation, intervention guidance, and enhance ease of use and improve overall usability to streamline intraprocedural and clinical workflow. In several embodiments, the system improves usability with a contemporary system featuring a simplified user-interface and enhanced total-system capabilities leveraging AI to streamline workflow and image interpretation. In various embodiments, catheters, devices, systems, and methods may be configured for use in performing edge-based machine learning computations associated with an image or image analysis using an artificial intelligence algorithm to identify a tissue border, plaque, calcium, thrombus, dissection, and / or stent apposition.

[0047] For example, in various embodiments IVUS systems may be used for image interpretation and measurement of luminal geometry (e.g., diameter, stenosis, peripheral interventions, coronary interventions, atherectomy, lithotripsy, intravascular lithotripsy (IVL), balloon placement, stent placement, venous procedures, below the knee (BTK) procedures, AV Fistula, and other procedures are performed with embodiments described herein (including for example robotic and robot-controlled diagnosis and treatment devices, tools, and procedures (e.g., for precision guided robotic and / or automatic instruments for repair with small incisions in minimally invasive robotic procedures, such as robotic vascular, endovascular, cardiac and / or peripheral procedures, vessel bypass surgery, vasculature repair, robotic assisted laparoscopic surgery, implant / stent / ballon / filter placement and / or removal, etc.) and other procedures are performed with embodiments described herein. In some embodiments, imaging as described herein is used to identify and / or guide the placement of an occluder in a peripheral vessel or in coronary (or other) tissue). Procedures can be performed by interventional cardiologists, radiologists, and / or vascular surgeons in hospitals, physician offices, Office Based Labs (OBL), and / or Ambulatory Surgery Centers (ASC). In several embodiments, systems described herein can be used efficiently in the hospital and OBL / ASC without specialized clinical support. In addition, several embodiments use imaging as described herein to confirm whether a particular intervention has been successfully performed immediately after such intervention has been performed or within 12-72 hours thereafter. Such confirmation may also be used several days, weeks or months later as a way to confirm that the intervention has been accomplished as desired. In some embodiments, imaging as described herein is used to confirm whether a particular intervention is being performed according to protocol in real time. For example, the imaging may be done simultaneously with (e.g., during), before and / or after the intervention. An intervention may include therapy or other intervention such as peripheral interventions, coronary interventions, atherectomy, IVL, balloon placement, stent placement, venous procedures, BTK procedures, AV Fistula, and other procedures. Imaging can include, for example, IVUS non-coronary peripheral vessels, IVUS in coronary vessels, ultrasound, intraluminal imaging, imaging of body cavities and organs, and other imaging as described herein (and combinations thereof). In some embodiments, imaging as described herein is used to identify and / or guide the placement of an occluder in a peripheral vessel or in coronary (or other) tissue. In some embodiments, the cardiac imaging as described herein isused in intracardiac visualization (e.g., may be used instead of intracardiac echocardiography (ICE) procedures). The architectures, AI / ML technologies, edge detection, voice control, plug and play, and other aspects may be particularly useful for intracardiac imaging (and in one embodiment may be used to supplement or improve ICE techniques). In some embodiments, the dimensions of the catheter components described herein are adjusted in size for intracardiac delivery (e.g., in some cases larger than the dimensions for blood vessels).

[0048] The enhanced imaging technologies described herein in several embodiments do not rely on symptom reporting by a patient or perception of a patient's symptoms Advantageously, several innovative features described herein are beneficial because they are adapted to visualize and diagnose vascular and cardiac disease early and with greater precision in small vessels. Additionally, several embodiments described herein are useful for diagnosis of May-Thurner syndrome, a blood vessel condition that can lead to deep vein thrombosis (DVT). Smaller vessel sizes can pose difficulties in placement and positioning of stents (and other devices or interventional therapies), and several embodiments described herein are adapted to image smaller vessels and facilitate placement and positioning of stents and other devices (occluders, etc.), and facilitate or otherwise inform therapy (such as mechanical clot retrieval, aspiration, lithotripsy, angioplasty, bypass procedures, etc.). Using AI, machine learning and / or data analysis, additional embodiments described herein can be further used to correlate a patient’s risk based on the enhanced images and can further suggest that a particular therapy may be more effective to treat such conditions (or suggest that the patient should be scheduled for follow up because of an increased risk). Precise diagnosis in the treatment of fibroids and cysts, which can be accomplished in several embodiments described herein using enhanced visualization and detection of the boundaries of such fibroids and cysts (including those in the uterus, ovary and breast). This, in turn, should allow for more precise and complete removal (or other treatment) of the undesired tissue, while preserving healthy tissue. The amount of the surgical margin removed or otherwise treated may also be reduced (as compared to not using the technologies described herein) because of the precision in visualization and / or boundary detection of the fibroid or cyst.

[0049] Many of these embodiments should be particularly advantageous to ensure that patients are not receiving unnecessary additional diagnostics or interventions, which in turn provides better patient care and reduces the short-term burden on the healthcare system. In several embodiments, use of a system and AI to determine patient eligibility for further intervention (e.g., further diagnostics or therapeutics) and additionally use of the system and AI to reduce risk that patient receives unnecessary further interventions. Advantages include better patient care and reduces the short-term burden on the healthcare system. Likewise, many of these embodiments help patients receive the needed additional diagnostics or interventions they need, which in turn provides better patient outcomes and reduces the long-term burden on the healthcare system (by treating patients earlier in the disease progression timeline). In several embodiments, an IVUS system provides a contemporary IVUS platform and catheter portfolio that provides improved usability with superior image interpretation and streamlined bedside workflow at a competitive cost enabling broader adoption. In several embodiments, systems described herein leverage the power of AI to enable superiorimage interpretation and streamlined workflows, increasing adoption, driving increased market penetration and enabling improved clinical outcomes with faster, more accurate diagnosis and treatment.

[0050] In some embodiments, the ultrasound imaging technologies described herein are used to visualize fluids, whether internal or externally delivered. Drug delivery, including for example via fluid or nano particle delivery, may also be visualized. Such visualization may be helpful for confirming delivery to the desired target region, saturation, etc. in a vessel or other lumen, to a tumor or other abnormality (such as thrombus, plaque, calcium, etc.). Visualization may be before, after and / or during delivery of a drug and real-time visualization is provided in several aspects. In one embodiment, ultrasound is also used to facilitate drug delivery. Tumors include, for example, fibroids, polyps, abnormal cell clusters, etc. and may be benign or cancerous, including but not limited to those located in reproductive organs such as the uterus, the nasal or ear cavity, rectum, colon, other intestinal regions or elsewhere.

[0051] In some embodiments, the ultrasound imaging technologies described herein are used to visualize neuromodulation, such as nerve ablation, blocks, and stimulation. Such visualization may be helpful for confirming delivery of the neuromodulation (e.g., by heat, cryotherapy, chemical, radiofrequency, microwave, acoustic, etc.) to the desired target nerve(s) in a vessel, other lumen or region. This is turn may be used to increase the likelihood that the target nerve is treated, while preserving healthy nerves and other healthy tissue surrounding the target nerve. Visualization may be before, after and / or during neuromodulation and real-time visualization is provided in several aspects.

[0052] Several embodiments are configured to identify the borders or edges of abnormalities such as tumors, lesions, plaque, thrombus, etc. Such abnormalities may be vascular and within a vessel or located outside a vessel. During surgery, ablation or other intervention, it can be difficult to tell where an abnormality ends and healthy tissue begin. Thus, unnecessary multiple procedures may be required, which can lead to poorer outcomes such as increased cost and strain on the medical system, increased pain, and longer hospital stays. Many surgeries would be improved with better tissue visualization using the technology described herein. By determining the edge (e.g., border or boundaries) of tumors or other undesired target region, not only can healthy tissue be preserved but the likelihood is increased that complete removal or at least more of the undesired tissue / region is removed. Several embodiments allow medical professionals to clearly visualize tissue borders, blood vessels, nerves, lymph ducts, etc. in real time during surgery or other procedure, and additionally allow for post-procedure enhanced images. In some aspects, the imaging device can be placed in a vessel but is also able to visualize tissue (including abnormalities) outside the vessel. The enhanced images provided by various embodiments described herein (e.g., real time availability of enhanced images) allow precision surgical intervention that reduces the risk of error and additional corrective surgeries. Improved patient outcomes, including complete removal of cancerous tissue, lesions, plaque, etc. while preserving healthy tissue, is accomplished by the enhanced visualization described in several embodiments described herein. Further, visualization of vessels or tissues outside of vessels may be performed without dyes or radiation in many embodiments. Using AI, machine learning and / or data analysis, additional embodiments described herein can be further used to moreaccurately identify the distinction between healthy tissue and diseased tissue. Also, such tools may be able to predict whether a certain margin of tissue - which seems healthy at the time but is actually high risk to contain unhealthy cells for example - should be removed, which in turn reduces the likelihood that further surgeries are required. Tumors that can be visualized and optionally treated according to several embodiments herein include, for example, fibroids, polyps, abnormal cell clusters, etc. including but not limited to those located in reproductive organs such as the uterus, the nasal or ear cavity, rectum, colon, other intestinal regions or elsewhere. Cysts, cell growths, lumps, fluid-filled growths are examples of tissue abnormalities that can be visualized and optionally treated according to several embodiments. The ability to visualize the boundaries of such tumors, cysts and other growths allow for more precision excision, ablation or other treatment to (i) more completely remove the undesired tissue, (ii) remove only as much other tissue as is needed to prevent future re-occurrence (e.g., surgical margin), and / or (iii) preserve healthy tissue. In several embodiments, a system and method is provided herein to reduce the region of the surgical margin ablated, excised or otherwise treated by using the enhanced visualization technologies described herein.

[0053] As used herein, the terms edge, border and boundary are used interchangeably.

[0054] In several embodiments, two or more of the following features are provided in combination:

[0055] Artificial Intelligence: In several embodiments, the systems described herein, including for example the advanced intravascular ultrasound platform, leverage AI to enable image interpretation, enhance total- system capabilities, and streamline workflows to maximize the clinical value. In some embodiments, advantageously, physicians will not need to integrate (e.g., cognitively integrate) imaging data spatially and temporally to fully interpret the clinical condition. Instead, systems according to several embodiments described herein can leverage the power of AI with generational advancements to go beyond single image interpretation. In several embodiments, the AI-powered engine, for example, may include a workstation that enhances image interpretation with a simplified workflow improving overall useability. Machine learning is used in several embodiments. In one embodiment, the AI-ready processing power is designed to support real time and on-demand image interpretation (e.g., thereby increasing the speed and confidence in clinicians making decisions regarding diagnosis and / or treatment of tissue or a patient condition). The AI powered workstation can provide high end processing and an AI engine for advanced signal and image processing. In various embodiments, the native image data capture provides for superior image interpretation (e.g., border detection, identification and measurement of vessel size, vessel disease, dissection, plaque morphology, etc.). In several embodiments, the systems described herein provide simplified measurement via automated border detection (e.g., AI algorithms automatically identify borders of a lumen, vessel, tissue, lesion, plaque, implant, stent, balloon, etc.). In several embodiments, the system provides simplified measurement via semi-automated border detection (e.g., the user can manually adjust or modify automated AI algorithms that identify borders of a lumen, vessel, tissue, lesion, plaque, implant, stent, balloon, etc. with the border selection reconfigured based on user modifications). In one embodiment, AI plaque identification utilizes AI algorithms to automatically classify and identify types of plaque within the imaged area to provide user guidance on treatment options (e.g., using color coding, icons or text overlays can beused to indicate what type of condition, such as an irregularity such as plaque, may be present for the selected image). In several embodiments, the data driven platform is designed to collect data, simplify image interpretation, with AI processing power to support real time and on-demand image interpretation and increase ease of use and reduce user cognitive load to help (i) identify lumen size, (ii) visualize dissections, (iii) characterize disease morphology, (iv) locate and quantify stenosis, and / or (v) identify true lumen. In some embodiments, image interpretation is used to identify thrombus, thrombosis, clots, embolisms, plaque, calcium, tissue health, stent or balloon apposition, and / or stent or balloon “health” or condition. Image interpretation may involve imaging to evaluate quality and / or position of placement of an existing stent. Image interpretation can involve identifying position relative to lumen walls, determine level of and / or quality of tissue grown into and around the stent or balloon. In one embodiment, for example with a bioresorbable stent, image interpretation can involve (i) evaluating the amount of dissolving of the stent, (ii) determining if the dissolving of the stent is in accordance with expected decay patterns (e.g., determining whether the level of decay on one side of the stent similar to the other side of the stent, and if not, that may indicate a problem with stent placement, or if the stent is dissolving more rapidly than expected that could indicate the stent will not provide the tissue with the expected structural support). In several embodiments, AI is used in real time and may or may not be used in conjunction with recording data and using artificial intelligence in retrospect. In several embodiments, AI may be used whether in real time or alone, whether in real time and based on recordings, and / or whether based on recordings alone to identify various characteristics, including but not limited to, the size of the lumen, the presence of calcium, the grade of calcium, obstructions, lesions, deformities, placement of stents, occluders and other devices, etc. In some embodiments, AI is used to aid the physician in making a diagnosis.

[0056] AI may be used in real time in conjunction with imaging. This has several advantages in some embodiments, for example, real-time AI can be employed for data collection, predictive outcomes and / or correlations. In one embodiment, AI is used for predictive outcomes, e.g., determining co-morbidity in a given percent of cases where hard plaque is identified in a particular artery, such as in the femoral artery. In several embodiments, real time AI is accomplished by measuring and providing feedback identifying tissue borders and / or edges. In some embodiments, imaging as described herein is used to identify and / or guide the placement of an occluder in a peripheral vessel or in coronary (or other) tissue.

[0057] In one embodiment, the system can measure thickness and circumference and grades of calcium, which can dictate therapy. In several embodiments, blood flow (e.g., speckle visualization) is visualized with the system allowing identification of thrombus existence and thrombus parameters. In one embodiment, blood dynamics and / or speckle visualization may be displayed in adjacent frames. In several embodiments, visualization of a vein is possible when the catheter is in an artery and / or visualization of an artery is possible when the catheter is in a vein. In several embodiments, visualization in collateral tissue and vessels is achieved while the catheter is in a different vessel. For example, although the catheter is placed in a first vessel (the “interrogated vessel”), the enhanced imaging provided herein is capable of visualizing one or more non-interrogated vessels and structures. This isparticularly advantageous in some embodiments because the procedure can be performed more quickly (because multiple vessels do not have to be individually accessed) and because visualization of vessels and structures can be obtained in situations where catheter access may be difficult (small, tortuous, etc.) or undesired (e.g., unstable clots or vessel injury, etc.). In several embodiments, IVUS clarity of imaging visualization is comparable to an external ultrasound or computed tomography (CT).

[0058] Plug and Play Catheter: According to several embodiments, catheters optimized for vascular imaging are configured for superior pushability, tracking, and crossing for arterial and venous vasculature. In several embodiments, catheters have superior pushability to avoid kinking with sufficient column strength to advance the catheter through tortuous bends and occlusions in vasculature without buckling, over bending, or collapsing anywhere along the catheter (e.g., ability to cross an occlusion or constriction). In several embodiments, catheters have superior tracking for the ability of the catheter to follow a guidewire through tortuous bends in vasculature, having sufficient flexibility and strength to move along and advance along a guidewire to target locations within the vasculature. In several embodiments, catheters have superior crossing capabilities to cross occlusions, restrictions and constrictions within the vasculature, such as at sites with tissue blockage (e.g., stenoses, etc.) and / or implant blockages (such as stents, balloons, etc.). The systems described herein, such as an IVUS catheter, can include a rotational design that is plug and play and for example, can allow the catheter to be taken out of the sterile package and prepared for use without the need to flush the device. In one embodiment, the catheter has a single rotational ultrasound element. In several embodiments, the catheter includes an encapsulated coupling medium (e.g., coupling medium, medium, liquid, fluid, gel, etc.) that supports the spinning inner imaging core inside the catheter jackets. In one embodiment, the IVUS catheter is a plug and play catheter with a rotational IVUS design flush-less peripheral disposable imaging catheter with a full length of 280 cm with a working length of 150 cm compatible with a 0.014” guidewire and a 5F sheath, allowing the IVUS catheter proximal connector to attach to the Catheter Interface Module (CIM) outside of the sterile field. In one embodiment, the IVUS catheter is a plug and play catheter is a flush-less peripheral disposable imaging catheter with a full length of 250 cm with a working length of 110 cm compatible with a 0.035” guidewire and an 8F sheath, allowing the IVUS catheter proximal connector to attach to the CIM outside of the sterile field. Connecting outside of the sterile field optionally avoids having to drape an electromechanical unit or cabled motor unit inside of the sterile field in several embodiments. In several embodiments, the high definition (e.g., HD, UHD, HD+, etc.) imaging uses acoustic pulse echoes with a matched excitation frequency spectrum for optimal penetration, ultra high resolution, and high definition image quality. In several embodiments, the system is optimized for peripheral vascular imaging, coronary imaging, or both. The imaging core spins inside the polymer jacket using an inner drive shaft connected through a proximal hub / connector in one embodiment. The hub connector is optionally attached to the CIM after removal from its sterile catheter package. The transducer located at the distal tip of the imaging core can rotate up to 4000 rpm (e.g., 1, 10, 50, 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000 rpm and values and ranges therein) and receives echoes for processing into a circular image on a display, such as a monitor and / or a tablet display. Thelength of the catheter can be 8 to 10 feet long. In various embodiments the catheter can be taken out of the sterile package and prepared for use without the need to flush the device. The lengths can allow the catheter proximal connector to connect to the CIM outside of the sterile field. Connecting outside of the sterile field avoids having to drape a cabled motor unit inside of the sterile field in one embodiment. The catheter can include non-volatile memory that includes unique catheter identification, usage data, and calibration for optimal imaging performance. Calibration may include data related to measurements of electrical impedance versus frequency, acoustic sensitivity versus frequency, and / or beam profile data that is specific to the individual device according to some embodiments. In some embodiments, high definition imaging is enabled via acoustics and signal processing customized for peripheral vascular imaging, with superior resolution and optimal penetration. In several embodiments the acoustics and signal processing are customized for coronary vascular imaging with superior resolution and optimal penetration.

[0059] Catheter Interface Module: A CIM is a hardware interface between the system cable from the workstation and disposable catheters according to several embodiments. In several embodiments, the CIM provides the system (e.g., IVUS system) with a rotational drive and ultrasound signal processing functions. Custom electronics may control the motor that rotates the imaging core inside the catheter. The electronics may also transmit and receive ultrasound signals between the spinning transducer within the distal end of the catheter tip and the custom Ultrasound System Control (USC) board inside the workstation. In various embodiments, the CIM provides an interface to read and write non-volatile memory in, for example, the catheter. Memory can be used to calibrate an ultrasound transducer for each unique catheter. In one embodiment, catheter memory may be used to select the appropriate system configuration to achieve the best possible imaging performance. The CIM may transmit ultrasound signals, sensor data, and / or catheter information from a catheter to a workstation and / or at least one tablet, which may store the transmitted information in a non-volatile memory in one or more locations. In one embodiment, the CIM is mounted on a bed rail outside a sterile field. In several embodiments, the CIM is embedded or integrated into imaging control equipment, a workstation, a housing, a table, a bed, a pedestal, a platform, and / or a cart. In several embodiments, the CIM is located outside a sterile field. One or more ports to allow for seamless connection between IVUS systems and other imaging modalities are provided in several embodiments.

[0060] In several embodiments, the technologies described herein, including the IVUS flush-less technologies for example, are used with other medical imaging systems (such as cardiac catheterization lab systems), to provide an integrated healthcare portfolio for cardiologists. An integrated or otherwise coordinated platform, in several embodiments, can improve workflow between various imaging systems, including for example, x-ray systems. In one embodiment, stent placement and other procedures are optimized using the IVUS technology described herein together with x-ray, external ultrasound and / or other non-IVUS technology.

[0061] In several embodiments, the IVUS technologies described herein are used with other catheter- based imaging procedures and / or non-catheter-based imaging procedures. Imaging procedures may include ultrasound, x-ray, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography(PET), PET-CT, fluoroscopy, endoscopy, angiography, optical coherence tomography, intravital microscopy, 2D imaging, 3D imaging, etc. Several embodiments described herein utilize synchronized operation, imaging, and / or measurements from two, three or more imaging modalities (e.g., ultrasound, X-ray (including radiography, fluoroscopy, angiography, venography, etc.), magnetic resonance, PET scans, optical imaging (e.g., optical coherence tomography, light, laser imaging), etc.). Multi-modality synergies between IVUS and one or more additional imaging systems are achieved in several embodiments, including for example, enhanced visualization and image quality, decreased procedure time, increased precision in stent positioning and vessel measurements, improved workflow and reliability, and other benefits. Multi-modal systems including IVUS may be used, for example, to allow cardiologists to diagnose and / or treat vascular blockages and other defects that should, in turn, offer patients with improved cardiac outcomes, while reducing the overall cost burden to the healthcare system through efficient and effective integration with IVUS. A more robust image of vessel and organ structures (such as heart structure) can be obtained using various embodiments of the IVUS technologies described herein.

[0062] Co-Registration of Images: In several embodiments, an IVUS system provides co-registration data to provide a 1:1 co-location identification enabling therapeutic precision. Advantageously, several embodiments described herein can work collaboratively with, or independently from, co-registration with another imaging modality such as fluoroscopy, in which a software algorithm tracks radio-opaque (RO) catheter marker(s) or a RO transducer throughout a continuous fluoroscopy recording. Co-registration with angiography may be used, for example, to determine 3D shape of vessel, lumen and lesion, including lesion length, efficient stent selection, efficient location for stent landing zone, in an attempt to shorten procedure time, decrease contrast use, and make practitioners more comfortable with IVUS. Described herein, are several embodiments that accomplish one or more of these benefits with, or without, co-registration.

[0063] Tablet: A tablet comprising a hand-held wireless touchscreen computer used as the user interface for the IVUS system that can be docked onto a tablet mount is provided according to one embodiment. The tablet includes, for example, computational hardware unit for the tablet software. One, two, three or more tablets may be connected to the system (e.g., IVUS system). Having a wireless interface can simplify the setup by avoiding extra cabling in the catheter lab. Supporting multiple tablets allows for multiple points of interaction simultaneously and for flexibility in tablet positioning in several embodiments.

[0064] User Interface: In several embodiments, the tablet provides the user interface with an image centric approach for image controls buttons, simplified case browsing, timeline interaction, implicit recording vs explicit recording, labeling, compound measurements, procedure summary report are provided according to one embodiment. The modern user interface can be configured to address user needs for simple and intuitive interaction, with customized screen layouts creating persistent user-customizable screen layouts that allow users to adjust parameters such as color scheme and control positions (e.g., ability to optimize the display elements to support left or right-handed physicians). In some embodiments, color themes may be user selectable to support (i) color blindness, (ii)environmental preferences for optimizing readability, (iii) color theme with company / clinician office branded colors, (iv) mono-chromatic color themes, (v) high-contrast color themes, (vi) user modified color scheme. In several embodiments, intraluminal measurements use imaging to capture images to diagnose, measure, and plan for treatment of a variety of diseases and conditions. In several embodiments, systems described herein are used to capture images to diagnose, measure, and plan for treatment of a variety of cardiovascular diseases and conditions. In some embodiments the user interface includes a display one or more images or videos with one or more controls (e.g., buttons, slides, touch controls, etc.) for display, recording, taking snapshot / still image, video looping, linear measurement, area measurement, volume measurement, contrast control, brightness control, zooming capability, recording audio, sound, voice, memos, display of timelines, placement of bookmarks, display of data, notation writing device, virtual keyboard, trash / deletion, microphone, speaker, volume control, multiple display (of 1, 2, 3, 4, or more images or videos) with measurement capability. In several embodiments, compound measurements include one or more of the following: (i) computation of cross-frame and cross-recording metrics such as blockage to provide guidance to clinician and procedure reporting, (ii) computation of metrics within a single image or across multiple images acquired during a procedure, (iii) measurements such as include percent stenosis, ratios of maximum to minimum diameters, ratios of maximum to average diameters, ratios of minimum to average diameters, and (iv) customized compound measurement types based on selected procedure type or user preferences (e.g., customized by user, procedure type, labels, streamlines work flow, user defines for customized measurements and reporting). In several embodiments, variable recoding playback speed may be included with the system. In one embodiment, the user can adjust playback speed to improve visual interpretation and imaging window of a recording (e.g., “pullback”) to improve visual interpretation. In various embodiments, a reference to “pullback” movement of the catheter may refer to retracting the catheter in a proximal direction and also contemplate advancing the catheter within the vessel in a distal direction. Longitudinal movement comprises pullback or pulling back a catheter from a vessel or other lumen, pushing or otherwise advancing a catheter into a vessel or other lumen, or both.

[0065] A number of image interpretation algorithms may detect vascular features beyond the lumen of interest. In some embodiments, side branches and / or collateral vessels are identified. In another embodiment, collateral vessels are identified and tracked during the “pullback”. Collateral vessel tracking and visualization may assist in, and increase the confidence of, lumen identification when the collateral vessel is becomes in close proximity to the lumen of interest leading to insufficient imaging data to disambiguate each vessel when solely viewing a single image or even adjacent images. Existence of side branches and collateral vessels may also be graphically depicted on the timeline as an overlay or color coded graphic, and may also be shown as a 3D depiction along with the lumen of interest. The 3D depiction may be shown in a linearized fashion in an (X,Y,Z) coordinate frame where Z is the longitudinal axis, and the center of the catheter is locked to (X=0, Y=0) coordinate. The 3D depiction may be shown in a coordinate frame (X,Y,Z) where the center of the catheter is not locked to (X=0, Y=0) coordinate.

[0066] Imaging Screen: In several embodiments, the tablet, and / or the workstation, includes an imaging screen. For example, the workstation can project images to a separate display with the same or similar appearance as the tablet. In several embodiments, a system is configured to support a measurement screen displayed on tablet or workstation display. In several embodiments, the workstation includes an imaging screen, which for example can project images to a separate display. In various embodiments, a workstation display could be on the cart (part of the system), or as a separate monitor (e.g., a screen or monitor for display in a catheter lab). In some cases, a unique display may be generated to take advantage of screen size and screen capabilities and present similar information. For example, if the screen is not a touch screen, the screen may be configured to not display touchscreen buttons on the workstation display and enlarge the image presentation for improved viewing. In several embodiments, a simplified imaging screen is image centric having one or more of the following: (i) the image (e.g., an IVUS image) as most prominent with UI elements minimized to product a visually simple screen, (ii) touch screen buttons that trigger image actions are radially located around the image, and / or (iii) primary navigation buttons that are located in corner of the screen, such as the upper right, upper left, bottom right, and / or bottom left of the screen. Image orientation adjustment can optionally allow for user guided, or automated / auto-clocking of images based on anatomical signatures. In one embodiment, the user can rotate the frame orientation manually or use auto-clocking based on anatomical signatures or defined landmarks in the imaging, which can improve user experience by creating consistent image orientations for faster identification of anatomic location and identifying features in the image(s).

[0067] Measurement Screen: In several embodiments, the tablet, and / or the workstation, includes a measurement screen. For example, the workstation can project images and measurements to a separate display with the same or similar appearance as the tablet. In several embodiments, the workstation includes a measurement screen that, for example, can project images and measurements to a separate display. In several embodiments, a measurement screen provides various ways to measure features in the image(s) and allows the user to view area measurements details in multiple ways such as: length, depth, distance, area, minimum diameter, maximum diameter, average diameter, and other dimensional values. The display can also be customized based on the selected procedure or based on previously defined user preferences. In one embodiment, the measurement screen can include one or more of the following: (i) a left margin of the screen to the left of the image providing an area for measurement details, (ii) a right margin of the screen to the right of the image providing a timeline and interactive recording navigation, (iii) the ability to zoom out to the measurement summary screen, and / or (iv) the ability to quickly toggle between recording- centric views and complete procedure measurement summary screen to compare different images or measurements. In one embodiment, a measurement summary screen provides a zoom out to view a summary of all images and associated measurements (e.g., 4x4, m x n, etc.) and the ability to show a single image. In several embodiments, the system allows the user to toggle to a summary view of all bookmarked images and images with measurements (e.g., 4x4, m x n, etc.) within a procedure. The user can view multiple images at the same time or zoom into a single view for additional details. This feature allows for seamless viewing or editing of measurements. The measurement screen mayhave the ability to zoom in on a selected image and change to the measurement screen. In one embodiment, blood dynamics using speckle information of neighboring frames to calculate blood movement are provided.

[0068] Synergies for Vascular Intervention: In several embodiments, the IVUS system is configured for optimized vascular procedures. Several systems and methods described herein can be used for peripheral, coronary and other intravascular applications. Other embodiments are used in non-vascular intraluminal applications, such as endoscopy.

[0069] For example, endoscopes may be used with several features described herein. Transvaginal and other gynecological ultrasound devices may also include several features described herein. For embodiments in which EUS (endoscopic ultrasound) and other intraluminal imaging or imaging of other body cavities or organs is performed (and such imaging is not in vessel), the features described herein for “IVUS” or “catheters” should be understood to apply to intraluminal (or other cavity / organ) catheters, probes, tubes, scopes and other such devices.

[0070] In some embodiments, the systems and methods are configured and optimized for peripheral vascular procedures (and not for coronary vascular procedures). In one embodiment, systems and methods configured, designed or adapted solely or primarily for the peripheral vasculature comprise one or more of the following features: flexibility, steerability, length, diameter, material, and / or bending strength for improved pushability, tracking, and crossing (e.g., the ability to cross through obstructions or narrowing) in the lumen. Some of these features may also be incorporated for applications other than peripheral IVUS. In some embodiments, the system is configured to image and / or measure tissue before a therapeutic procedure, such as to identify and plan the therapeutic procedure. In some embodiments, the system is configured to image and / or measure tissue after a therapeutic procedure, such as to confirm the results and outcome of the therapeutic procedure. In some embodiments, the system is configured to image and / or measure tissue during a therapeutic procedure.

[0071] In various embodiments, both imaging and therapy are provided in a single device or in separate devices for use together (e.g., imaging device used before, during and / or after a therapeutic intervention). For example, one or more imaging technologies as described herein can be combined on the same catheter as one or more therapy elements, such as an integrated ultrasound imaging element located at or near the tip of (or otherwise along) a thrombectomy device. The thrombectomy device can also be a separate device that is delivered before, during or after the imaging device. Thrombectomy devices can be mechanical clot retrieval devices, clot aspiration devices, or a combination of clot retrieval and aspiration. Neurovascular, coronary and pulmonary clots are treated in several embodiments using the ultrasound imaging devices and methods disclosed herein together with (either integrated or separate) clot treatment devices. The clot treatment device can also include for example non-mechanical devices such as lytic or other drug delivery devices and energy delivery devices to disrupt / remove the clot or otherwise restore blood flow. Combinations of two, three or more therapies combined with the IVUS imaging technologies described herein are also provided (for example, ultrasonic or laser clot disruption with a lytic agent). The integrated IVUS and therapycatheter or probe can also be used, according to several embodiments, for restoring blood flow that is not caused by a clot.

[0072] Custom Ultrasound Control Electronics: Custom electronics are used in both the CIM hardware and a plug-in board on the workstation motherboard (e.g., USC board) according to one embodiment. In some embodiments, high speed processing, high dynamic range signal capacity, and high-end signal processing support precise control of transmit waveforms and receive processing to maximum spatial resolution, temporal resolution, and image contrast for superior image interpretation.

[0073] Secure Catheter Identification and Calibration: The catheter includes non-volatile memory that includes unique catheter identification and authentication, usage data, and calibration for optimal imaging performance according to one embodiment.

[0074] Real time and on-demand Vessel Border Detection: The processing power of the systems described herein enables real time and on-demand vessel border detection according to one embodiment. In one embodiment, when the display is paused / stopped the borders can indicate a confidence level either by color or by handle to adjust the border. In one embodiment, when the display is paused / stopped the borders can indicate a global confidence level for the automated border of an image, and / or a local confidence level in select regions of the border. Confidence level can be color coded or otherwise visually depicted on the image. Regions with low local confidence may have a graphical element, or handle, to adjust the border. In one embodiment, the IVUS system provides enhanced catheter navigation in the recorded frames using visualization of real time measured metrics without an external imaging system. In alternate embodiments, external imaging, such as fluoroscopy, is provided. External imaging may be leveraged to provide co-registration of a location of the IVUS catheter during a procedure. In several embodiments, co-registration may be partially or fully automated. In several embodiments, imaging may be conducted without automated co-registration, which may allow for more flexibility to use different components (e.g. components that may be more readily available to physicians and / or components for which physicians already have a level of comfort). Increased speed of procedures, reduced cost of medical care, and better patient outcomes may be accomplished in many embodiments.

[0075] Hands-free Commands / Voice Control: The ability to have a hands-free interaction with the systems described herein (e.g., IVUS system) allows the clinician to interact with the system without breaking the sterile field according to one embodiment. In several embodiments, voice commands provide hands-free tasks and assist in measurement and real time border detection. A unique aspect of voice control utilizes a select set of common system commands with a modernized workflow specific grammar context and social cue inference to allow for a wake-wordless command interaction to support a stream-lined imaging and measurement workflow in several embodiments. In various embodiments, hands-free voice control interaction allows the user to control the system without breaking the sterile field. In several embodiments, the voice command set has a direct correlation to the modernized user interface displayed on the tablet. In several embodiments, the system has a modernized workflow that enhances user experienceand overall usability. In some embodiments, the system (e.g., interactive user device such as a tablet or other components) may include a camera that captures hand gestures, which are interpreted and converted into system commands. In one embodiment, the system is configured to capture a face of the user via a camera and authenticate the user based on one or more facial features. In one embodiment, a voice control social cue may be either a wake- word, or inferred based on a pre-set minimum duration of silence before followed by a valid command. In one embodiment, volume level filtering with commands uttered below a specific acoustic level will be ignored to increase robustness. In one embodiment, the system includes audio filtering to lower the amplitude, or volume, of sounds not emanating from the direction of the user. The system can attempt to recognize the voice command phrase uttered after the minimum duration of silence. If the phrase is not recognized, the command will be ignored, and the system will resume waiting for the next social cue according to one embodiment. In several embodiments, the voice processor (tablet or tablet mount, or workstation) is configured for determining social cue. For example, in various embodiments a wake mode may be entered by social cue; a wake mode or command mode does not require a wake word to precede voice commands; and / or a wake mode may terminate based on a predefined duration or change in workflow state. Social cue may be a change in a workflow state, with a wake word, and / or a period of silence preceding a voiced command. Social cues may allow for improved voice interaction by reducing false positive voice responses.

[0076] Native Image Data Collection and Cloud-based Storage: In some embodiments, the systems described herein are designed to support native ultrasound sensor data collection. In several embodiments, sampled signal data includes amplitude and / or phase. This data, for example, is complete without loss including both phase and amplitude stored in a proprietary format and archived in a cloud-based data lake. This high-fidelity ultrasound data is used in one embodiment to drive future improved image generation and image interpretation, and optionally leveraging artificial intelligence and / or machine learning.

[0077] Remote Management, Service and Data Analytics: In several embodiments, the platform includes stream-lined device management that provides the ability for preemptive maintenance actions based on system metrics to maximize system availability and uptime. Insights into usability metrics can provide input for product refinements. Remote system management with procedure usage monitoring and dynamic preventative maintenance notification are provided in some embodiments. In some embodiments remote management can also include notifying IVUS System that updated software and / or firmware is available and allow for manual or automatic methods and systems to download the new software to the systems and install them.

[0078] Innovation Life Cycle Management: The system is a platform that will quickly improve based on input from both Data Analytics and Native Image Data Collection according to one embodiment. Product evolution managed through a lifecycle model includes for example: Native Data -> AI / ML feature dev -> Validation -> Remote Service Deployment.

[0079] Multi-Channel Processing Pipeline: The processing power of several embodiments described herein enable a unique data processing architecture featuring multi-channel processing according to one embodiment.Multi-channel processing allows for real time processing and image processing for the display of human interpretable images, while also processing for automated and / or semi-automated, computer based, image interpretation according to some embodiments. Using multi-channel processing, one or more processors may route data from a plurality of data sources, through a plurality of data processing pipelines, and route the IVUS image data to a plurality of data sinks. In one embodiment, the IVUS system is configured for multi-stream processes. In several embodiments, the IVUS system uses a multi-channel processing infrastructure that enables a unique data processing architecture featuring multi- channel processing. Multi-channel processing allows for real-time processing and image processing for the display of human interpretable images, while also processing for automated, computer based, image interpretation according to some embodiments. In one embodiment, the multi-channel processing infrastructure utilizes a complex data processing infrastructure that can combine data streams from multiple data sources, process them in a configurable set of data processing pipelines, and route them to a configurable set of data sinks. Flexible configuration for the data sources, data processing pipelines, and data sinks allows for assembling the infrastructure at runtime and reuse of components and sub-components according to some embodiments. In one embodiment, image series measurements with multi- frame, multi-channel processing is configured for one or multiple images. In one embodiment, multi-channel processing pipeline is configured synchronous to ultrasound acquisition timing, via decimated by N periods to allow processed aggregated data blocks.

[0080] Workstation: A workstation is a high-performance computer that includes a central processing unit (CPU), volatile memory, graphics processing unit (GPU), disk non-volatile storage, wireless antennas, and custom ultrasound transmit and receive electronics according to one embodiment. The workstation can be the computation hardware unit for the easy to use workstation software. The workstation can be a high-performance computation unit that includes GPU processing to support edge-based AI / ML computations in real time, or on-demand. Standard discrete workstation GPU(s) and an interface executed by the workstation can provide the platform to leverage rapid pace of progress in commercial GPUs. The workstation can provide connectivity and data analytics, remote diagnostic, service, and / or upgrade capabilities. In several embodiments, the IVUS system includes electronic storage (e.g., secure catheter ID, customized acoustic data, usage data, etc.). In one embodiment, the workstation includes high-speed DRAM to capture an entire pullback study of raw ultrasound data for live viewing and on-demand post-processing after the pullback is complete.

[0081] Automatic Configuration of Networked Components and Accessories: In several embodiments, the IVUS system may be used within a single hospital or clinic network to automatically discover workstations and exchange information on how to connect to them. The user (e.g., clinician, assistant, technician, trained service technician, IT administrator, etc.) can be presented with a list of discovered IVUS workstations and can associate a component / accessory with a single click. Communication parameters, e.g., IP addresses and ports, can be configured automatically. In one embodiment, zero configuration networking can create a computer network when computers or peripherals are interconnected using automated assignment, distribution, and location data for networked devices. Insome embodiments, cybersecurity aspects such as the discovery and information exchange can be protected with a security features, e.g., security keys.

[0082] Maximized local network WIFI Bandwidth and Synchronization Protocol for Multiple Clients: in various embodiments, a combination of internal Wi-Fi card, its driver settings, (e.g., Linux driver), and configurations in Access Point mode (e.g., wireless protocol, encryption, band, channel, etc.) can create, for example, a wireless network (e.g., akin to a hotspot) with enough bandwidth (e.g., with at least a 250 KB late-cine frame size and 60 fps, and 2 client devices, that comes out to 240 Megabits per second) to support two or more tablets. In one embodiment, the network has a synchronization protocol that keeps (i) the latest state of the workstation synced to the two or more tablets, (ii) the latest state of a master-tablet can be synced to a secondary-tablet in the face of disconnectivity (e.g., failure of power, network, etc.). A combination of underlying network-architecture overlaid with this application-level network-protocol will achieve low latency and simultaneous ease-of-use for hospital personnel in several embodiments. Combinations of the features above, in several embodiments, advantageously provide ease of setup, reduced cognitive load, streamlined user interactions and efficient clinical workflow. In several embodiments, the IVUS system provides image centric approach for image controls buttons, simplified case browsing, timeline interaction, implicit recording vs. explicit recording, labeling, compound measurements, and / or procedure summary reporting.

[0083] In several embodiments, imaging as described herein is used to diagnose whether a patient is suitable for a particular intervention or further diagnostics. In various embodiments, 2D and / or 3D intraluminal visualization is enabled. In one embodiment, 2D imaging includes an image in a single plane. In several embodiments, 3D imaging includes a volumetric representation of tissue or a lumen. In some embodiments, 3D imaging is reconstructed via algorithms interpolating a series of 2D images across a third dimension, taking a series of individual 2D images and estimating linear progression along the third dimension, and may employ AI to produce a 3D volumetric representation of the interpolated 2D images. In some embodiments, 3D model generation may involve obtaining 2D cross-sectional images of a vascular object such that a position along the vein or artery (e.g., an insertion length) can be recorded by an encoder or other sensor. Drawing each 2D cross section in 3D at the insertion length at which the cross section was recorded can allow a 3D model of the vascular object to be built. In one embodiment, adding an electro-magnetic sensor to the catheter tip can allow the position of the catheter tip to be recorded as the 2D images are obtained, thus allowing a 3D model of the vascular structure to be created. In one embodiment, one or more algorithms convert series of IVUS 2D images and signal data into volumetric 3D visualization. In one embodiment, 3D visualization is produced via interpolation of linear and / or nonlinear vascular structure geometry and acoustic reflections from a tissue. In one embodiment, pixel based interpolation is used to visualize vascular anatomy in three dimensions. In several embodiments, a series of cross sectional two dimensional IVUS images and / or signals are generated via pixel based cut view images of a vessel showing acoustic reflection information along a length of a lumen. In one embodiment, 3D visualization is produced via algorithms for creating anatomical contour borders via smooth 3D surface rendering. In several embodiments, AI is employed to create 3D visualization data and images.

[0084] In several embodiments coronary systems and methods are provided. In several embodiments, devices (such as coronary IVUS catheters) employ larger diameters, higher rigidity, and modified coronary specific pushability, tracking, and / or crossing characteristics. Catheters for coronary applications may apply different ultrasound frequencies to account for variance in tissue lumen size: for example, the peripheral vasculature may have larger vessel diameters, so lower frequencies can be used for ultrasound imaging to image at farther distances from the center / IVUS catheter. In some embodiments, coronary vessels have smaller diameters, so may use imaging ultrasound frequencies around 60 MHz, while peripheral imaging may use lower frequencies, such as around 40 MHz or less. In some embodiments, coronary application may also measure pressure within the lumen via a Fraction Flow Reserve (FFR) wire. In some embodiments, coronary IVUS catheters may employ a larger diameter guide catheter to surround part or all of the coronary IVUS catheter, with IVUS imaging employed when partially extended from the guide catheter. In some embodiments, coronary IVUS catheters need less column strength for pushability or crossing because of the presence of a guide catheter.

[0085] In several embodiments, image enhancement may include, for example, resolution and / or contrast image enhancement to improve image quality. The image enhancement may include a nonlinear image enhancement (NLIE) function that can preserve edges and facilitate edge detection enhancements that make it easier for an AI / ML algorithm to find features of interest. For example, NLIE may be configured for improving edge and detail image quality and / or reducing noise and / or blurs from images by, for example, removing portions of an image if the portion does not meet a threshold probability of accuracy value.

[0086] In several embodiments, an IVUS system comprises a workstation with a computer with a CPU, memory, a GPU, storage, wireless antennas, software, and electronic circuitry to transmit and receive data. In one embodiment, the GPU is a high-performance computation unit that includes or consists essentially of GPU processing to support edge-based AI / ML computations in real time, or on-demand. In one embodiment, a discrete workstation GPU and interface provides platform to leverage rapid pace of progress with GPUs.

[0087] In one embodiment, the workstation includes or consists essentially of a motherboard component, and a USC board. The ultrasound system control board provides, in several embodiments, high speed processing, high dynamic range signal capacity, and high-end signal processing support precise control of transmit waveforms and receive processing to maximize spatial resolution, temporal resolution, and image contrast for superior image interpretation. The ultrasound system control board may interface to one or more drivers. The one or more drivers may create and register characteristics of devices (e.g., PCB and registration of each catheter and its individual characteristics).. In some embodiments, the one or more drivers may allocate memory in a kernel.

[0088] Imaging and diagnosis of intravascular or extravascular tissue is accomplished herein in several embodiments, including identification of irregularities. The term “irregularities” as used herein may be given its ordinary meaning and shall also include vascular or other malformations, constrictions, occlusions, dilations, disease, and injury. Irregularities may also include lesions, thrombus, aneurysm, dissection, plaque (e.g., hard plaque, soft plaque,vulnerable plaque, calcified plaque, substantially non-calcified plaque, fibro-fatty plaque), fistulas, tumors, neoplasia, gallstones, kidney stones, polyps, cysts, etc., and measuring morphology assessment wherein such irregularities are within vessels, other bodily lumens or other target sites. In several embodiments, irregularities may also include stent or balloon malapposition, dissection (e.g., post atherectomy, post balloon angioplasty, etc.), determining etiology of compression, under-expansion of a stent or other device, and issues with IVUS-guided sizing and grading of severity of an irregularity or under expansion of a stent, such as an iliac vein stent. Irregularities in the esophagus, stomach, and small intestine may be viewed using several embodiments described herein (e.g., through endoscopic ultrasound imaging). Tumors include, for example, fibroids, polyps, abnormal cell clusters, etc. and may be benign or cancerous, including but not limited to those located in reproductive organs such as the uterus, the nasal or ear cavity, rectum, colon, other intestinal regions or elsewhere.

[0089] In addition to the identification of irregularities, several embodiments herein are used to facilitate relevant measurements and preparation for deploying stents and / or balloons, and are useful for planning of treatment by medical practitioners.

[0090] After identification of irregularities, appropriate treatments may be used on the patient. For example, image-guided treatment of tumors, thrombus, plaque, etc. may be used in which imaging and therapeutic capabilities exist on a single device or multiple devices. Several embodiments include, for example, percutaneous coronary intervention for coronary artery lesions, intravascular imaging-guided percutaneous intervention for peripheral vascular lesions, and / or intravascular imaging-guided percutaneous interventions in arteries and / or veins. In several embodiments, the IVUS system is configured for optimized peripheral vascular procedures. In several embodiments, the IVUS system is configured for optimized peripheral vascular procedures and is not configured for coronary vascular procedures. In several embodiments, the IVUS system is configured for coronary procedures. In several embodiments, the IVUS system is configured for neurovascular procedures (including but not limited to cerebral vessels). In several embodiments, the IVUS system is configured for intravascular ultrasound-guided thrombectomy, including but not limited to mechanical thrombectomy. In some embodiments, the IVUS system is configured for ultrasound-guided pulmonary embolectomy. In several embodiments, simultaneous, real-time IVUS guidance is provided for procedures such as thrombectomy / embolectomy, stent placement, clot aspiration, other coronary or neurovascular procedures, etc. In several embodiments, the system may be configured for operation in vessels of 1 – 10 mm (e.g., 2 – 8 mm, 3 – 5mm, 6 – 9mm and overlapping ranges thereof), including but not limited to neurovasculature. In one embodiment, access to neurovasculature can include various catheter lengths to facilitate multiple access sites for the brain, including up to 200cm (e.g., 25-75cm, 75-180cm, etc.).

[0091] Although several embodiments described herein described IVUS, the technology described herein are also used for intraluminal imaging (other than intravascular). For example, several embodiments are used for imaging, diagnosing, and / or providing an image-guided intervention in the digestive tract (including but not limited to colonoscopy, endoscopy, etc.), esophagus, stomach, intestine, rectum, sinus (including ENT (ear, nose, throat) forexample), eye, for ocular purposes, ear, nose (e.g., for nose bleeds such as epistaxis), throat, for urology purposes, ureter (and other urological tissue), bladder, uterus, fallopian tubes, lungs, brain, etc. The systems and methods described herein may be used in conjunction with an endoscope rather than an IVUS catheter and support identification and diagnoses of gastrointestinal tumors, such as tumors in the intestines and / or biliary ducts. Similarly, the systems and methods described herein may be used to image a sinus cavity (or other ENT application) using IVUS. Tumors that can be visualized and optionally treated according to several embodiments herein include, for example, fibroids, polyps, abnormal cell clusters, etc. including but not limited to those located in reproductive organs such as the uterus, the nasal or ear cavity, rectum, colon, other intestinal regions or elsewhere. ENT (ear, nose, throat) visualization are provided in several embodiments, as are ocular application to help image various eye structures. In some embodiments, the ultrasound imaging technologies described herein are used to visualize fluids, whether internal or externally delivered. Drug delivery, including for example via fluid or nano particle delivery, may also be visualized. Such visualization may be helpful for confirming delivery to the desired target region, saturation, etc. in a vessel or other lumen, to a tumor or other abnormality (such as thrombus, plaque, calcium, etc.). Visualization may be before, after and / or during delivery of a drug and real-time visualization is provided in several aspects. In one embodiment, ultrasound is also used to facilitate drug delivery.

[0092] As used in the summary above, as well the description below, where a device or a method “comprises” or “includes” (the two being interchangeable) certain features or steps, such device or method may also “consist essentially of” some of those features or steps if identified as such (i.e. recites “consists essentially of” in the claims).

[0093] The technology described herein, including technical components and electronic architecture for generating high image quality with rotational IVUS with extended catheter lengths are used in several embodiments with flush-less, encapsulated, sealed IVUS catheters to reduce air bubbles and eliminate the need to flush acoustic coupling medium including the technology described in Patent Serial No. PCT / US2024 / 024045 filed April 11, 2024 entitled Flush-Less Intravascular Ultrasound Technology; intraluminal image focusing with spinning single element ultrasound transducer via modification of image (e.g., angular diffraction, phase, amplitude, time shift, compositing backscatter reflected images) including the technology described in Patent Serial No. PCT / US2024 / 024035 filed April 11, 2024 entitled Spinning Single Element Ultrasound Transducer and Focusing Technology; and manually assisted pullback for spatial alignment measurements, voice control, position sensors (e.g., encoder) including the technology described in U.S. Patent Serial No.63 / 531,266 entitled Systems and Methods of Manually Assisted Pullback for Spatial Alignment Lengthwise Measurements in Intravascular Ultrasound Imaging and Patent Serial No. PCT / US2024 / 041134 filed August 6, 2024 entitled Systems And Methods Of Manually Assisted Movement For Spatial Alignment Lengthwise Measurements In Intravascular Ultrasound Imaging, and the plug & play catheters, interface modules, workstation, universal mounts to a bedrail or mobile cart outside sterile field, user interface tablet, microphone and speakers, software, measurements, AI / ML, hands-free voice control, native image data collection, cloud-based storage, securecatheter identification & calibration, vessel border detection, remote service, data analytics, multi-channel processing, efficient clinical workflow, ease of setup and use; optimization for peripheral vascular procedures; synergies with intervention / image guided therapy including the technology described in U.S. Patent Serial No.63 / 546,058 entitled Systems And Methods For Intravascular Ultrasound, and Patent Serial No. PCT / US2024 / 051451 filed October 15, 2024 and entitled Systems And Methods For Enhanced Ultrasound Imaging, wherein all of the disclosures of such patent filings are herein incorporated by reference. U.S. Provisional Application No.63 / 632,966 filed April 11, 2024 entitled “Electronic Architecture For Intravascular Ultrasound Technology” is incorporated by reference herein.

[0094] In several embodiments, a method for classifying tissue type or abnormality for one or more locations of interest in a vessel or other lumen / region of a patient includes: receiving ultrasound image data of the region (e.g., from a vessel intravascularly or other lumen) of the patient; extracting patient-specific vessel / lumen geometry of the patient from the ultrasound image data; extracting geometric features from the patient-specific geometry of the patient; and / or classifying different types of tissues or abnormality for one or more locations of interest in the vessel / lumen based on the extracted geometric features using a trained machine-learning based model trained based on ultrasound images obtained from ultrasound catheters operating at different frequencies and based on ultrasound images of multiple different types of vessels (or other lumens / tissue).

[0095] In several embodiments, a computer-implemented method of assessing a vessel of a patient includes: receiving intravascular ultrasound image data of the vessel of the patient; extracting information from the intravascular ultrasound image data of the vessel of the patient; storing the information in memory; and / or classifying different types of tissue for one or more locations of interest in the vessel based on the extracted and stored information using a trained machine-learning based model that is trained based on intravascular ultrasound images obtained from intravascular ultrasound catheters operating at different frequencies and based on intravascular ultrasound images of multiple different types of vessels.

[0096] The methods may optionally include: (i) types of tissue or abnormalities that are selected from the group consisting of: intima, media, adventitia, lumen, plaque, and calcium, (ii) generating an output for display on a graphical user interface that indicates the different types of tissue, (iii) different types of tissue are displayed in different colors, (iv) generating a confidence measure associated with the classifying, (v) outputting the confidence measure on a display of a graphical user interface, (vi) confidence measure is a global confidence measure or a local confidence measure, and / or (vii) the geometric features include a cross-sectional measurement, a thickness, and / or a length.

[0097] In several embodiments, a computer-implemented method of assessing a vessel of a patient includes: receiving one or more intravascular ultrasound images of the vessel of the patient; extracting data from the one or more intravascular ultrasound images; storing the data in memory; performing a vessel feature detection task on the extracted and stored data using a machine learning based model trained to detect at least a first vessel feature in intravascular ultrasound image data, wherein performing the vessel feature detection task comprises generating anautomated output associated with the first vessel feature; and / or utilizing the automated output associated with the first vessel feature, performing a tissue classification task using a machine learning model trained to classify tissue in the one or more intravascular ultrasound images, wherein performing the tissue classification task comprises generating an automated result of the tissue classification task. A Machine learning model may be trained broadly using IVUS images from one more manufacturers or sources and from one or more imaging frequencies to provide a robust training set with variation in image resolution and depth of penetration. The Machine learning model may also be trained with lumens from both venous and arterial IVUS images (e.g., from the device and / or one or more sources) to provide a robust detection of the lumen when plaque or thrombus is present. Broadly training a model can also be applied to train a Machine learning model to detect irregularities.

[0098] The method may include: (i) extracted data that includes amplitude and phase data, (ii) the first vessel feature is a lumen boundary and the vessel feature detection task is detection of the lumen boundary, (iii) automated output associated with the first vessel feature that is graphical output of the lumen boundary, (iv) the tissue classification task includes classifying plaque, calcium, a dissection and / or a thrombus, (v) the tissue classification task includes identification of a guidewire or medical device in the one or more intravascular ultrasound images, (vi) classifying the plaque or calcium that includes generating a qualitative or quantitative assessment of the plaque or calcium, (vii) outputting the automated result on a display, (viii) the automated result indicates different types of tissue based on the tissue classification, and / or (ix) the indication is provided using different colors.

[0099] In several embodiments, a computer-implemented method of training a neural network for tissue type characterization within intravascular ultrasound images using a disparate-source training approach includes: receiving multiple sets of digital intravascular ultrasound images of different types of vessels and obtained using multiple different intravascular ultrasound catheters operating at different imaging frequencies; applying one or more transformations to each digital intravascular ultrasound image including geometry-based data augmentation and intensity-based data augmentation to create a modified set of digital intravascular ultrasound images; creating a first training set comprising the received multiple sets of digital intravascular ultrasound images and the modified set of digital intravascular ultrasound images, and a first set of unmodified digital intravascular ultrasound images; training the neural network in a first stage using the first training set; creating a second training set for a second stage of training comprising the first training set and a second set of unmodified digital intravascular ultrasound images; and / or training the neural network in the second stage using the second training set. Optionally, the different types of vessels may include coronary vessels, peripheral vessels, arteries, and / or veins. The multiple different intravascular ultrasound catheters may be manufactured by different manufacturers.

[0100] In several embodiments, the imaging system is configured for use in a blood vessel, in a bodily lumen other than a blood vessel, and / or in tissue located outside a lumen.

[0101] In several embodiments, the devices, systems and methods may use artificial intelligence (AI) to determine patient eligibility for further intervention and additionally use of the system and AI to reduce risk that patient receives unnecessary further interventions. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The following drawings are for illustrative purposes only and show non-limiting embodiments. Features from different figures may be combined in several embodiments.

[0103] Fig.1 illustrates an IVUS system according to one embodiment.

[0104] Fig.2 illustrates an imaging core cable according to one embodiment.

[0105] Fig.3 illustrates an ultrasound system control (USC) board according to one embodiment.

[0106] Fig.4 illustrates a catheter interface module (CIM) according to one embodiment.

[0107] Fig.5 illustrates a transmit signal amplifier according to one embodiment.

[0108] Fig.6 illustrates an impedance matching network according to one embodiment.

[0109] Fig. 7 illustrates an analog front end (AFE) receiver of a transceiver according to one embodiment.

[0110] Fig.8A illustrates a motor control algorithm according to one embodiment.

[0111] Fig.8B illustrates a motor control algorithm according to one embodiment.

[0112] Fig. 9 illustrates a transmit / receive sequence controller configuration according to one

[0113] Fig.10A illustrates a transmit / receive sequence for IVUS imaging according to one embodiment.

[0114] Fig.10B illustrates a transmit / receive sequence for IVUS imaging according to one embodiment.

[0115] Fig.10C illustrates a transmit / receive sequence for IVUS imaging according to one embodiment.

[0116] Fig.10D illustrates a transmit / receive sequence for IVUS imaging according to one embodiment.

[0117] Fig.10E illustrates a transmit / receive sequence for IVUS imaging according to one embodiment.

[0118] Fig.11A illustrates a transmit signal and a receive signal according to one embodiment.

[0119] Fig.11B illustrates a transmit signal and a receive signal according to one embodiment.

[0120] Fig.11C illustrates a transmit signal and a receive signal according to one embodiment.

[0121] Figs.12A-12D illustrate coded and uncoded waveform according to various embodiments.

[0122] Fig.13 illustrates a cross-section of a system cable according to one embodiment. DETAILED DESCRIPTION

[0123] According to several embodiments, the systems and methods described herein are directed towards improved ultrasound systems, such as IVUS systems. The IVUS systems provide a more user-friendly experience for clinicians directing the IVUS treatment and higher quality IVUS images. For example, using several embodiments described herein, the IVUS system can be set up and used more efficiently, taking less time andpersonnel resources. In several embodiments, the IVUS system is configured for optimized peripheral vascular procedures (including, e.g., procedures with carotid, subclavian, pulmonary, aortic (abdominal and / or thoracic), renal, iliac (arterial or venous), femoral popliteal (femoropopliteal, fem-pop) bypass, infrapopliteal, arteriovenous (AV) fistula, femoral, popliteal, and tibial vasculature, vessels, arteries, veins, and capillaries). In several embodiments, the IVUS system is configured for optimized peripheral vascular procedures and is not configured for coronary vascular procedures. In several embodiments, the IVUS system is configured for optimized coronary vascular procedures.

[0124] With respect to pulmonary procedures for example, in some embodiments, the systems described herein are used for diagnostic, therapeutic pulmonary applications, such as endobronchial ultrasound, bronchoscopy, thoracoscopy, pleuroscopy, COPD diagnosis and treatment, video-assisted thoracic surgery (VATS), echocardiograms, pulmonary function tests, and diagnosis and minimally invasive treatment of lung and respiratory disorders. Nasal, sinus, throat, and tracheal imaging (and optional intervention) may be performed according to several embodiments.

[0125] In several embodiments, the IVUS system is configured for neurovascular procedures (including but not limited to cerebral vessels). In several embodiments, the IVUS system is configured for intravascular ultrasound- guided thrombectomy, including but not limited to mechanical thrombectomy. In some embodiments, the IVUS system is configured for ultrasound-guided pulmonary embolectomy. In several embodiments, simultaneous, real-time IVUS guidance is provided for procedures such as thrombectomy / embolectomy, stent placement, clot aspiration, other coronary or neurovascular procedures, etc. Neurovascular, coronary and pulmonary clots are treated in several embodiments using the ultrasound imaging devices and methods disclosed herein together with (either integrated or separate) clot treatment devices. With respect to diagnostic and therapeutic applications in a vessel, for example in the neurovascular space, in some embodiments, the systems described herein are used for diagnostic, therapeutic brain applications. For example, several embodiments may be used to image cerebral vessels to image and thereby facilitate diagnosis and / or treatment of thrombus, and / or other tissue damage and / or disease states. The small vessels surrounding the eye, whether neurovascular or ocular, may be well-suited for the enhanced visualization technologies described herein. In several embodiments, the system may be configured for operation in vessels of 1 – 10 mm (e.g., 2 – 8 mm, 3 – 5mm, 6 – 9mm and overlapping ranges thereof). Several embodiments provide catheter lengths to accommodate multiple access sites to smaller vessels, including up to 200cm (e.g., 25-75cm, 75-180cm, etc.).

[0126] In some embodiments, the ultrasound imaging technologies described herein are used to visualize neuromodulation, such as nerve ablation, blocks, and stimulation. Such visualization may be helpful for confirming delivery of the neuromodulation (e.g., by heat, cryotherapy, chemical, radiofrequency, microwave, acoustic, etc.) to the desired target nerve(s) in a vessel, other lumen or region. This is turn may be used to increase the likelihood that the target nerve is treated, while preserving healthy nerves and other healthy tissue surrounding the target nerve. Visualization may be before, after and / or during neuromodulation and real-time visualization is provided in several aspects.

[0127] Although several embodiments described herein described IVUS, the technology described herein are also used for intraluminal imaging (other than intravascular). For example, several embodiments are used for imaging, diagnosing, and / or providing an image-guided intervention in the digestive tract (including but not limited to colonoscopy, endoscopy, etc.), esophagus, stomach, intestine, rectum, sinus (including ENT for example), ureter (and other urological tissue), bladder, uterus, fallopian tubes, lungs, brain, etc. The systems and methods described herein may be used in conjunction with an endoscope rather than an IVUS catheter and support identification and diagnoses of gastrointestinal tumors, such as tumors in the intestines and / or biliary ducts. Similarly, the systems and methods described herein may be used to image a sinus cavity (or other ENT application, such as treatment for nose bleeds such as epistaxis) using imaging ultrasound, such as IVUS. ENT (ear, nose, throat) visualization are provided in several embodiments, as are ocular application to help image various eye structures. In various embodiments, IVUS uses ultrasound for imaging only (without therapy). In various embodiments, IVUS uses ultrasound for therapy only (without imaging). In various embodiments, IVUS uses ultrasound for both imaging and therapy. According to several embodiments, one or more imaging technologies as described herein can be combined on the same catheter as one or more therapy elements, such as an integrated ultrasound imaging element located at or near the tip of (or otherwise along) a thrombectomy device. The thrombectomy device can also be a separate device that is delivered before, during or after the imaging device. Thrombectomy devices can be mechanical clot retrieval devices, clot aspiration devices, or a combination of clot retrieval and aspiration. Neurovascular, coronary and pulmonary clots are treated in several embodiments using the ultrasound imaging devices and methods disclosed herein together with (either integrated or separate) clot treatment devices. The clot treatment device can also include for example non-mechanical devices such as lytic or other drug delivery devices and energy delivery devices to disrupt / remove the clot or otherwise restore blood flow. Combinations of two, three or more therapies combined with the IVUS imaging technologies described herein are also provided (for example, ultrasonic or laser clot disruption with a lytic agent). The integrated IVUS and therapy catheter or probe can also be used, according to several embodiments, for restoring blood flow that is not caused by a clot.

[0128] In several embodiments, the technologies described herein, including the IVUS technologies for example, are used with other medical imaging systems (such as cardiac catheterization lab systems), to provide an integrated healthcare portfolio for cardiologists. An integrated or otherwise coordinated platform, in several embodiments, can improve workflow between various imaging systems, including for example, x-ray systems. In one embodiment, stent placement and other procedures are optimized using the IVUS technology described herein together with x-ray, external ultrasound and / or other non-IVUS technology. According to several embodiments, cardiac imaging as described herein is used in intracardiac imaging (e.g., may be used instead of intracardiac echocardiography (ICE) procedures). The architectures, AI / ML technologies, edge detection, voice control, plug and play, and other aspects may be advantageous and configured for intracardiac imaging (and in one embodiment may be used to supplement or improve ICE techniques). In some embodiments, features and / or dimensions of the cathetercomponents described herein are adjusted for intracardiac delivery (e.g., in some cases larger than the dimensions for blood vessels). In some embodiments, cardiac imaging is used for one more of the following: guiding procedures such as ablation to treat arrythmias, septal defect closure, monitoring for pericardial effusion, evaluation of the inner surface of the heart and valves, transeptal catheterization, confirming balloon position, guide valve placement, and general cardiac monitoring during intervention.

[0129] In several embodiments, the IVUS technologies described herein are used with other catheter- based imaging procedures and / or non-catheter-based imaging procedures. Imaging procedures may include ultrasound, x-ray, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), PET-CT, fluoroscopy, endoscopy, angiography, optical coherence tomography, intravital microscopy, 2D imaging, 3D imaging, etc. Several embodiments described herein utilize synchronized operation, imaging, and / or measurements from two, three or more imaging modalities (e.g., ultrasound, X-ray (including radiography, fluoroscopy, angiography, venography, etc.), magnetic resonance, PET scans, optical imaging (e.g., optical coherence tomography, light, laser imaging), etc.). Multi-modality synergies between IVUS and one or more additional imaging systems are achieved in several embodiments, including for example, enhanced visualization and image quality, decreased procedure time, increased precision in stent positioning and vessel measurements, improved workflow and reliability, and other benefits. Multi-modal systems including IVUS may be used, for example, to allow cardiologists to diagnose and / or treat vascular blockages and other defects that should, in turn, offer patients with improved cardiac outcomes, while reducing the overall cost burden to the healthcare system through efficient and effective integration with IVUS. A more robust image of vessel and organ structures (such as heart structure) can be obtained using various embodiments of the IVUS technologies described herein. In some embodiments, the ultrasound imaging techniques described herein can be used instead of other visualization and diagnostic devices. For example, several embodiments do not use radiation or dyes.

[0130] In several embodiments, IVUS systems with catheters incorporating rotating and / or translating imaging transducer(s) may include catheters which are connected to an electromechanical unit (EMU) which drives the movement of the transducer(s) as well as the transmission and reception of ultrasound signals to generate images. Certain prior IVUS systems have been designed with unfavorable limitations requiring the EMU to be within the sterile field so catheters can reach the appropriate location in the human body. Some of these EMUs must be draped with a sterile bag when placed in the sterile field during procedures. This can lead to a more cumbersome and time-consuming set up process. Moreover, the electromechanical unit can have design constraints affecting image quality for safe thermal operating temperatures inside the sterile draping, such as a plastic bag. Limitations on thermal operating temperature can limit the type and operating bounds of components which can be included in the EMU, which can affect the fidelity of ultrasonic signals transmitted and received by certain systems. This can impact image quality. Handling or adjusting the position of certain short catheters in the body is also more challenging when connected to the EMU as the EMU has weight and girth. There is a need to develop improved IVUS systems with IVUS cathetersthat are connected to the EMU where the EMU is outside of the sterile field. There is also a need for solutions that address the loss of ultrasound signal quality due to the increased length of catheters in order to effectively reach the EMU outside the sterile field. There is further a need for solutions that provide increased total lengths of catheters with high image quality that can be connect to an EMU inside or outside the sterile field.

[0131] In several embodiments, IVUS systems 100, such as shown in Fig.1, may include catheters which are connected to an EMU which drives the catheter’s imaging core to generate images. The IVUS systems and methods described herein include embodiments of an IVUS catheter having a sufficient length such that the proximal end of the catheter can be mechanically and electrically coupled to a catheter interface module (CIM), an electromechanical unit, outside of a sterile field. The IVUS system can provide superior images with high spatial resolution at a high frame rate such that the IVUS images can be viewed in real-time. In some embodiments, the IVUS systems include specialized electronic components and subcomponents, such as a catheter interface module (CIM) 115, a workstation 118, and an ultrasound control board (not shown) inside a workstation. Advantageously, the IVUS system 100 can be set up such that the non-disposable components of the system, e.g. the CIM 115, the ultrasound system control board, and / or the workstation 118, can all be placed outside of the sterile field, removing requirements for additional components or draping of such components in the sterile field, for example, an EMU.

[0132] Fig.1 illustrates an IVUS system 100 according to one embodiment. The IVUS system 100 may be used to image and diagnose intravascular blood and tissue. In various embodiments, the IVUS system 100 is configured for ease of setup and use. Identification of irregularities or diseased vessels may be accomplished using the IVUS system 100. In addition to the identification of vascular irregularities, several embodiments herein are used to facilitate relevant measurements and preparation for deploying stents and / or balloons, perform thrombectomies, perform atherectomies, and are useful for planning of treatment by medical practitioners, e.g., physicians, surgeons, and / or medical technicians in various fields, such as vascular surgery, interventional cardiology, and / or radiology throughout the body from the heart and its associated coronary vasculature to the peripheral vasculature.

[0133] The IVUS system 100 includes an IVUS catheter 102. The IVUS catheter 102 may include a flexible elongate member with a lumen 108. In some embodiments, the flexible elongate member may be between 6 - 12 feet (e.g., 6, 7, 8, 9, 10, 11, and 12 feet, and values and ranges therein) in length. For example, the IVUS catheter 102 may be at least 3 feet (ft), at least 4 ft, at least 5 ft, at least 6 ft, at least 7 ft, at least 8 ft, at least 9 ft, at least 10 ft, at least 11 ft, at least 12 ft, or at least 13 ft in length. Telescoping members may or may not be included. The flexible elongate member may include a working length portion 130 which may be inserted into the patient. In some embodiments, the working length portion 130 of the IVUS catheter 102 may be a fixed length. In some embodiments, the working length portion 130 of the IVUS catheter 102 has a length configured for connection to a catheter interface module outside of a sterile field. The working length portion 130 of the IVUS catheter 102 may be, for example, at least 90 cm, at least 100 cm, at least 105 cm, at least 110 cm, at least 120 cm, at least 135 cm, at least 137 cm, at least 141 cm, at least 149 cm, at least 150 cm, at least 160 cm, at least 175 cm, at least 176 cm, at least 177 cm, at least 180cm, at least 210 cm in length (e.g., 90, 100, 110, 125, 150, 175, 200, or 210 cm in length including values therein). The IVUS catheter 102 may include a catheter jacket. The catheter jacket may include one or more polymer materials. The elongate flexible member may include a sheath. For example, the sheath may be a 5F sheath or an 8F sheath. The flexible elongate member may include one or more lumens. In various embodiments, the IVUS catheter 102 may include a hydrophilic coating. In various embodiments, the IVUS catheter 102 may include one or more radiopaque markers.

[0134] The IVUS catheter 102 may include the distal working length portion 130 and a proximal extension portion 135. The distal working length portion 130 may be mechanically coupled to the proximal extension portion 106.

[0135] The proximal extension portion 106 may have respective length of 120 centimeters or greater, 87 centimeters or greater, 77 centimeters or greater, 73 centimeters or greater, 73 centimeters or greater, 68 centimeters or greater, 43 centimeters or greater, 41 centimeters or greater, 37 centimeters or greater, 29 centimeters or greater, 18 centimeters or greater, or 1 centimeter or greater. In some embodiments, the working length portion 130 and the proximal extension portion 106 may be connected by a midshaft hub 140. The midshaft hub 140 may couple the catheter jacket of the distal working length portion 130 and the catheter jacket of the proximal extension portion 106.

[0136] In various embodiments, the IVUS catheter 102 includes an imaging core 104 in a lumen 108. The imaging core 104 may include a transducer 105, an imaging core electrical wire (not shown), and an imaging core cable 110. The transducer 105 may be disposed at a distal end of the imaging core 104 in the lumen 108. The transducer 105 may comprise monolithic lead zirconate titanate (PZT), composite PZT, a capacitive micromachine ultrasonic transducer (CMUT), a piezoelectric micromachined ultrasonic transducer (PMUT), a unitary crystal, a single crystal, a single acoustic element, or multiple acoustic elements, or similar acoustic transducer with one or multiple acoustic elements. The imaging electrical core wire may be a coaxial cable, a twisted pair cable, or combinations of these types of cables. The imaging electrical core wire may transmit signals to and from the transducer 105. For example, the imaging electrical core wire may transmit a transmit signal from a processor to the transducer 105 and may transmit a receive signal from the transducer 105 back to the processor.

[0137] The imaging electrical core wire may be disposed inside the imaging core cable 110 according to some embodiments. The imaging core cable 110 may be a metal cable tube or torque coil. In some embodiments, the imaging core cable 110 may include one or more outer layers with one or more outer diameters. For example, the imaging core cable 110 may include two outer layers. In another example the imaging core cable 110 may include three outer layers. The outer layers may each include a plurality of filars (e.g., threads). The plurality of filars may be made from metal, such as stainless steel. Each outer layer may have a number of filars, a filar size, a filar twist direction, and / or an angle of filar twist. In some embodiments, the filar twist of each layer may alternate orientations. In one embodiment, a single outer diameter cable tube is used. Advantageously, multiple outer layer configurations of theimaging core cable 110, such as a dual outer layer configuration, may provide improved torque control and decrease non-uniform rotational distortion (NURD) in longer IVUS catheters.

[0138] Fig.2 illustrates an imaging core cable 202 according to one embodiment. The imaging core cable 202 may include a distal portion 204 and a proximal portion 206. The distal portion 204 of the imaging core cable may be mechanically coupled to the proximal portion 206 of the imaging core cable via a coupler 208. The coupler 208 may be a metal component (e.g., a metal coupler). In some embodiments, the coupler 208 may be welded to the distal portion 204 and the proximal portion 206. In one embodiment, the distal portion 204 and the proximal portion 206 have different layers with different outer diameters (e.g., dual layer, dual OD cable tube). In some embodiments, the outer diameter of the proximal portion 206 may be greater than the outer diameter of the distal portion 204.

[0139] Returning to Fig.1, the IVUS system 100 may include a catheter interface module (CIM) 115 and a workstation 118 according to various embodiments. The CIM 115 may include ultrasound transmit and receive circuitry and components as well as an actuator configured to rotate the imaging core 104. The CIM 115 may be placed in mechanical and electrical communication with the IVUS catheter 102 via a proximal connector hub 116 of the catheter 102. The workstation 118 may include a memory and at least one processor. In various embodiments described herein, the workstation 118 may include an ultrasound control (USC) board (not shown). The at least one processor of the workstation 118 may be configured to instruct the components of the IVUS system 100 such as the USC and / or CIM 115 to generate transmit signals, capture receive signals (e.g., a backscatter signal), and / or rotate the imaging core 104. The at least one processor may process the receive signals to generate IVUS image(s) in real- time. The at least one processor may provide the IVUS image(s) to be displayed on a display 120.

[0140] In several embodiments, the technology described herein incorporates technology described in U.S. Patent Serial No.63 / 459,312 entitled Systems and Methods for Flush-Less Intravascular Ultrasound Catheter, including but not limited to paragraphs 7-8, 62, 69, 71, 76-77, 80-81, and 112 bodily incorporated herein: Several embodiments provide a rigid proximal connector hub with a seal (e.g., a flexible seal, wherein flexible in some embodiments is elastic, malleable, bendable, modifiable, adjustable, accommodating, adaptable, pliable, supple, pliant, and / or resilient) as part of a catheter to support an encapsulated medium while allowing an inner imaging core to rotate without leaks of the medium and to prevent air ingress into the catheter lumen. A flexible seal surrounds a driveshaft (e.g., drive cable, drive coil, drivetrain, drive actuator) of the rotating imaging core inside a rigid proximal connector hub holding the medium inside the lumen connected to the hub while the core rotates. The circular seal may be compressed onto the driveshaft with sufficient force to prevent leaks while still allowing a motor (e.g., connected to an imaging console) to rotate the inner imaging core at rates to support high imaging frame rates. Example materials include elastic polymers like nitrile, ethylene propylene rubber, and fluorocarbons and similar materials. Two seal housings may be arranged to fix the flexible seal between the connector hub and the rotating driveshaft. The surfaces of the two seal housings are precisely mated to ensure proper pressure is applied to the flexible seal allowing the driveshaft to rotate without too much friction and also preventing the medium from leaking proximally through the flexible seal. An adhesivemay optionally be applied to the outer circumference of the flexible seal to prevent leaks around the flexible seal. The flexible seal may be assembled inside the rigid proximal connector hub to ensure a precise fit. In some embodiments, this is advantageous over placing a seal inside a flexible catheter or similar catheter body / lumen as the flexibility may contribute to medium leaks or air ingress during use. During normal operation in typical clinical environments the pressure differential on the two sides of a flexible seal is generally insignificant so there is little force to push the medium out or to pull air in. However, outside the clinical theatre, such as during product transport, the catheter may be subject to extreme temperature swings. When exposed to extreme drops in temperature, the coupling medium may change from a liquid to a solid state either increasing or decreasing the encapsulated medium volume and then returning back to a default volume after the extreme temperature exposure. This volume change typically requires some flexibility of the seal so air is not pulled into the inner lumen. Air that gets into the lumen may migrate to the distal transducer of the spinning imaging core and degrade image quality. The dual seal housings are preferred in one embodiment for precise assembly and sealing, however a single housing on the proximal side only may also be used. A fill port is included in the rigid proximal connector and is sealed after filling the catheter lumen with the medium, according to several embodiments. The fill port may be different shapes to facilitate the connection to the filling equipment. After filling the catheter lumen the fill port is closed off with a plug and / or adhesive to prevent any air ingress. A preferred fill port, in one embodiment, has the inlet most proximal, juxtaposed to the flexible seal to aid in purging all air bubbles during the fill process. Methods to seal the exit port after filling the lumen are also provided herein. A distal plug is attached to a removable wire in one embodiment. Removable wires include for example NiTi (nitinol), stainless steel, or other flexible wires. According to several embodiments, (i) the wire is fed through the lumen exiting the exit port leaving the distal plug loosely floating in the distal section of the lumen; (ii) the filling process is completed once all bubbles are removed from the lumen as air is purged from the exit port; and (iii) upon inspection of no air bubbles, the distal plug is bonded to the wall of the lumen either with a heating process that reflows the materials together and / or a small amount of adhesive is inserted into the exit port bonding the plug to the luminal walls. The wire may be removed easily from the plug after the distal plug is bonded to the catheter lumen. A colorant may be added to the medium before the filling process starts aiding inspection for leaks and identification of gas bubbles. The colorant adds optical contrast aiding in the identification of the medium and gas bubbles improving the manufacturing process. In one embodiment, the lumen is configured to receive rotational transducer and a driveshaft. The driveshaft mechanically couples the rotational transducer to an actuator. The lumen may be configured to receive a coupling medium. In various embodiments, the coupling medium is biocompatible, sterilizable, and / or acoustically compatible. For example, the coupling medium may be polyethylene glycol (PEG), PEG with some fraction of water, water, saline, glycerin, and / or oil (e.g., natural, mineral, etc.), or a combination thereof. In various embodiments, the coupling medium does not include PEG, water, saline, glycerin, or oil. In various embodiments, the coupling medium is degassed prior to insertion into the lumen. In one embodiment, the coupling medium has a viscosity greater than water that reduces or eliminates non-uniform rotational distortion (NURD). In one embodiment, an elongate member that includes a lumen and a rapid exchange (RX) lumenaccording to one embodiment. In some embodiments, the elongate member comprises one or more housing layers. In some embodiments, the RX lumen at a distal tip that includes a distal plug. The lumen of the elongate member may receive a rotating transducer that is mechanically connected to a driveshaft. The lumen may also receive a coupling medium. The coupling medium may be a liquid or a gel. For example, the coupling medium may be polyethylene glycol (PEG), PEG with some fraction of water, water, saline, glycerin, natural oils, or a combination thereof. In various embodiments, the coupling medium has a density and speed of sound value that are similar to the catheter jacket material to prevent or reduce unwanted reflections from the medium / jacket interface and prevent or reduce refraction of the acoustic beam. PEG may be provided in a range of 5-90% (e.g., 5-10%, 10-25%, 20-50%, 40-80%, and overlapping ranges therein). PEG may be provided in various low molecular weight grades of polyethylene glycol. PEG may be provided in various medium molecular weight grades of polyethylene glycol. PEG may be provided in various high molecular weight grades of polyethylene glycol. In one embodiment, an isometric view of a connector hub of one embodiment of an IVUS catheter system. In one embodiment, the connector hub is a rigid material with one or more flexible seals to support an encapsulated medium while allowing an imaging core and driveshaft to actuate via rotation and / or linear motion along the catheter axis without leaks of the medium and prevent air ingress into the catheter lumen with one or more seals and / or valves. In one embodiment, the flexible seal surrounds the driveshaft (extending though flexible seal and distally through the connector hub and into the lumen of the catheter) inside a rigid connector hub holding the medium inside the lumen while the imaging core rotates. In one embodiment, the flexible seal is a circular seal that is compressed onto the imaging core of the connector hub with sufficient force to prevent leaks while still allowing a motor or actuator in an imaging console to rotate the imaging core at rates to support high imaging frame rates. In various embodiments, the flexible seal is made of nitrile, nitrile rubber, nitrile butadiene rubber, Buna-N, acrylonitrile butadiene rubber, ethylene propylene rubber, ethylene propylene diene monomer rubber, fluorocarbons, fluoroelastomer, fluorine rubber, synthetic rubber polymer (such as Viton and others), silicone rubber, rubber derived from acrylonitrile, and similar materials. The connector hub is connected to a proximal connector of an IVUS catheter. In some embodiments, the connector hub is connected to the driveshaft of an imaging core. In one embodiment, the connector hub is integrated with the catheter body such that the connector hub forms the proximal end of the catheter body. In one embodiment, the connector hub is separate and distinct from the catheter body such that the connector hub is adjacent to, or near, a proximal end of the catheter body. In one embodiment, the connector hub comprises a medium fill port. The medium fill port is configured to connect to a source or reservoir of an acoustic coupling medium. The medium fill port may be configured for inserting the acoustic coupling medium through the connector hub and into the lumen of the elongate member of the IVUS catheter. The medium fill port is sealed after filling the catheter lumen with the medium. The medium fill port may be shaped to accommodate different connector geometries. The medium fill port may be disposed proximal to the distal interface and is distal to a flexible seal and the proximal interface. The position of the medium fill port may aid in purging all air bubbles during the fill process. In some embodiments, the medium fill port may be sealed with an adhesive and / or with a plug similar. In one embodiment, the fill port has the inletmost proximal, juxtaposed to the flexible seal to aid in purging all air bubbles during the fill process. In various embodiments, the connector hub includes one or more flexible seals. The flexible seal may surround the driveshaft inside a connector hub and seal a coupling medium inside a lumen of a catheter body while the core rotates. The flexible seal may be compressed onto the core with sufficient force to prevent leaks while still allowing an actuator of the console via the proximal interface to rotate the imaging core at rates to support high imaging frame rates. In some embodiments, the flexible seal may be assembled inside the connector hub to ensure a precise fit. The connector hub may include one, two, three or more flexible seals. In one embodiment, a distal end of an elongate member with an exit port configured for sealing after filling the catheter lumen with an acoustic coupling medium according to one embodiment. The elongate member includes a lumen, which includes a distal port. The lumen may be filled with a coupling medium, and the distal port may be sealed to reduce or eliminate air bubbles from the lumen, and to reduce or eliminate the need to flush the catheter lumen. In some embodiments, a distal plug may be attached to a removable wire. In one embodiment, the distal plug is a polymer material. In various embodiments, the distal plug may be made of Pebax (polyether block amide), nylon or other polymer materials such that bonding and / or thermally fusing the plug with the catheter body is effective. In some embodiments, the distal plug may be shaped to conform with the geometry of the distal port. The removable wire may be NiTi (nitinol), stainless steel, or another flexible material. The wire may be fed through the lumen from a proximal port at the proximal end towards the distal port. The wire is configured, in one embodiment, to exit the distal port, leaving the distal plug in the distal section of the lumen. As the filling process is completed, and once all bubbles are removed from the lumen, the distal plug may be bonded or adhered to the wall of the lumen. The distal plug may be drawn to the distal port by the wire such that the distal plug seals the distal port. In some embodiments, heat may be applied to the distal end of the elongate member, causing the distal plug to melt with and / or adhere to the wall of the lumen. In some embodiments, an adhesive may be inserted into the distal port, bonding the plug to the walls of the lumen. The wire may be removed from the plug after the distal plug is bonded to the lumen. In one embodiment, an acoustic coupling medium according to an embodiment in various embodiments of a catheter. In various embodiments, the acoustic coupling medium has similar acoustic properties to blood, is biocompatible, and is configured for filling the imaging lumen without (or by minimizing) bubbles within imaging plane and acoustic window. In various embodiments, the acoustic coupling fluid may include up to 4 mL within the catheter (e.g., up to 3.5, 3.3, 3.1, 3.0, 2.8, 2.6, 2.4, 2.1, 1.9, 1.7, 1.5 mL and additional volumes therein). In one embodiment, the acoustic coupling medium is colored for ease of monitoring fill process and inspection for bubbles. Acoustically attractive media have density and speed of sound values that are similar to the catheter jacket material in several embodiments. Increased differences in density or speed of sound values between a medium and the catheter jacket may result in unwanted strong acoustic reflections and refracted sound pulses that degrade image quality. In several embodiments, media in several embodiments include one of polyethylene glycol (PEG), PEG with some fraction of water, water, saline, glycerin, and natural oils. The percentage of the non-PEG fraction may be 80 to 20% (e.g., 80%, 70%, 60%, 50%, 40%, 30%, 20% and overlapping values and ranges therein), and in certain embodiments a range of50 to 30% (e.g., 50%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 35%, 35%, 30% and overlapping values and ranges therein) as the propensity for dissolved gases is lower for the latter, respectively.

[0141] In several embodiments, the technology described herein incorporates technology described in U.S. Patent Serial No.63 / 497,962 entitled Spinning Single Element Ultrasound Transducer and Focusing Methods, including but not limited to paragraphs 38-39 and 44 bodily incorporated herein: In various embodiments, the angular or circumferential spatial resolution of IVUS imaging may be limited by the passive directivity function of the transducer given by the physics of diffraction. In various embodiments, the IVUS system has an imaging axial resolution of 10 – m (e.g., 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375, 400, 425, 450, 475, 500 m and any values and ranges therein). In various embodiments, the IVUS system has an imaging lateral resolution of 10 – 500 m (e.g., 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 125, 145, 150, 175, 185, 200, 215, 225, 250, 275, 290, 300, 325, 350, 375, 400, 425, 450, 475, 500 m and any values and ranges therein). In various embodiments, the IVUS system has an imaging lateral resolution of 2- 20 degrees (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 degrees and any values and ranges therein). In various embodiments, rotating or spinning a single ultrasound transducer about a single axis while imaging improves the clarity and sharpness of the imaging by 5-200% or more. In various embodiments, IVUS imaging resolution is improved 5 – 200% (e.g., 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200% and any values and ranges therein). In one embodiment, passive directivity involves no active means to control temporal delays or phases to actively focus or steer the ultrasound beam with a single transducer element, such as may be done with multi-element transducer arrays. The response of the imaging system to an isolated point target is called the point-spread function which can be collapsed to show only the lateral response when concerned specifically with that dimension. Certain factors that are under control of a device designer to optimize the lateral response characteristics of such a passively focused device include the imaging frequency (such as, for example, in the range of 1 – 90 MHz (e.g., 1-10, 10-15, 10-20, 10-25, 10-30, 10-40, 15-30, 15-35, 15-40, 15-50, 15-60, 15-70, 20-30, 30-40, 40-50, 20 -25, 20-30, 20-40, 20-45, 20-50, 25-35, 25-40, 25-45, 25-50, 30-45, 30-50, 40-45, 45-50, 50-60, 50-70, 50- 80, 55-75, 55-65, 60-70, 60-90, 70-80, 70-90 MHz and any values and ranges therein) In one embodiment, the device a frequency of 60 MHz. In several embodiments, lateral response characteristics of such a passively focused device are optimized, such as the acoustic aperture size (which is equal to the transducer element size for the case of a single element device), and potentially altering the fixed focusing characteristics by means of a physical lens, such as moving the focal length from “infinity” (which can be produced by a flat transducer) to a shallower depth. In various embodiments, fixed focus depths are in a range of 1 – 10 mm (e.g., 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.7, 1.8, 2.0, 2.4, 2.5, 2.7, 2.8, 2.9, 3.0,3.1, 3.2, 3.3, 3.4, 3.5, 3.7, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, and 10.0 mm and any values or ranges therein. In one embodiment, the fixed focus depth is 2.5 mm – 3.5 mm (e.g., 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5 mm and any values or ranges therein). In one embodiment, focus control of single element IVUS devices is constrained without a lens. An aperture with no lens has effectively an ideal focus performance at thedepth of the near-field to far-field transition (called the “natural focus”) and beyond. In one embodiment, a single element IVUS relies on this natural focusing achieved with no lens. However, different materials are typically in the acoustic path, such as a polymer jacket which can act as a lens whether desired or not. Focus performance may be improved or degraded by the choice of geometry and material specifications of the device. In one embodiment, a high performance mechanical lens may be used, but is typically cost prohibitive. Standard rotational IVUS acoustic apertures are unfocussed, in the sense that there is no specific surface layer lens on the element to focus its directivity pattern. Standard devices are typically housed in polymer catheter sheath whose material properties will have an imperfect focusing effect by refraction through the standard catheter body. By judicious choice of material, the catheter body can shift the effective focal depth shallower, but it will come at the expense of an ideal deep focus. It is not possible to focus individual lines at more than one depth with a standard single element, and the near field typically suffers.

[0142] In several embodiments, the technology described herein incorporates technology described in U.S. Patent Serial No.63 / 531,266 entitled Systems and Methods of Manually Assisted Pullback for Spatial Alignment Lengthwise Measurements in Intravascular Ultrasound Imaging, including but not limited to paragraphs 5-7, 46, 49, 55, 60-66, 72-73, 76, 80, 83-84, 86-89, and 91 bodily incorporated herein: Several embodiments described herein provide systems and methods for determining a lengthwise, longitudinal position of a manually advanced ultrasound imaging catheter and measuring the length of a longitudinal, lengthwise movement of the ultrasound imaging catheter within a blood vessel, lumen, or other region. Manually assisted longitudinal, lengthwise pullback of an IVUS catheter may be implemented for spatial alignment measurements of tissue using IVUS imaging. In several embodiments, distance- based length measurements along an intraluminal axis of a patient are provided, such as measurements of vascular lengths using distance-based measurement along the vascular axis. Several embodiments provide relative position along an axial catheter dimension during sequentially acquired IVUS images within a human vessel using manual translation of a catheter with efficient clinical workflow. The position information allows for measurement among images acquired during translation with respect to the axial dimension of a catheter without use of a bulky device in the sterile field to actuate movement of the catheter. Advantageously, several embodiments described herein do not require fully automated co-registration with another imaging modality such as fluoroscopy, in which a software algorithm tracks radio-opaque (RO) catheter marker(s) or a RO transducer throughout a continuous fluoroscopy recording. In several embodiments, systems and methods for IVUS based measurements do not require integration with another modality and reduces fluoroscopy exposure to the patient. Consistent operator-to-system or system-to-operator interaction may be more reliable than a software-based recognition system for RO markers where weak signals or poor-quality signals may limit accuracy. Co-registration with angiography is used, for example, in an attempt to shorten procedure time, decrease contrast use, and make practitioners more comfortable with IVUS. Described herein, are several embodiments that accomplish one or more of these benefits without co-registration. In some embodiments, use of the manual pullback helps correlate fiducial landmarks and waypoints within a patient’s body, including in complex cases, such as dimensional measurements of tissue damage, occlusions, lesions for treatment planning, such as atherectomyor stent placement (e.g., determining where in a vessel stenting will be begin and end). Although co-registration is still available with the systems and methods described herein, the ability to image without automated co-registration may allow for more flexibility to use different components (e.g. components that may be more readily available to physicians and / or components for which physicians already have a level of comfort). Increased speed of procedures, reduced cost of medical care, and better patient outcomes may be accomplished in many embodiments. According to several embodiments, the systems and methods described herein are directed towards improved intravascular ultrasound imaging and measurements. In several embodiments, the systems and methods provide vessel-wise distance measurements for a recording of IVUS images within a continuous human vessel using manual translation of a catheter. An IVUS recording that is made while withdrawing the catheter within a vessel is a workflow process that is referred to as a “pullback.” Augmenting a pullback with distance measurement information adds clinical value and workflow efficiently by facilitating length measurement between images in the pullback. In several embodiments, IVUS imaging is used to diagnose unhealthy vasculature and to guide and assess therapies. In various embodiments IVUS can be used for imaging only. In various embodiments IVUS can be used for therapy only. In various embodiments IVUS is used for imaging and therapy, with therapies such as heating, coagulation, ablation, ultrasound HIFU, delivery of drugs, anticoagulants (such as heparin, warfarin, dabigatran, apixaban, and / or rivaroxaban), biologics, lytics, thrombolytics, microbubbles, and / or interventional therapies. In one embodiment, the IVUS system includes a disposable catheter used to deploy an ultrasound image acquisition unit within the vasculature and an accompanying imaging system or console. In one embodiment, a processor detects a lengthwise movement of the catheter. The processor may determine a lengthwise position of the catheter using an output device to dictate a lengthwise movement speed to a user and / or using input device to receive the lengthwise movement speed from the user. In some embodiments, the processor may associate IVUS images with the lengthwise position of the catheter at the time the IVUS images were captured. For example, the processor may annotate the IVUS images to include the lengthwise position. The longitudinal position may be defined relative to an anatomical point of interest. The imaging core comprises a transducer may be a single-element transducer or a multi-element array of transducers in various embodiments. In one embodiment, a single ultrasound transducer (e.g., with only a single element, without multiple elements, without a plurality of elements, and / or without an array of elements) is positioned at an intravascular site with a catheter for acoustic imaging. In various embodiments, a multi-element array may be a 2, 8, 10, 12, 16, 24, 32, 50, 64, 100, 128 element array. In one embodiment, the transducer is rotated by an actuator while the one, two, or more receiving transducers may remain static. The catheter body has a flexible wall extending along the length of the catheter from a proximal end to a distal end. The catheter body also includes one or more lumens, such as a lumen. In one embodiment, the lumen may extend from the proximal end to the distal end of the catheter body. In one embodiment, the lumen may extend from a proximal end to a distal portion of the catheter body. The lumen may be defined by a wall of the catheter body. In one embodiment, the wall of the catheter body is flexible. According to some embodiments, the lumen may be defined by a wall of a member inserted into the catheter body. In some embodiments, the catheter body may includetwo or more lumens. The lumen may be sealable and comprise a proximal port and a distal port. In various embodiments, images may be formed by a rotating single element or by a multi-element array. During live imaging the acquisition is repeated at an imaging frequency (such as, for example, in the range of 1 – 90 MHz, e.g., 1-10, 10-15, 10-20, 10-25, 10-30, 10-40, 15-30, 15-35, 15-40, 15-50, 15-60, 15-70, 20-30, 30-40, 40-50, 20 -25, 20-30, 20-40, 20- 45, 20-50, 25-35, 25-40, 25-45, 25-50, 30-45, 30-50, 40-45, 45-50, 50-60, 50-70, 50-80, 55-75, 55-65, 60-70, 60-90, 70-80, 70-90 MHz and any values and ranges therein). In one embodiment, live imaging the acquisition is repeated at frame rates to provide a real-time 2D imaging modality (such as, for example, frame rates in the range of 12 – 120 Hz, e.g., 12, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90, 100, 110, 120 Hz). The pullback recording of sequentially acquired IVUS images made while withdrawing the catheter within a vessel can be used to survey a length of a tissue along the blood vessel. In one embodiment, stacking the 2D images recorded during a pullback a volume of data can be constructed. In one embodiment, by stacking a chosen diameter from each of the annular images, an alternate 2D image referred to as a “strip” image can be formed. In one embodiment, the stacking of data from images acquired during a pullback constitutes spatial sampling of the lengthwise dimension, which is out-of-plane with respect to the individual IVUS images. In one embodiment such a stacked image may not be formed, but knowledge of lengthwise separation of individual images is still attainable and advantageous. In some embodiments, one or more markers are spaced along a portion of the length of the catheter body. In various embodiments, 1 – 40 markers (e.g., 1, 2, 4, 5, 6, 7, 8, 9, 10, 12, 16, 20, 24, 25, 30, 32, 35, 38, 40 markers and any values and ranges therein) are distributed along the catheter body. In some embodiments, the markers are evenly spaced longitudinally along the catheter body. For example, the markers may be spaced 0.5 – 6.0 cm (e.g., 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.5, 1.8, 2.0, 2.3, 2.5, 2.7, 3.0, 3.3, 3.5, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.4, 4.5, 4.8, 5.0, 5.3, 5.5., 5.8, 6.0 cm apart and any values and ranges therein). In one embodiment, the markers is radiopaque (RO).

[0143] In various embodiments the markers are disposed on an external surface of the catheter body. The markers may be printed rings disposed on or embedded in the external surface of the catheter body. In one embodiment, the markers are radiopaque ring members disposed within or upon the catheter body. In some embodiments, the marker may be major marker or a minor marker. Major markers may indicate a longitudinal distance such as 2 - 10 cm (e.g., 2, 3, 5, 7, 8, 10 cm and any values and ranges therein), while minor markers may be disposed between major markers and positioned at a particular fraction of the distance between the two major markers. For example, the minor markers may be disposed at every 1 / 10th, 1 / 5th, 1 / 4th, 1 / 3rd, or ½ of the longitudinal distance between two major markers. In some embodiments, the major and minor marker have different sizes such that major markers may be distinguished from minor markers in an image, such as an X-ray image (e.g., radiography, fluoroscopy, and / or angiography image). In one embodiment, a manual pullback IVUS image series capture is recorded while manually translating the catheter along a vessel length. The lengthwise position of the images in the series are estimated by a user / system interaction. This interaction will leverage visible bands or markers on the IVUS catheter that indicate longitudinal translation past one or more surrounding anatomical references. For example, the progressof the translating catheter can be judged by the movement of radiopaque (RO) markers past bony fiducials visible in fluoroscopy or by visible catheter markings past the entry point to the body. In one embodiment, the interaction is a system-to-operator type, such as using audible pacing clicks to pace the operator’s pullback. In one embodiment, the interaction is an operator-to-system type, such as voice entered waypoint indicators given by the operator to the system. By correlating the capture time and physical catheter translation, an image series may be rendered against a length axis in the direction of pullback motion (such as in the case of a “strip” image). In one embodiment, an image series is rendered against lengthwise position, vessel-wise lengths, e.g., distances between images, such as may correspond to desired stent start and end positions in the series can be obtained and documented through the IVUS system user interface. Lengthwise distances between anatomical points of interest can be obtained and utilized with the IVUS images to aid clinical therapy decisions such as selected balloon lengths for percutaneous transluminal angioplasty and expandable stent lengths. In one embodiment, such lengthwise distances between images in the series are obtained whether the image series has been rendered against lengthwise positions or not. In some embodiments, the IVUS catheter system may include an output device. The output device may be an audio output device, a haptic output device, a display device, or a combination thereof. An audio output device may be one or more speakers, headphones, or ear pieces configured to emit a sound, tone, click, word, or phrase. A haptic output device is configured to apply a force to a user, generate a vibration, generate a movement, or a combination thereof. A display device may be any device suitable for providing a visual output, such as a television, a monitor, a mobile device, a tablet, a smart watch, projector screen, visor display, eyepiece, or the like. The output device may provide an output from the system to an operator / user, such as a notification, indication, instructions, and / or feedback to the operator / user. In some embodiments, the processor may generate an output and instruct the output device to provide the output to the user. As discussed in greater detail below, the processor may instruct the output device to provide a pacing instruction or pacing notification to a user. For example, at the instruction of the processor, the output device may provide an audio instruction or notification in response to a longitudinal movement of the catheter body. In some embodiments, the IVUS catheter system may include an input device for the operator / user to communicate with the system. The input device may include one or more of a microphone, a tactile input device. A tactile input device may be a keyboard, a button, a switch, a pedal etc. The input device may receive an input from a user, such as a voice- input. In some embodiments, the processor may be placed in electronic communication with the input device and configured to receive inputs from the input device. For example, as discussed below, the processor may receive a pacing input from a user via the input device. According to some embodiments, the catheter system may not include a motorized pullback device. Instead, the catheter body may be moved manually in a longitudinal direction by a user, such as a physician. The system-to-operator interaction output may include a plurality of pacing instructions from the process to the user that dictates a pace at which the user should move sequential markers of the one or more markers should align with the starting anatomical point. For example, a series of sounds, such as beeps, may be played by the system as a pacing output for the user to listen to. The beeps may be played with a steady tempo to dictate to the userthe processor’s recommended pullback speed. At a first beep, a first marker of the one or more markers should be aligned with the starting point. In some embodiments, an X-ray image (e.g., radioscopy, fluoroscopy, angiography) is taken of a portion of the patient, and the position of one or more radiopaque markers relative to the starting point may be assessed. The catheter may be moved by the user in a proximal or distal direction, and via the pacing output provided by the system at a second beep, a second marker of the one or more markers is aligned with the starting point. This sequence may continue such that sequential markers of the one or more markers are aligned with the starting point upon each subsequent beep, e.g. a third marker may be aligned at a third beep, a fourth marker may be aligned at a fourth beep, and so on. In some embodiments, the rate at which the one or more markers align with the starting point may correspond with the recommended pullback speed of the catheter. In some embodiments, the recommended pullback speed may be 0.5 – 15 mm / s, e.g., 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 mm / s. The recommended pullback speed may be a preprogrammed value. In some embodiments, the processor may prompt the user to enter the recommended pullback speed and receive the pullback speed from the user, and can provide audible feedback such as an alarm, and / or request to speed up or slow down. In some embodiments, the processor may receive another indication from the user to end the movement dictation. Similarly, the indication to end the movement direction may be received from the input device. In some embodiments, the system-to-operator interaction output may include an annotated IVUS image. During a movement of the catheter body, the IVUS catheter system may capture one or more IVUS images. The processor may calculate a movement of the catheter body and annotate the IVUS images to indicate a longitudinal position of the catheter. The longitudinal position may be a position of the distal tip of the catheter relative to a point of insertion or to the starting anatomical point. In some embodiments, the processor may annotate the IVUS image to include a corresponding longitudinal position of the catheter at the time the image is captured. Annotations may be provided in real-time or added retrospectively. According to some embodiments, the processor may annotate the IVUS image to include a speed of the catheter. In one embodiment, a system-to-operator interaction process for detection of a manual longitudinal movement of an IVUS catheter according to one embodiment. In some embodiments, the process may include more or fewer steps. In some embodiments, one or more of the steps of process may be performed in a different order or simultaneously with respect to one or more of the other steps of process. In a system-to-operator interaction embodiment, an operator performing a pullback may be paced by a series of indications from the system representing an intended uniform progress of the observable markings on the catheter past a fixed point. In the system-to-operator embodiment the system guidance can be thought of as guiding pullback speed, similar to how a metronome guides the pace of a beat for a musician playing music. A target pullback rate is programmed in the system (or selected from pre-configured values), e.g., 1-20 mm / sec (e.g., 1, 2, 5, 10, 12, 15, 20 mm / sec and values and ranges therein), and the system provides pacing indicators while the operator performs the pullback (or a push-forward) so that the operator may adapt the translation rate as well as judge the intended rate was achieved. In this embodiment the mapping between image capture time and longitudinal position can be aligned and / or synchronized according to the intended translation rate. In one embodiment, the user may reject a spatial alignment orsynchronization and re-attempt the process. In various embodiments, an operator-to-system interaction involves the user inputting information to the system. An operator-to-system interaction process for detection of a manual longitudinal movement of an IVUS catheter may be provided according to one embodiment. In some embodiments, the operator-to-system interaction process may include more or fewer steps. In some embodiments, one or more of the steps of process may be performed in a different order or simultaneously with respect to one or more of the other steps of process. In various embodiments, the input may be received through a user interface or via the input device. For example, the user may provide a keyboard, mouse, touch-screen, or other input to initiate a movement dictation. In some embodiments, the indication may be a speech input, which the processor may receive via the input device. In some embodiments, the indication to start the movement dictation may include an anatomical point which may be a starting point or a reference point. Anatomical points may include an anatomical structure such as an anastomosis, a point relative to a radiopaque structure, a proximal end of a calcified lesion, a distal end of the calcified lesion, etc. In several embodiments, the user may dictate or enter one or more anatomical points to the IVUS catheter system. The operator-to-system interaction process may move to step where the processor may receive a user input. The catheter system may include an input device. The input device may be a microphone, a tactile input device, or a camera. The processor may receive an input from a user, such as a voice-input, via the input device. In some embodiments, the input may be a words or sounds indicating a pullback speed. For example, the input device may be a microphone. The user may provide input indicating the pullback speed, and the processor may receive the information and calculate a pullback speed. In some embodiments, the user input may provide a reference point input. A reference point input may associate a current longitudinal position relative to an anatomical point such as a radiopaque structure, a proximal end of a calcified lesion, a distal end of a calcified lesion, or any point where the catheter may be positioned. For example, the input device may be a microphone, and a physician may provide a marker input indicating that a first marker of the one or more markers is aligned with an anatomical point, such as a boney fiducial. At the same time, the distal tip of the catheter may be positioned at a distal end of a calcified lesion. For example, the physician may say “one,” and the processor may receive the speech input via the input device. The user may begin to move the catheter in the proximal / distal direction. According to some embodiments, the user may provide one or more pacing inputs indicating that subsequent markers are disposed at the reference point, and the processor may receive the pacing input(s). The one or more pacing inputs may be entered through the input device and may be touch inputs, speech inputs, mechanical inputs, etc. Based on the pacing inputs, the processor may calculate a longitudinal movement distance based on the one or more pacing inputs and the known distance between the one or more markers. Returning to the example above, the user (e.g., operator, physician, medical personnel) may move the catheter in a proximal direction (e.g., perform a pullback maneuver) after providing the reference point. At the beginning of the pullback maneuver, a first marker of the one or more markers may be aligned with a boney fiducial point. As the physician pulls the catheter in the proximal direction, the physician may provide a second input, such as saying “two,” when a second adjacent marker is aligned with the boney fiducial point, which may be received by the processor via the input device. Themovement may continue, and the physician may provide subsequent user provided inputs indicating when a third, fourth, fifth, ... nth marker are aligned with the boney fiducial. Based on the user’s provided inputs, the processor may calculate a position of the catheter and imaging core during the pullback maneuver. In one embodiment, an operator- to-system interaction process for detection of a manual longitudinal movement of an IVUS catheter according to one embodiment. In some embodiments, the operator-to-system interaction process may include more or fewer steps. In some embodiments, one or more of the steps of process may be performed in a different order or simultaneously with respect to one or more of the other steps of process. In one embodiment of an operator-to-system interaction, the operator would provide input to the system regarding manual catheter translation progress during acquisition of the imaging series. For instance, a user may count aloud the catheter markers as they pass by a bony fiducial seen in fluoroscopy, e.g., “Start, One, Two, Three,” etc. with the audible input to a microphone. In this embodiment the spatial distance mapping between image capture time and longitudinal position would be an interpolated function based on the operator inputs. In one embodiment, the system may detect error conditions and reject the spatial measurement calculation. For instance, if missed repeated or out of order counts are detected, or if severely non-uniform counts are detected the system can reject spatial measurement and inform the user so they may repeat the action if desired. In one embodiment, translation progress indicators could be voice-command such as in the above example embodiment or another input interface mechanism such as buttons on a user-input device like a display screen, button, or foot switch. The ability to audibly indicate translation progress by unique counts / commands, such as spoken “Start, One, Two, Three,” etc. commands rather than a non-specific command likely improve accuracy and robustness. In one embodiment, non-specific progress indicators, such as spoken “Mark, Mark, Mark” indications, or footswitch taps, taps on the catheter body if for instance a haptic sensor is provided, etc. would be sufficient.

[0144] Fig.3 illustrates an ultrasound control (USC) board 300 according to one embodiment. The USC board 300 may be an expansion card that plugs into a workstation, such as the workstation 118. For example, the USC board 300 may be a daughter card that connects to a motherboard of the workstation (e.g., plug in via a PCIexpress (PCIe) slot). The USC board 300 may include a system cable interface 302, electronic isolation circuitry 304, a CIM communications and power interface 306, a field programmable gate array (FPGA) 308, a bidirectional analog ultrasound signal interface and radiofrequency (RF) multiplexer (MUX) 310, a receive signal amplifier (Rx Amp) 312, an analog-to-digital converter (ADC) 314, a digital-to-analog converter (DAC) 316, a transmit signal filter 318, and / or a transmit signal amplifier 320.

[0145] The workstation 118 may provide power to the USC 300, e.g. via the PCIe slot, via a 6-pin, 8- pin, or 12-pin power cable. The workstation may provide bidirectional data transfers with the USC 300 through the expansion slot, e.g. the PCIe slot. The USC board 300 may be electronically connected to the catheter interface module (CIM), e.g. via a system cable and a system cable interface 302. The USC 300 may provide power to the CIM from the CIM communications and power interface 306 via the system cable. The system cable may also provide bidirectional communications between the USC board 300 and the CIM. The USC 300 and the CIM may transmit high frequency (5to 90 MHz) analog ultrasound signals at a low-voltage (<5Vpp) bidirectionally via the system cable. The bidirectional communications between the USC 300 and the CIM may use a custom protocol that includes error checking. In some embodiments, circuitry 304 may be provided to isolate electrical signals between the USC 300 and system cable, which is illustrated in Fig.3 with a dotted line.

[0146] The USC 300 may include a Field Programmable Gate Array (“FPGA”) 308. The FPGA may direct transmit and receive signals between the components of the USC 300 and at least one processor of the workstation 118. The FPGA 308 may support high speed digital data transfers between the components of the USC 300 and / or the workstation 118. The FPGA 308 may support high speed transfers between the USC 300 and the workstation 118 via a PCIe interface. The FPGA may provide data transfers between itself and one or more subcomponents of the USC 300 at a rate equal to or greater than 500 megasamples per second (Msps). For example, the FPGA 308 may receive signals from the ADC 314 and / or transfer to the DAC 316 at a rate equal to or greater than 500 Msps. In some cases, the FPGA 308 may provide high-speed data transfers between itself and the subcomponents of the USC 300, such as the ADC 314 or the DAC 316 via a serial interface (e.g., JESD204B serial interface) or a Low Voltage Differential Signaling (LVDS) standard, respectively.

[0147] The FPGA 308 may control the timing of transmit signals (e.g., beginning of ultrasound pulse- echo events) and receive signals (e.g., echo signals received from the IVUS catheter). In some implementations, the FPGA 308 may control the switching of ultrasound transmit and receive signals (“Tx / Rx selection”) of the RF multiplexer 310 (MUX). The RF multiplexer 310 may direct analog signals to and from the CIM through the system cable. In some embodiments, the CIM may include a corresponding multiplexer that is placed in electrical communication with the RF multiplexer 310 via the system cable. The CIM multiplexer may act as a corresponding demultiplexer and be temporally timed to receive or transmit signals from the RF multiplexer 310 through the system cable. For example, as described below, the system cable may include at least one single balanced differential shielded twisted pair wire, and the RF multiplexer 310 may direct analog signals and receive analog signals via the wire.

[0148] The DAC 316 may be supplied a digital signal with a transmit bit depth from the FPGA 308 and convert the digital signal to an analog signal. The digital signals may be provided to the DAC 316 using LVDS. The transmit bit depth may be at least 10 bits, and / or at least 14 bits. In some embodiments, the transmit bit depth may be between 14 bits and 16 bits. The high bit depth and corresponding high dynamic range of the DAC 316 enables subsequent amplification of transmit waveforms with high signal amplitude precision and control of the signals spectral frequency content supporting high image spatial resolution and maximum signal to noise image quality. In one embodiment, spectral refers to several, or a spectrum of, frequencies. For example, the bit depth of the DAC 316 may enable subsequent amplification of a transmit signal by a coupled transmit power amplifier in the CIM. Advantageously, the FPGA-driven 308 DAC 316 can provide a high dynamic range and increased control of transmit spectral content. This precise control of analog transmitted waveforms to the IVUS transducer fully excites the available spectral contentof the acoustic transducer generating maximum transmitted signals and waveforms with short duration for high image spatial resolution.

[0149] At the output of the DAC 316 a transmit signal filter (Tx filter) 318 may modify the analog transmit signal. The Tx filter 318 may smooth low voltage transmit signals between samples. The Tx filter 318 may also eliminate spectral images of the transmit signal centered at harmonics of the DAC 316 sampling frequency. A transmit amplifier (Tx Amp) 320 may amplify the transmit signals. The transmit amplifier 320 may amplify transmit signals without exceeding 5V for transmission via the system cable at least according to some embodiments.

[0150] The analog transmit signal may pass through the CIM to a transducer of the IVUS catheter as described below, and the transducer may receive at least one pulse echo backscatter, i.e. a receive signal, generated in response to the transmit signal. The receive signal may pass back through the CIM as described below and return to the USC 300 via the system cable interface 302. The MUX 310 may direct the receive signal to a receive signal amplifier 312 (Rx Amp). The Rx Amp 312 may amplify the receive signal to meet the input voltage requirements of the ADC 314, e.g.5V or less. The ADC 314 may convert the receive signal from an analog signal to a digital signal and provide the converted receive signal to the FPGA 308. The FPGA 308 may then provide the receive signal to the workstation 118. In some embodiments, the FPGA 308 may receive 16-bit samples from the ADC 314 using 2 Lanes at 5 Gbps per lane using a serial interface, such as a JESD204B serial interface. Oversampled Analog to Digital Converter (ADC)

[0151] In some embodiments, the ADC 314 may be oversampled. The oversampled ADC 314 may improve image quality by providing a higher signal-to-noise ratio (SNR). In some embodiments, the sample rate of the ADC 314 may be about 500 Msps. The ADC 314 may sample the analog signal from the Rx Amp 312 with a receive bit depth of 16 bits per sample. The sample rate of the ADC 314 may be significantly higher than the absolute spectral bandwidths expected with IVUS transducers in the frequency range of 5 to 90 MHz.

[0152] Oversampling a signal significantly higher than the Nyquist rate can improve the quantization SNR and conversion resolution of a band limited signal, particularly when noise is uncorrelated and has uniform power spectral density. Improvement in quantization SNR in decibels may be defined by Equation 1 shown below. (1) SNR=6.02N+1.76+10log10(fs / 2BW);

[0153] In Equation 1, “N” represents the effective bit depth of the measurement. “fs” is the sampling frequency of the ADC 314 in MHz. BW is the bandwidth in MHz of the signal of interest. In one embodiment, oversampling may be by at least a factor of two (e.g., 2x, 3x, 4x, 5x, 10x, 15x, 20x or more, including values and ranges therein). Oversampling by at least a factor two above the Nyquist frequency may improve the SNR by 3.01dB. Oversampling can also reduce the requirements of an analog anti-aliasing filter (not shown) ahead of the ADC 314 with a sharp cut-off frequency. Larger and longer digital spectral filters with steep roll-off characteristics may be more easilyimplemented in the digital domain of the FPGA 308 after conversion of the receive signal by the ADC 314. In some embodiments, SNR may be increased by digitally band-limiting the receive signal bandwidth for the selected catheter based on the properties of the transducer. For example, the receive bandwidth may be further limited with bandwidths of transducers that are less than 85 MHz further improving quantization SNR.

[0154] As an example, in one embodiment for signals from a broadband cabled transducer design with 90 MHz bandwidth the oversampling factor is ~2.78 providing a significant increase of ~4.4 dB improvement in SNR using an oversampled ADC design. Greater than 4.4 dB SNR gain is possible with bandwidths less than 90 MHz as band-limiting can be implemented with temporal decimation to a final data rate. Catheter Interface Module

[0155] a catheter interface module (CIM) 400 according to one embodiment. The CIM 400 may be placed in electronic communication with an ultrasound control board (USC), e.g. the USC 300, and a workstation, e.g. the workstation 118. In some embodiments, the CIM 400 may connect with the USC 300 via a system cable as described herein. The CIM 400 may be placed in electrical and mechanical communication with a proximal end of an IVUS catheter. In some implementations, the CIM 400 may connect to a proximal end of an IVUS catheter via a proximal connector hub 116. The CIM 400 may rotate the imaging core 104, provide transmission and reception of ultrasound signals through electrical wires, and provide data transfers with the IVUS catheter.

[0156] The CIM may include an ultrasound transceiver 402, an FPGA 404, an impedance matching network 406, a motor 408, and / or a hollow bore slip ring 410. The FPGA 404 communicates with the USC and manages a set of functions of the CIM 400. In some embodiments, the FPGA 404 may control the ultrasound transceiver to generate transmit signals and process receive signals. The FPGA 404 may also control the rotation of the imaging core of the IVUS catheter by the motor 408.

[0157] The ultrasound transceiver 402 may include a CIM multiplexer 412, a transmit amplifier 414, a transmit / receive switch 416, an analog front end (AFE) receiver 418, and a time gain control digital-to-analog converter (TGC DAC) 420 according to some embodiments. The CIM multiplexer 412 may receive transmit signals from the USC and direct receive signals along a system cable to the USC. The CIM multiplexer 412 may be paired with a USC multiplexer, e.g. the multiplexer 310, to direct transmit and receive signals over the same wires within a system cable connecting a USC and the CIM 400. Transmit Amplifier

[0158] The transmit amplifier 414 (labeled “Pwr Amp” in Fig.4) may be a high performance, linear, high-power amplifier. A detailed version of the transmit amplifier 414 according to one embodiment is shown in Fig.5. The transmit amplifier 414 may receive low voltage (< 5 Vpp), high fidelity, linear transmit waveforms from the CIM MUX 412 and provide precise amplification to drive the transducer in the imaging core where catheter total continuous lengths may exceed 177 cm, or alternatively can be beneficial for any length catheter. In various embodiments, high- power may refer to output power levels >= 8 Watts instantaneous peak power (e.g., 8W, 9W, 10W, 12W, 15W, 20Wor more including values and ranges therein), In one embodiment, a linear high-power transmit amplifier is configured to amplify transmit signals. The transmit amplifier 414 may provide output power levels >= 8 Watts instantaneous peak power into a 50 ohm load and sized appropriately for maximum catheter length with sizing compensating for greater signal losses associated with any catheter length and particularly beneficial for longer electrical cables than currently provided in IVUS catheters. Direct current (DC) power may be provided to the transmit amplifier 414 using one of 20, 25, 30, 35, 40, 45, & 50 Vdc (e.g., with 42.5 Vdc used as the voltage for several embodiments). The operating frequency range of the transmit amplifier 504 may support the range of frequencies required for the available catheters and the clinical application. A broad range is used in several embodiments, for example a range of >= 5 MHz to <= 90 MHz is (such as 5-30 MHz, 30-60 MHz, 60-90 MHz and overlapping ranges therein), using, in one embodiment, the -3dB levels relative to the peak signal strength in the passband of frequencies.

[0159] In several embodiments, any suitable amplifier class may be employed however the linearity of the amplification from the arbitrary waveform input signal into transmit amplifier 414 may be helpful for maintaining high fidelity and avoiding spectral distortion which degrades the axial spatial resolution in the image. The transmit amplifier 414 may be a Class “AB” amplifier with power efficiency above 50%, low cross-over distortion, and high linearity. In some embodiments, the transmit amplifier 414 may include additional bias circuitry so during the positive and negative signal excursions, the amplifier 414 smoothly switches between operating in Class A and B modes, and the bias level may be adjusted dynamically as a means to disconnect the amplifier during receive operation. Other amplifier classes may also be employed but have various design and performance tradeoffs. In some embodiments, the transmit amplifier 414 may be a class “A” amplifier which provides excellent linearity as the output transistors are always conducting but have poorer power efficiency typically below 50%. In some embodiments, the transmit amplifier 414 may be a class “B” amplifier. Class B amplifiers may be more power-efficient, however the switching between transistors may create cross-over distortion which may degrade spectral shape and image quality.

[0160] The embodiment of the transmit amplifier 414 shown in Fig.5 includes a balanced input receiver (BIR) stage 502 to drive the input of the balanced class AB amplifier driver 504. After a 1:2 impedance transformer 506, the transmit signal may be amplified by the power MOSFETS 508 configured as a class AB amplifier to produce a high-fidelity transmit waveform delivered to the catheter. Selectable Impedance Module

[0161] The CIM may include an impedance matching network 406. In some embodiments, the FPGA 404 may select a matching network from the electrical impedance matching network 406 specific to the single catheter connected to the CIM. The “SPI – module selection” from the FPGA 404 may select the impedance matching network using a standard serial peripheral interface (SPI). Maximum power delivery from the transmit amplifier 414 may occur when the complex electrical impedance directed into the catheter is approximately equal to the complex conjugate of the impedance directed into the transmit amplifier 414. The process of matching the complex electrical impedancedirected into the catheter to the complex conjugate of the impedance directed into the transmit amplifier 414 may be referred to as conjugate matching. The impedance matching network 406 may perform conjugate matching. The impedance matching network may transform the complex input impedance of the catheter to the output impedance of the power amplifier with minimal or no loss. Advantageously, the selected impedance may use lossless reactive components to transform the electrical impedance of the catheter to a value more closely matched to an optimal operating impedance of the transmit power amplifier 414 to maximize power delivery to the transducer near the end of the catheter and maximize SNR.

[0162] Fig.6 illustrates an impedance matching network 406 according to one embodiment. The CIM FPGA 404 may select a single electrical impedance (Z) matching network, “Z Matching Network #,” e.g., Z Matching Network 0, Z Matching Network 1, etc. The FPGA 404 may select the single electrical impedance based on one or more characteristics of the catheter. In some embodiments, the CIM FPGA 404 may detect or receive the catheter characteristics or identification (ID) number from the IVUS catheter, e.g. via a non-volatile memory of the IVUS catheter. The selectable impedance matching network 406 can include many individual networks depending on the desired size of the circuitry in the CIM. For example, the impedance matching network may include up to eight (8) networks supporting up to eight different catheters, e.g. the impedance networks numbers 0-7 in Fig.6. The impedance matching network 406 may support multiple catheters for clinical applications such as peripheral vascular and coronary vascular imaging. More than one impedance matching network supports a family of different catheters that may be operational with single deployed system in the clinical environment.

[0163] In some embodiments, the impedance matching network 406 may be comprised of a series and parallel reactive component(s) on each port and a broadband transformer between the ports to allow flexibility and support for optimally matching a wide range of catheter complex input impedances. The arrangement of subcomponents of the impedance matching network 406 may provide flexibility in the type of impedance matching performed, provide tradeoffs in performance such as the degree (closeness) of matching and overall spectral bandwidth. In some embodiments, the transmit amplifier 414 can operate over a wide complex load impedance range, such as 50 + / - 20 ohms and 0 + / - 30°, allowing the matching network 406 for a specific catheter to be implemented with considerations for ease of construction and maximum overall spectral bandwidth. The output of the transmit amplifier 414 may be about 50 ohms according to some embodiments. In some embodiments, other impedances may be used for optimal matching and power transfer.

[0164] An impedance may be selected from the impedance network 406 with low parasitic reactance, low loss, low noise, and bidirectional transmit / receive operation and with support for the maximum transmit voltage output from the power amplifier. Returning to the example above, 8 matching networks may be independently selected by an RF relay tree employing 8 double-pole double throw (DPDT) latching relays. Four controls may select the desired path and isolate both the input and output ports of all matching networks. Latching relays may be employed to minimizepower and noise during operation, allowing the appropriate path to be selected when the catheter is connected to the system and remain active until a different catheter is connected. Analog Front End Receiver

[0165] The analog front end (AFE) receiver 418 may receive the receive signal (e.g., a plurality of pulse echo signals) from the IVUS catheter. In some cases, the AFE receiver 418 may receive the receive signal via the impedance matching network 406. A more detailed version of the AFE receiver 418 according to one embodiment is shown in Fig.7. The AFE receiver 418 may include a low noise amplifier (LNA) 702, a variable gain amplifier (VGA) 704, a transmission line (TL) balun 706, and a Balanced Differential Driver (BDD) 708. The AFE receiver 418 may amplify the receive signals to maximize SNR. The AFE receiver 418 may provide maximized, low voltage (< 5 Vpp) balance differential signals to the CIM multiplexer 412 for transmission to a workstation and / or USC. In various embodiments, the low noise amplifier (LNA) may be a commercially available or custom design amplifier with at least a gain of 20 dB with a noise figure less than or equal to 1.2 dB over a frequency bandwidth of 5 to 90 MHz.

[0166] Ultrasound transmitted waveforms and received echoes may be attenuated as they travel through the catheter polymer jacket and patient anatomy. The level of attenuation is dependent on many factors including (1) transmit and receive sensitivity of the transducer, (2) the quality of the electrical match in the impedance matching network, (3) the round-trip distance between the transducer and the target of interest, (4) the frequency of the waveform (higher frequencies attenuate more), and (5) the acoustic impedance of the target of interest for the anatomy of interest.

[0167] In some embodiments, the FPGA 404 may control the AFE receiver 418 and / or its subcomponents. For example, within a transmit / receive pulse-echo event, the FPGA 404 may apply a time-dependent gain to the VGA 704 through the TGC DAC 420. This variable amplification may be applied to adjust for the attenuation characteristics per line applied in an image to create the full 360 degree image on the display as the imaging core rotates. The workstation 118 and / or the USC may provide a unique table of TGC gain values. For example, the TGC table may be stored in a non-transitory memory of the CIM and provided to the FPGA 404. The TGC table may include a plurality of TGC gain profiles for a particular pulse-echo event based on one or more characteristics of specific catheters and / or imaging scenarios. In some embodiments, the TGC table may be a sparsely populated table. The FPGA 404 may interpolate between these gain values in the TGC profile to generate a TGC profile that provides a smooth varying ramp based on distance from the transducer face which is delivered to the TGC DAC. The gain through the AFE may be between >= 10dB to >= 42dB. The gain may avoid electronic amplifier saturation and maximize signals far from the acoustic transducer to avoid blurred / smeared spatial resolution and provide for increased axial and azimuthal resolution, respectively.

[0168] The speed of the FPGA 404 is significantly faster than the host communication rate. Advantageously, the FPGA 404 and the TGC DAC 420 allows the system to reduce load on a workstation processor thereby increasing the processing speed of the workstation and increasing the overall efficiency of the IVUS system.In turn, the workstation can provide a faster, more responsive, and more real-time graphical user interface (GUI). In one embodiment, this design avoids having the workstation processor provide many gain values for each line in the image. Hollow Bore Slip Ring and Patient Electrical Isolation

[0169] The hollow bore slip ring 410 may provide continuous electrical ultrasound signals to and from the wired transducer in the catheter. For example, the hollow bore slip ring 410 may provide continuous electrical ultrasound signals to and from the wired transducer to a stationary coax cable in the CIM. In some embodiments, a rotary transformer, conductive liquid coupling, and other designs may be used to couple rotating electrical signals to stationary connections. In several embodiments, use of a mechanical slip ring may provide advantages in frequency response with broader bandwidth, insertion loss, and / or use of medical device-approved materials to provide RoHS compliance; however, potential issues of signal noise and longevity may need to be addressed. Use of redundant brushes and rings are employed, in some embodiments, to both reduce signal noise due to variable contact resistance and provide the desired longevity. In one embodiment, the slip ring may be comprised of >= 6 rings allocated equally between a coax center conductor and shield, with >= 2 brushes per ring. Creating redundant brush and wire connection to each electrical wire needed in the signal path to the transducer improves signal and image quality in several embodiments. A non-conductive coupling shaft connected to the slip ring 410 and isolating circuitry provides a patient isolation barrier across the components shown in Fig.7 with the vertical dotted line to ensure patient safety. A preferred barrier according to one embodiment is provided as a Type CF applied part, cardiac floating, per IEC60601 Medical Electrical Equipment standards. FPGA Motor Control

[0170] The FPGA 404 may synchronize timing of the motor rotation and ultrasound (US) pulse-echo events. The FPGA 404 may control the velocity of the motor 408. In some embodiments, the motor 408 may be a brushless direct current (BLDC) motor. The FPGA 404 may control shaft rotation of the motor 408 through a feedback loop using position data from the motor’s encoder for programmable (variable) rotation speeds up to 3600 and 4000 rpm with the catheter connected. The coupling shaft, hollow bore slip ring, and catheter present torque loads to the motor that may be >= 20mNm. According to several embodiments, the motor provides continuous torque to the catheter with smooth velocity operation and minimum torque ripple to minimize image distortion (NURD), provide high electrical to mechanical power conversion efficiency, such as >= 85%, to minimize power dissipation in the CIM, and provide long operating life. In one embodiment, the motor is a brushless direct current (BLDC) motor containing 4 poles for high efficiency and low torque ripple. The motor may also be a 2 pole BLDC, or brushed motor. The encoder can provide high resolution to maintain smooth velocity control at low speeds <600 rpm and is, for example, a quadrature encoder providing a quadrature resolution of at least 16,384 counts per revolution.

[0171] The CIM FPGA 404 may provide an architecture with an angular velocity control algorithm to allow the speed of rotation of the transducer to be both continuously controlled within a single imaging frame and acrossframes to prevent long term drift relative to the US line operation. Fig.8A illustrates a motor control algorithm 802 according to one embodiment. The motor control algorithm 802 may synchronize the angular velocity control within the CIM with the transmit and receive events initiated by the USC 300.

[0172] In some embodiments, an ultrasound synchronization signal may be sent by the USC 300 or the workstation 118, which may be received by the CIM, e.g. at the FPGA 404 or at the motor control unit 422. A “US Sync event” as used herein shall refer to an ultrasound synchronization signal being sent. The FPGA 404 may determine the exact rotational position of the motor for each US Sync event. The determined motor position for a given “US Sync” signal may be compared to the motor position for a previous rotation to determine whether there is a positional error between the actual and desired motor positions. If a positional error is present, the positional error may be filtered to reduce jitter and quantization error. The positional error may be used to determine a new velocity setpoint for the motor 408 to reduce the positional error after the next rotation. This position monitoring and velocity adjustment may occur every rotation and operate over a wide range of motor 408 rotations per minute (rpm), e.g. from about 300 rpm to about 4000 rpm.

[0173] In some embodiments, the motor control unit 422 may include both velocity and current proportional, integral (PI) control loops which dynamically track and control the motor velocity. The motor 408 may include a high resolution position encoder 424. For example, the position encoder 424 may have a resolution of 16,384 counts / revolution or higher. The high-resolution encoder 424 may support accurate velocity control in particular for lower velocities. In some embodiments, a motor control loop cycle time for tracking the motor velocity may be less thanor equal to 102.4 microseconds ( sec). The FPGA 404 may filter velocity estimates extracted from the high resolutionposition encoder feedback to reduce quantization error. In some embodiments, the FPGA 404 may perform field oriented control (FOC) of the motor 408 current to provide higher operating velocity as well as quieter and higher efficiency operation. Advantageously, the incorporation of real-time feedback of the motor encoder 424 values by the motor control algorithm 802 supports the ability to: (1) avoid rotational image drift and (2) target higher line density sampling for angular subsections of an image, which in turn improves image quality.

[0174] In some embodiments, the algorithm 802 may also provide for higher image line densities to be generated in particular subsections of an image by slowing down the rotation and then speeding back up for the remaining subsections of an image to maintain a desired frame rate. Examples of such subsections are illustrated in Figure 8B. Subsection A in Figure 8B may be selected to improve the angular pulse-echo sampling of a vessel dissection where the flap may be very thin and difficult to clearly see in the image. A greater density of image lines can improve visualization. The imaging of other anatomy may also be improved with this technique. A different subsection B may be used to image blood flow with better image quality by increasing the line density. When targeting higher line density sampling for angular subsections of an image, knowledge of the position of the rotating shaft for each transmit event is necessary to adequately reconstruct the image. The high-resolution position encoder 424 can be used to capture the shaft position on every transmit and receive event. The positional information for each transmit and receiveevent can be transferred from the CIM FPGA 404 to the USC 300, and delivered to the memory of the workstation along with the pulse-echo imaging data to support reconstruction of the image.

[0175] Advantageously, the motor control algorithm may prevent rotational drift and improve IVUS image quality. Rotational drift may occur when transmit and receive events are not precisely synchronized with the directional position of the imaging core as differences in the clock in the CIM and USC will create images that drift over time. Drift can cause stationary objects in the human vessel to slowly move around the circular IVUS image, which is undesirable to the user. The algorithm may also advantageously provide precise control that would otherwise be unavailable if the clock source for signals in the USC 300 and workstation are different than the source for the CIM.

[0176] In some embodiments, the FPGA 404 may control power supply to the components of the CIM. For example, the FPGA 404 may control tiles of multiple voltage supplies for circuitry originating from the 48V supply from the USC “P48V, GND, Power Tiles.” In some embodiments, the FPGA 404 may monitor the electrical integrity of components of the IVUS system 100. For example, the FPGA 404 may determine an electrical integrity of the System Cable through a presence indication and bidirectional fault signaling. A fault condition can be generated by the CIM or USC providing coordinated shutdown of ultrasound and motor operation when a system fault is detected on either side.

[0177] In some embodiments, the IVUS catheter may include a non-volatile memory chip that stores catheter identification information. The CIM 400 may authenticate the IVUS catheter based on the catheter identification information. In some embodiments, the CIM 400 may collect and store unique characterization data for the specific transducer in the catheter. The FPGA 404 may control two-way communications with the 1-wire non-volatile memory chip within the catheter proximal connector hub 116 including catheter identification, security encryption algorithms, and catheter-specific data storage & retrieval. CIM and Workstation USC Sequencer Controller

[0178] The CIM FPGA 404 may control general communications and data transfers for CIM operation. The FPGA 404 may select the direction of signal flow through the system cable by controlling the multiplexer (MUX) 412 in a coordinated manner with the USC MUX. In some embodiments, the CIM FPGA 404 may control setup of ultrasound transceiver 402 timing. During a transmit cycle, a transmitted signal may be emitted from the CIM. The transmit signal may include voltage levels defined by the 10-bit or higher resolution DAC within the USC 300 according to some embodiments. The FPGA 404 may control of biases voltages for the transmit power amplifier 414 and the transmit / receive switches “Tx / Rx Switch.” During a receive signal cycle, the FPGA 404 may control digital data input to the time gain control DAC 412 “TGC DAC.” In some embodiments, the FPGA 404 may select a programmable TGC profile. The time gain control DAC 412 may increase the amplification of received echo signals as a function of increasing depth of penetration per pulse-echo event. The CIM FPGA 404 may also select a receive filter using a communication transceiver (“Comm Xcvr”).

[0179] Some conventional rotational IVUS imaging devices may have limited image quality because they use a single transmit waveform per image line. The single transmitted waveform must be selected to eithermaximize axial spatial resolution at the sacrifice of limited / shallow penetration into the targeted vessel and tissue, or compromise with worse axial spatial resolution and achieve a bit more depth penetration for the displayed image. Some rotational IVUS transmitters may have implemented circuitry with a simple unipolar or bipolar pulser and a single transmitter output voltage. A greater number of pulses or cycles within a transmit waveform can provide more energy to increase depth penetration, but the received echo is much longer, decreasing axial spatial resolution.

[0180] Embodiments described herein provide the ability to use more than one transmit waveform per image line. The CIM FPGA 404, the USC FPGA 308, and the workstation 118 may execute a transmit / receive control sequence algorithm using a Master Sequencer Controller. The transmit / receive control sequence algorithm may provide increased lateral and axial resolution. The transmit / receive algorithm may select from up to 8 transmit waveforms with different specifications for each waveform.

[0181] In some embodiments, the at least one processor of the workstation 118 may instruct the USC FPGA and / or the CIM FPGA 404 to generate the transmit waveform(s). In some embodiments, the USC FPGA may be a “master” FPGA which receives transmit and receive instructions from the at least one processor of the workstation 118, and the CIM FPGA 404 may be a “slave” FPGA which receives instructions from the USC FPGA for the generation of transmit signals and reception of receive signals. The master USC FPGA and slave CIM FPGA 404 may control the timing and selection of transmit and receive parameters. An example master / slave FPGA arrangement according to one embodiment is shown in Fig.9. The master USC FPGA 308 and slave CIM FPGA 404 may be temporally aligned with a synchronization signal through a communication link of the system cable. The at least one processor of the workstation 118 may instruct the USC FPGA 308 and CIM FPGA 404 to perform the transmit / receive sequence. In some embodiments, the at least one processor may select transmit and receive parameters and timing for each of N lines in a single ultrasound image and instruct the FPGAs based on the parameters and timing before imaging starts. In some embodiments, the at least one processor may provide parameters on a line-by-line basis to improve image quality. Advantageously, the master FPGA and slave FPGA may reduce the load on the processor of the workstation 118. In turn, the at least one processor may have more bandwidth to analyze the receive signals to generate IVUS images in real-time, perform analyses on said images, and provide a more reactive user interface. Thus, the master FPGA and slave FPGA improve the functionality of the IVUS system 100.

[0182] Embodiments described herein provide high axial resolution at a larger range of depths. The sequence control algorithms described herein enable the use of high axial spatial resolution for pulse-echoes closest to the rotating transducer and an additional one or two different waveform designs that increase penetration farther from the transducer, deeper into the blood, vessel and / or tissue. The latter one or two waveforms, referred to herein as “deeper” waveform designs, may be longer waveforms with narrower spectral bandwidths compared to the former “shallower” designs. In some embodiments, the waveform design(s) can be unique coded excitation designs with broader spectral bandwidths where received echoes are decoded after using coded transmit waveforms. These coded designs can maintain the high axial spatial resolution for all deeper depths in the image, providing greater penetrationas the energy in the transmitted waveforms is significantly greater with broad / wide received spectral bandwidth. In other embodiments, the coded designs can trade-off some penetration and select a fixed spectral content at higher frequencies. This maintains high axial resolution however has the additional benefit of improved azimuthal, or lateral, resolution.

[0183] More specifically, the at least one processor may determine transmit and receive parameter(s) for each line in an N-line image and instruct the USC FPGA 308 and CIM FPGA 404 to generate transmit signals and collect receive signals at an instructed timing based on the transmit and receive parameters. The transmit and receive parameters may include a number of transmit and receive events for each rotation; a number of transmit waveform(s) per line; one or more receive filters for processing backscatter signals from each transmitted waveform; the timing and relative timing of transmit and receive signals; and a process for combining two or more interleaved transmit and receive events within a single line.

[0184] In some embodiments, the transmit and receive sequence may be provided to the USC FPGA 308 and the CIM FPGA 404 as a transmit / receive event matrix. Simple and complex multi-line ultrasound sequences can be implemented and changed via the at least one processor of the workstation 118 without the need to reconfigure, reprogram or modify hardware components. In some embodiments, the transmit and receive sequence may include operational codes that allow for starting, stopping, adding delays, looping, as well as selecting a specific transmit and / or receive configurations. These operational codes may be interpreted and executed by the FPGAs to achieve the desired sequence.

[0185] A Transmit (T) / Receive (R) event matrix according to one embodiment is shown below in Table 1. Table 1 - Transmit(T) / Receive (R) Event Matrix

[0186] Image line numbers 1 to N are shown along the x -axis represented by the first # in the notationThe number of transmit / receive events 1 to Ei per image line number are shown along the y-axis and represented by the second # in the notation “T / Rwhere Ei represents the last event per line. Transmit and receive event parameters may include transmit waveform, transmit start time, transmit end time, receive start time, receive end time, receive filter set, etc.

[0187] Example transmit and receive time interleaved sequences are illustrated in Figs.10A - 10E and Figs 11A- 11C. Figure 10A illustrates an example sequence of N image lines (L1to LN) in clockwise rotation that areprocessed to create a circular image with a display depth of distance R2from the exterior surface of the IVUS catheter jacket material. The number of lines and space between the lines, i.e. the time in between transmit signals, may be established based on the diffraction-based spatial resolution of the image determined by the transducer design and one or more characteristics of the transmit signal(s) and received signal(s). Figure 11A illustrates an example transmit pulse Ta 1102. The example transmit pulse Ta may be shorter than the distance to the exterior surface of the catheter jacket. Figure 11A also illustrates an example backscatter signal converted to a detected received amplitude signal 1104 as a function of the distance from the ultrasound transducer surface. The received amplitude signal 1104 modulates the brightness on a display device. The horizontal axis of Fig.11A may be an axial distance. Distance (r) of a backscatter signal may be equal to (c)(t) / 2 where “c” is the speed of sound and “t” is time to backscatter signal is received. In some embodiments, the length of a receive time may be based on a target axial depth associated with a transmitted signal. Figure 11B illustrates a transmit pulse Tb 1106 and another example of a detected received amplitude signal 1108. The transmit pulse Tb may have an increased length to provide more energy and more penetration into the blood, vessel, and tissue. The length of the transmit signal Tb may longer than the distance to the catheter jacket exterior as shown or may be shorter than the distance to the exterior of the catheter jacket.

[0188] Fig.10B illustrates the use of two different unique transmit and receive events implemented according to some embodiments with one set of event directions noted by lines Aiand another different set of event directions noted by line Li. Final display image lines Liare created by combining the echoes from events from Aiand Liper line i. In Fig.10B, a final displayed image of N image lines (L1to LN) may be created by combining received echoes shown in Figures 11A and 11B. The sequence of L and A line events are combined, two events per line. In this example, the receive signals from transmit pulse Ta are used for near field imaging to distance R1and receive signals from transmit pulse Tb are used for far field imaging past R1to distance R2. The sequence may begin by transmitting pulse Tb along a first line (L1) followed by a first receive period. Following the pulse of the Tb transmit signal, the target axial depth may be R2, and the system may receive backscatter signals time t =2(R2) / (c). Next, transmit pulse Ta may be delivered along A1(dashed-dotted lines in Fig 10B) juxtaposed very closely to a next line L2with a target axial depth of R1and a receive time window of t =2(R1) / (c). In this example, the second receive period associated with Ta may be much shorter than the receive period associated with Tb due to the difference in target axial depths (R1vs. R1). Next, a transmit pulse Tb is delivered along a next line L2followed by reception to distance R2.

[0189] This sequence may be repeated for each displayed line in the image (L2, L3, …. LN) with frames generated a real-time frame rates such as 30 and 60 Hz. Fig.10C illustrates the receive signals for both transmit pulses (Ta and Tb) for each of the lines (L1-LN, A1to AN). In Fig.10C, the dashed lines (connecting with the solid lines) indicate the range / distances of near field imaging received echoes and the solid lines indicate the range of the “far field” received echoes. In some embodiments, the receive signals for the first transmit pulse (Tb) and the second transmit pulse (Ta) may be combined. As can be appreciated by one skilled in the art, the lines upon which the second and subsequent transmit signals are generated and the associated receive signals are captured are not co-linear, however the angularspatial distance between the two different received echoes is small on the scale of imaging lines used in an image for an image highly sampled with sufficient number of pulse-echo events. Fig.10D and Fig.10E illustrate two different strategies for combining each group (Ai, Li) of receive signals into the final image lines to produce a plurality of image lines. In Fig.10E, the second received echoes shown as dash-dot lines in the figure may be substituted into the near field segment of the first receive signal from the first of paired transmit / receive events for each line L1to LN(shown with solid lines in the Fig.10E). The near field pulse echo data from lines A1-ANare substituted in the near-field range for the lines L1-LN, respectively.In another embodiments, the process illustrated in Fig.10D may analyze the amplitudes and phases of the neighboring or juxtaposed backscatter signals from pairs of Ailines only shown in Fig.10B for filling in the near field ranges. The receive echoes to fill-in the near field for a line Li is analytically calculated from two lines of echoes received from Ai-1and Ailines. The near field line may be calculated using range-dependent linear interpolation, or similar interpolation, between the two acquired receive signals (shown as dash-dot lines in Fig 10C). The interpolated backscatter signals (shown as dotted lines in Fig.10D) may be substituted into the near field segment of each line L1to LN. Detected amplitude blending using combinations of echoes from both the echoes from Ta and Tb transmitted events at and preceding the boundary at distance R1may also be implemented to avoid a potential discontinuity in the image at R1.

[0190] Fig. 11C illustrates an embodiment for using coded excitation on transmit and decoding on receive to generate higher energy waveforms that improve image quality for rotational IVUS images. The transmit and receive event in the above embodiment that used the transmit pulse Tb may be replaced with the new transmit pulse Tc 1110 for receiving echoes past a range of R1. This coded transmit waveform 1110 may have an effective length that is significantly longer than the transmit pulse Ta, possibly similar to the effective length of transmit pulse Tb, however the amplitudes and phases for each frequency component in the transmit pulse Ta are changed, or coded, to generate a broader bandwidth transmit pulse Tc 1110. The coded waveform 1110 may increase the total transmitted energy greater than transmit pulse Ta however preserve a broader spectral bandwidth and still achieve a similar and improved axial resolution as echoes received with transmit pulse Ta. The coded waveform 1110 may also increase penetration into the blood, vessel, and tissues. For coded transmit waveforms the phase of the signal may be nonlinear versus time in a unique way versus linear versus time. Fig. 12A illustrates a coded transmit pulse compared to conventional IVUS uncoded pulse. The top uncoded transmit signal shown as a dotted line has a -20dB pulse length of 0.26us while the middle coded transmit signal shown as a solid line has a -20dB pulse length of 2.39us. These two transmit pulses have a center frequency of 12.0 MHz and a -6.82dB relative spectral bandwidth of 51.8%. The envelope in decibels is shown in the bottom plot. This embodiment creates a 9.2 times longer pulse generating more transmitted energy to be received as acoustic echoes by the system. In various embodiments, pulses may be 1.5x – 20x times longer (e.g., 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 times and any ranges and values therein). Fig 12B shows the spectral content of these two transmit signal types. The spectral shapes are similar, however the coded transmit phase versus frequency shown as a solid line is nonlinear compared to the uncoded transmit phaseversus frequency shown as a dotted line is linear. Fig.12C shows the unique nonlinear signal phase versus time for the coded waveform in the top plot as a solid line compared to the linear signal phase versus time for the uncoded waveform in the dotted line. The corresponding instantaneous frequency change versus time is shown in the lower plot. The unique coded transmit with the solid line has a frequency that changes linearly with time compared to the uncoded transmit with the dotted line which is constant and does not change with time. In other embodiment the coded transmit may have a signal phase that varies nonlinearly with time and an instantaneous frequency that also varies nonlinearly with time. The rate of instantaneous frequency change can be increasing or decreasing versus time. In Fig. 12A and Fig.12C the rate of change is increasing from lower frequencies to higher frequencies, however the opposite may be designed.

[0191] After the echoes return to the transducer, the unique phase encoding may be reversed by decoding with the opposite phase profile versus time to generate a received short duration pulse with high spectral bandwidth. Fig.12D illustrates the final signal output after receive processing of the pulse-echo signals. The alternating amplitude signals are envelope detected. With the embodiment illustrated in Figs.12A, 12B, and 12C the axial spatial resolution if Fig. 12D is equivalent. Improved signal-to-noise with increased transmitted energy is created while preserving high spatial resolution. In some embodiments, the targeted high spectral bandwidth and short duration decoded receive signals may be enabled by the linear, high-power, transmit amplifier 414 and the high bit count DAC, contributing to high dynamic range, high image quality and higher spatial resolution.

[0192] The final image line after signal processing using a decode filter, such as a finite impulse response (FIR) filter, can recombine and reverse the temporal stretching of the transmit signal (Tc), recovering the axial resolution associated with a receive signal from a transmit pulse like Ta, however the energy in the received signal is significantly greater due to the pulse stretching. In some embodiments, higher frequencies may be used to further improve spatial resolution image quality. In some embodiments, the FPGAs and / or the at least one processor of the workstation 118 may use the timing from the Transmit (T) / Receive (R) Event Matrix to selectively combine the processed receive echoes from multiple T / R events in the direction of a desired single line of the image. System Cable

[0193] Fig.13 illustrates a cross-section of a system cable 1200 according to one embodiment. As described above, the IVUS system 100 may include a unique system cable to facilitate a connection between the CIM and the USC / workstation. It is recognized that longer cables increase signal loss, demand higher power, and may not meet electrical requirements for standard communication protocols. Long cables additionally are susceptible to cross- talk between conductors in the cable, and electromagnetic conformance (EMC) susceptibility and emissions. Thus, there is a recognized need for improved IVUS system cabling that allows transmit and receive signals to be transmitted over longer distances to facilitate improved imaging of IVUS systems.

[0194] Embodiments described herein may provide for a system cable, e.g. the system cable 1200, which meets the needs described above. The system cable 1200 may be adaptable to the operating room environment.The system cable 1200 may be mechanically strong so other equipment that may roll over the cable will not damage the cable 1200. The system cable 1200 may meet medical device industry compliance standards. The system cable 1200 may be shielded from noise including environmental noise such as radio stations, lab equipment, and other nearby electronic equipment. In some embodiments, the system cable 1200 may have an outer diameter that supports bending flexibility but is not unwieldy to handle especially when wound and unwound on support structures on mobile carts. For example, the system cable 1200 may have an outer diameter of 10 millimeters (mm) or less. The system cable 1200 may transmit multiplexed transmit and receive signals which may include line specific control data. For example, the system cable 1200 may transmit multiplexed signals between an USC MUX 310 and the CIM MUX 412. The system cable 1200 may also transmit multiplexed rotating motor position sensing and status interrupt messaging. In some embodiments, the system cable 1200 may also transmit other data and control communications.

[0195] The system cable 1200 may be at least 5 meters long. In some embodiments, the system cable 1200 is 6 meters long. The system cable 1200 may have an outer diameter greater than 10 mm. The system cable 1200 may have a plurality of conductors, e.g. a plurality of wires. Conductors may be grouped into shielded twisted pairs (STP) and employ balanced differential low voltage signaling for improved noise immunity and EMC emissions. Each of the plurality of conductors may have one or more of: an associated electromagnetic shielding, jacket thickness, jacket durability, minimal electrical losses, minimal ground voltage offset, acceptable electromagnetic conformance, which can reduce and optimize the number of conductors needed for the application to aid in cable size reduction. In some embodiments, the size of the conductors may be based on the transmitted power. Inappropriately sized conductors can result in power loss and ground offset between the two ends of the cable, potentially creating signal integrity issues for ground referenced signals.

[0196] As shown in Fig.13, the system cable 1200 may include a plurality of 28 American Wire Gauge (AWG), 90 Ohm characteristic impedance, Shielded Twisted Pair (STP) conductors. The plurality of conductors may transmit direct current power, analog transmit and receive signals, and digital synchronization and communications. In some embodiments, the system cable 1200 may also include one (1) double-shielded twisted pair (DSTP) unit (labeled Unit A1). The one DSTP (Unit A1) may balance differential bi-directional analog signals between the workstation / USC and CIM. In some embodiments, the system cable 1200 may also include six (6) 28 AWG STP units (labeled B1 to B6). Each of the twisted pairs B1 to B6 may be used for a specific purpose. STP B1 and STP B2 may deliver power and make a ground connection between USC / workstation and CIM, respectively. STP B3, B4, B5, and B6 may be used for communications and control signaling.

[0197] STP B3 may support multi-level signaling for presence detection of the CIM by the USC / workstation. STP B3 may support bidirectional fault signaling between the CIM and the USC / workstation. Robust presence sense and fault detection of common system cable 1200 faults of short to ground and open on the STP may be indicated as a fault condition. A fault condition can also be generated and sensed at either end by theUSC / workstation or CIM, providing coordinated shutdown of ultrasound imaging and motor control of the rotating imaging core when a system fault is detected on either side.

[0198] STP B4 may transmit real-time ultrasound signal timing and control information from the USC / workstation to the CIM. The timing of a transmit pulse, the transmit pulse duration, and the temporal window required to receive the reflected echo signals from the tissue before the next transmit pulse arrives may be provided on a line-by-line basis. Additionally, STP B4 may support transmission of control information synchronous to each ultrasound line including parameters such as first line of an image frame, transmit pulse type, TGC value, and a receive filter selection. In some embodiments, interleaves functions may be employed to support transmission of both the basic timing control and the control information. For example, the control information may be serially communicated as embedded data while the ultrasound transceiver transmitting. This window during active ultrasound transmission allows the CIM to receive the embedded data for setting up proper controls.

[0199] STP B5 may transmit signals regarding timing event(s), CIM events, and status reporting. Timing events may include the US synch events. As discussed above, the US synch events allow the IVUS system to monitor the motor’s actual location vs. an expected location. The motor home position may be communicated by the CIM to the USC / workstation via STP B5 with low latency (e.g., < 5 microseconds) to coordinate the start of an ultrasound frame. Since this synchronization may take little time relative to the full time to complete an imaging frame, STP B5 can transmit general CIM reporting to the USC / workstation between US synch events. CIM event and status data may include fault status, temperatures, voltages, motor torque values using amperage measurements, and similar monitoring parameters.

[0200] STP B6 may be a dedicated high speed (e.g., >5 Megabits per second (Mbps)) bidirectional data link between the USC / workstation and the CIM. STP B6 may provide general purpose serial communications for configuration, control, status, and programming. As an example, a new FPGA code may be transferred from the USC / workstation to the CIM to update the CIM FPGA. In some embodiments, STP B6 may include error detection and auto-retransmission when an error is detected at the data link layer to reduce burden on the at least one processor of the workstation.

[0201] The system cable 1200 may employ low-voltage differential signaling. A differential pair may include 2 conductors twisted together forming a twisted pair (TP). The system cable 1200 may employ differential signaling standards with high tolerance to common-mode voltage offsets, such as multipoint-LVDS (MLVDS), which may reduce sensitivity to ground offset and enable use of smaller size power conductors in the cable. In some embodiments, shielding may be provided over the individual conductors or pairs of conductors to reduce cross-talk and electromagnetic interference and improve electrical impedance control. The shielding may include a double outer shield with metal foil (“Shield Tape 2”) and metal braid (“Braiding shield 2”) for electromagnetic conformance (EMC) protection, and a durable outer jacket (Sheath) made of a thermoplastic polyurethane of 1.0 mm thickness providing mechanical strength and dielectric strength for safety.

[0202] Artificial Intelligence: In several embodiments, the systems described herein, including for example the advanced intravascular ultrasound platform, leverage AI to enable image interpretation, enhance total- system capabilities, and streamline workflows to maximize the clinical value. In some embodiments, advantageously, physicians will not need to integrate (e.g., cognitively integrate) imaging data spatially and temporally to fully interpret the clinical condition. Instead, systems according to several embodiments described herein can leverage the power of AI with generational advancements to go beyond single image interpretation. In several embodiments, the AI-powered engine, for example, may include a workstation that enhances image interpretation with a simplified workflow improving overall useability. Machine learning is used in several embodiments. In one embodiment, the AI-ready processing power is designed to support real time and on-demand image interpretation. The AI powered workstation can provide high end processing and an AI engine for advanced signal and image processing. In various embodiments, the native image data capture provides for superior image interpretation (e.g., border detection, identification and measurement of vessel size, vessel disease, dissection, plaque morphology, etc.). In several embodiments, the systems described herein provide simplified measurement via automated border detection (e.g., AI algorithms automatically identify borders of a lumen, vessel, tissue, lesion, plaque, etc.). In several embodiments, the system provides simplified measurement via semi-automated border detection (e.g., the user can manually adjust or modify automated AI algorithms that identify borders of a lumen, vessel, tissue, lesion, plaque, etc. with the border selection reconfigured based on user modifications). In one embodiment, AI plaque identification utilizes AI algorithms to automatically classify and identify types of plaque within the imaged area to provide user guidance on treatment options (e.g., using color coding, icons or text overlays can be used to indicate what type of condition, such as plaque, may be present for the selected image). In several embodiments, the data driven platform is designed to collect data, simplify image interpretation, with AI processing power to support real time and on-demand image interpretation and reduce user cognitive load to help (i) identify lumen size, (ii) visualize dissections, (iii) characterize disease morphology, (iv) locate and quantify stenosis, and / or (v) identify true lumen. In some embodiments, image interpretation is used to identify thrombus, thrombosis, clots, embolisms, plaque, calcium, tissue health, stent or balloon apposition, and / or stent or balloon “health” or condition. Image interpretation may involve imaging to evaluate quality and / or position of placement of an existing stent. Image interpretation can involve identifying position relative to lumen walls, determine level of and / or quality of tissue grown into and around the stent or balloon. In one embodiment, for example with a bioresorbable stent, image interpretation can involve (i) evaluating the amount of dissolving of the stent, (ii) determining if the dissolving of the stent is in accordance with expected decay patterns (e.g., determining whether the level of decay on one side of the stent similar to the other side of the stent, and if not, that may indicate a problem with stent placement, or if the stent is dissolving more rapidly than expected that could indicate the stent will not provide the tissue with the expected structural support). High-fidelity ultrasound data is used in one embodiment to drive improved image generation and image interpretation, with the option for leveraging artificial intelligence and / or machine learning. In various embodiments, catheters, devices, systems, and methods may be configured for use in performing edge-basedmachine learning computations associated with an image or image analysis using an artificial intelligence algorithm to identify a tissue border, plaque, calcium, thrombus, dissection, and / or stent apposition. In some embodiments, data, algorithms, AI and / or ML are used to obtain data from one or more sensors and provide feedback on operational aspects (such as imaging parameters) through a feedback loop (e.g., closed feedback loop / automated) or through user directed adjustments. In some embodiments, data, algorithms, AI and / or ML are used to obtain data from one or more images and provide feedback on operational aspects (such as imaging parameters and / or therapy) through a feedback loop (e.g., closed feedback loop / automated) or through user directed adjustments.

[0203] In several embodiments, the systems described herein, including for example the advanced intravascular ultrasound platform, leverage artificial intelligence (AI) to enable image interpretation, enhance total- system capabilities, and streamline workflows to maximize the clinical value. In some embodiments, advantageously, physicians will not need to cognitively integrate imaging data spatially and temporally to fully interpret the clinical condition. Instead, systems according to several embodiments described herein can leverage the power of AI with generational advancements to go beyond single image interpretation. The AI-powered engine, for example, enhances image interpretation with a simplified workflow improving overall useability. Machine learning is used in several embodiments. In one embodiment, the AI-ready processing power is designed to support real time and on-demand image interpretation (e.g., so as to improve performance of automated or semi-automated assessment, classification, diagnosis and / or therapy by increasing the speed at which information is provided, increasing the quality or accuracy of the information (e.g., imaging data and / or measurement data), increasing the amount of information (e.g., additional images or information that could not previously be determined by previous systems), and / or by increasing a level of confidence in the diagnosis and / or therapy determined by one or more clinicians). The AI powered workstation can provide high end processing and an AI engine for advanced signal and image processing. In various embodiments, the native image data capture provides for superior image interpretation (e.g., border detection, identification and measurement of vessel size, vessel disease, dissection, plaque morphology, etc.). In several embodiments, the systems described herein provide simplified measurement via automated border detection (e.g., AI algorithms automatically identify borders of a lumen, vessel, tissue, lesion, plaque, implant, stent, balloon, etc.). In several embodiments, the system provides simplified measurement via semi-automated border detection (e.g., the user can manually adjust or modify automated AI algorithms that identify borders of a lumen, vessel, tissue, lesion, plaque, implant, stent, balloon, etc. with the border selection reconfigured based on user modifications). In one embodiment, AI plaque identification utilizes AI algorithms to automatically classify and identify types of plaque within the imaged area to provide user guidance on treatment options (e.g., using color coding, icons or text overlays can be used to indicate what type of condition, such as an irregularity such as plaque, may be present for the selected image). In several embodiments, the data driven platform is designed to collect data, simplify image interpretation, with AI processing power to support real time and on-demand image interpretation and increase ease of use and reduce user cognitive load to help (i) identify lumen size, (ii) visualize dissections, (iii) characterize disease morphology, (iv) locateand quantify stenosis, and / or (v) identify true lumen. In some embodiments, image interpretation is used to identify thrombus, plaque, calcium, tissue health, stent or balloon apposition, and / or stent or balloon “health” or condition. Image interpretation may involve imaging to evaluate quality and / or position of placement of existing stent. Image interpretation can involve identifying position relative to lumen walls, determine level of and / or quality of tissue grown into and around the stent or balloon. In one embodiment, for example with a bioresorbable stent, image interpretation can involve (i) evaluating the amount of dissolving of the stent, (ii) determining if the dissolving of the stent is in accordance with expected decay patterns (e.g., determining whether the level of decay on one side of the stent similar to the other side of the stent, and if not, that may indicate a problem with stent placement, or if the stent is dissolving more rapidly than expected that could indicate the stent will not provide the tissue with the expected structural support). In several embodiments, AI / ML models (e.g., algorithms, neural networks) are used in real time to provide real-time feedback (e.g., the evaluations and / or determinations described above and / or predictive outcomes using trained AI / ML models based on prior annotated images, while the operator or user is viewing the images in a diagnostic and / or therapeutic procedure). In several embodiments, the systems and methods disclosed herein may or may not be used in conjunction with recording data and using AI / ML models and techniques in retrospect for automated or semi- automated analysis of images after the imaging takes place. In some embodiments, AI / ML models and techniques may be used in real time and / or in retrospect, either alone or in combination. In several embodiments, AI / ML models and techniques are used whether in real time or alone, whether in real time and based on recordings, and / or whether based on recordings alone to identify various characteristics, including but not limited to, the size of the lumen, the presence of calcium, the grade of calcium, obstructions, lesions, deformities, placement of stents, occluders (e.g., coils) and other devices, etc. In some embodiments, AI / ML models and techniques are used to aid to the physician in making a diagnosis (e.g., by providing predictive outcomes or treatment recommendations using trained AI / ML models based on prior annotated images).

[0204] Several embodiments may be configured to identify the borders, boundaries, or edges of abnormalities such as tumors, lesions, plaque, etc. Such abnormalities may be vascular and within a vessel or located outside a vessel. During surgery, ablation or other intervention, it can be difficult to tell where an abnormality ends and healthy tissue begin. Thus, unnecessary multiple procedures may be required, which can lead to poorer outcomes such as increased cost and strain on the medical system, increased pain, and longer hospital stays. Many surgeries would be improved with better tissue visualization using the technology described herein. By determining the edge (e.g., border) of tumors or other undesired target region, not only can healthy tissue be preserved but the likelihood is increased that complete removal or at least more of the undesired tissue / region is removed. Several embodiments allow medical professionals to clearly visualize tissue borders, blood vessels, nerves, lymph ducts, etc. in real time during surgery or other procedure, and additionally allow for post-procedure enhanced images. In some aspects, the imaging device can be placed in a vessel but is also able to visualize tissue (including abnormalities) outside the vessel. The enhanced images provided by various embodiments described herein (e.g., real time availability of enhancedimages) allow precision surgical intervention that reduces the risk of error and additional corrective surgeries. Improved patient outcomes, including complete removal of cancerous tissue, lesions, plaque, etc. while preserving healthy tissue, is accomplished by the enhanced visualization described in several embodiments described herein. Further, visualization of vessels or tissues outside of vessels may be performed without dyes or radiation in many embodiments. Using AI, machine learning and / or data analysis, additional embodiments described herein can be further used to more accurately identify the distinction between healthy tissue and diseased tissue. Also, such tools may be able to predict whether a certain margin of tissue - which seems healthy at the time but is actually high risk to contain unhealthy cells for example - should be removed, which in turn reduces the likelihood that further surgeries are required.

[0205] Smaller vessel sizes can pose difficulties in placement and positioning of stents (and other devices or interventional therapies), and several embodiments described herein are adapted to image smaller vessels and facilitate placement and positioning of stents and other devices (occluders, etc.), and facilitate or otherwise inform therapy (such as mechanical clot retrieval, aspiration, lithotripsy, angioplasty, bypass procedures, etc.). Using AI, machine learning and / or data analysis, additional embodiments described herein can be further used to correlate a patient’s risk based on the enhanced images, and can further suggest that a particular therapy may be more effective to treat such conditions (or suggest that the patient should be scheduled for follow up because the patient has an increased risk).

[0206] AI may be used in real time in conjunction with imaging. This has several advantages in some embodiments, for example, real-time AI can be employed for data collection, predictive outcomes and / or correlations. In one embodiment, AI is used for predictive outcomes, e.g., determining co-morbidity in a given percent of cases where hard plaque is identified in a particular artery, such as in the femoral artery. In several embodiments, real time AI is accomplished by measuring and providing feedback identifying tissue borders and / or edges. In some embodiments, imaging as described herein is used to identify and / or guide the placement of an occluder in a peripheral vessel or in coronary (or other) tissue.

[0207] In one embodiment, the system can measure thickness and circumference and grades of calcium, which can dictate therapy. In several embodiments, blood flow (e.g., speckle visualization) is visualized with the system allowing identification of thrombus existence and thrombus parameters. In one embodiment, blood dynamics and / or speckle visualization may be displayed in adjacent frames. In several embodiments, visualization of a vein is possible when the catheter is in an artery and / or visualization of an artery is possible when the catheter is in a vein. In several embodiments, visualization in collateral tissue and vessels is possible while the catheter is in a different vessel. In several embodiments, IVUS clarity of imaging visualization is comparable to an external ultrasound or CT. In several embodiments, visualization in collateral tissue and vessels is achieved while the catheter is in a different vessel. For example, although the catheter is placed in a first vessel (the “interrogated vessel”), the enhanced imaging provided herein is capable of visualizing one or more non-interrogated vessels and structures. This is particularly advantageous in some embodiments because the procedure can be performed more quickly (becausemultiple vessels do not have to be individually accessed) and because visualization of vessels and structures can be obtained in situations where catheter access may be difficult (small, tortuous, etc.) or undesired (e.g., unstable clots or vessel injury, etc.).

[0208] In several embodiments, artificial intelligence and / or machine learning (AI / ML) are employed to enable and / or enhance measurements and / or image interpretation using the technologies described herein. In one embodiment, the system is matched for high definition (e.g., HD, UHD, HD+, etc.) image quality using acoustics and signal processing customized for peripheral vascular imaging with enhanced resolution and / or penetration. Several embodiments are configured for intravascular imaging with a platform that is optimized for peripheral and / or coronary vascular procedures that will enable improved image interpretation, intervention guidance, and enhance ease of use and improve overall usability to streamline intraprocedural and clinical workflow In several embodiments, the system improves usability with a contemporary system featuring a simplified user-interface and enhanced total-system capabilities leveraging AI to streamline workflow and image interpretation. In several embodiments, the systems described herein, including for example the advanced intravascular ultrasound platform, leverage AI to enable image interpretation, enhance total-system capabilities, and streamline workflows to maximize the clinical value. In some embodiments, advantageously, physicians will not need to integrate (e.g., cognitively integrate) imaging data spatially and temporally to fully interpret the clinical condition. Instead, systems according to several embodiments described herein can leverage the power of AI with generational advancements to go beyond single image interpretation. In several embodiments, the AI-powered engine, for example, may include a workstation that enhances image interpretation with a simplified workflow improving overall useability. Machine learning is used in several embodiments. In one embodiment, the AI-ready processing power is designed to support real time and on-demand image interpretation. The AI powered workstation can provide high end processing and an AI engine for advanced signal and image processing. In various embodiments, the native image data capture provides for superior image interpretation (e.g., border detection, identification and measurement of vessel size, vessel disease, dissection, plaque morphology, etc.). In several embodiments, the systems described herein provide simplified measurement via automated border detection (e.g., AI algorithms automatically identify borders of a lumen, vessel, tissue, lesion, plaque, etc.). In several embodiments, the system provides simplified measurement via semi-automated border detection (e.g., the user can manually adjust or modify automated AI / ML algorithms that identify borders of a lumen, vessel, tissue, lesion, plaque, etc. with the border selection reconfigured based on user modifications). In one embodiment, AI plaque identification utilizes AI algorithms to automatically classify and identify types of plaque within the imaged area to provide user guidance on treatment options (e.g., using color coding, icons or text overlays can be used to indicate what type of condition, such as plaque, may be present for the selected image). In several embodiments, the data driven platform is designed to collect data, simplify image interpretation, with AI processing power to support real time and on-demand image interpretation and reduce user cognitive load to help (i) identify lumen size, (ii) visualize dissections, (iii) characterize disease morphology, (iv) locate and quantify stenosis, and / or (v) identify true lumen. In someembodiments, image interpretation is used to identify thrombus, thrombosis, clots, embolisms, plaque, calcium, tissue health, stent or balloon apposition, and / or stent or balloon “health” or condition. Image interpretation may involve imaging to evaluate quality and / or position of placement of an existing stent. Image interpretation can involve identifying position relative to lumen walls, determine level of and / or quality of tissue grown into and around the stent or balloon. In one embodiment, for example with a bioresorbable stent, image interpretation can involve (i) evaluating the amount of dissolving of the stent, (ii) determining if the dissolving of the stent is in accordance with expected decay patterns (e.g., determining whether the level of decay on one side of the stent similar to the other side of the stent, and if not, that may indicate a problem with stent placement, or if the stent is dissolving more rapidly than expected that could indicate the stent will not provide the tissue with the expected structural support). High-fidelity ultrasound data is used in one embodiment to drive improved image generation and image interpretation, with the option for leveraging artificial intelligence and / or machine learning. In various embodiments, catheters, devices, systems, and methods may be configured for use in performing edge-based machine learning computations associated with an image and / or image analysis using an artificial intelligence algorithm to identify one or more of a tissue border, plaque, calcium, thrombus, dissection, and / or stent apposition.

[0209] Artificial intelligence and / or machine learning (AI / ML) are employed in some embodiments to enable and / or enhance measurements and / or image interpretation (e.g., through improved or enhanced images, additional information, and / or more confidence indicators that provide increased confidence in the information or data provided) using the technologies described herein. In one embodiment, the system generates high definition (e.g., HD, UHD, HD+, etc.) image quality using acoustics and signal processing customized for peripheral vascular imaging with enhanced resolution and / or penetration. For example, in accordance with several embodiments, the increased depth of penetration and the enhanced increased spatial and contrast resolution of the imaging obtained by the devices, systems and methods described herein provide an increased amount of usable data of higher quality or information that can be utilized by AI / ML techniques and methodologies, such as those described herein. In several embodiments, the AI / ML techniques and algorithms (either alone or in conjunction with the multi-channel pipeline data processing architecture and / or catheter features described herein), provide improves performance of automated or semi- automated assessment, classification, diagnosis and / or therapy by increasing the speed at which information is provided, increasing the quality or accuracy of the information (e.g., imaging data and / or measurement data), increasing the amount of information (e.g., additional images or information that could not previously be determined by previous systems), and / or by increasing a level of confidence in the diagnosis and / or therapy determined by one or more clinicians). Several embodiments are configured for imaging (such as intravascular imaging and imaging other lumens, tissue and abnormalities) with a platform that is optimized for peripheral and / or coronary vascular procedures that will enable improved image interpretation, intervention guidance, and enhance ease of use and improve overall usability to streamline intra-procedural and clinical workflow. Although intravascular imaging is described herein, several AI / ML embodiments described herein are also used advantageously outside a blood vessel, e.g., for otherlumens or other tissue, such as tumors and abnormalities. In several embodiments, the system improves usability with a contemporary system featuring a simplified user-interface and enhanced capabilities leveraging AI to streamline workflow and image interpretation. For example, the system may incorporate multi-channel parallel processing to facilitate automated or semi-automated application of AI / ML detection, annotation, and assessment (e.g., qualitative or quantitative assessment) of one or more frames of intravascular ultrasound images of a vessel in real time while a clinician is viewing a single frame and before transition to the next image frame in a sequence of image frames. In some embodiments, the AI / ML algorithm processing based on trained models or neural networks may occur in less than 10 ms (e.g., 8 ms, 6 ms, 4 ms, 2 ms) using parallel channels while the image display generation channel may take a substantially longer amount of time (e.g., 30 ms) such that the AI / ML processing occurs in real time, or at a speed greater than the image data display rate. The multiple channel AI / ML parallel processing may be occurring “behind the scenes” and not displayed to the clinician. As one example, a clinician may perform a catheter pullback or advancement routine along a portion of a vessel to capture multiple image frames along the portion of the vessel and the system may store the image frames and perform automated detection, annotation, and metric analysis (e.g., qualitative or quantitative assessment) by application of trained AI / ML models, databases or networks. The detection, annotation, and metric analysis (e.g., qualitative or quantitative assessment) may be catalogued and stored. The clinician can view the detection, annotation, and metric analysis (e.g., qualitative or quantitative assessment) in real time or the information and data can be played back or displayed at a later time. For example, dissections may be identified and / or graded by the system in real time and then identified to the clinician at a later time. The parallel AI / ML processing using multiple different channels may advantageously facilitate AI / ML model assessment (e.g., detection, quantitative calculations) and / or training based on different types of data (e.g., non-human-readable imaging data, such as phase and / or amplitude ultrasound signal information, to detect or assess a certain feature or parameter that correlates to something that is in a human readable image). For example, a data processing pipeline and / or processed data channel may include data that is enhanced or saturated to emphasize a certain feature (e.g., by filtering out high- frequency content or other content not related to a desired detection or metric calculation of the certain feature and / or adjusting intensity or brightness or contrast thresholds). In some embodiments, the enhancements or saturations comprise application of non-linear image enhancement filters to facilitate application of AI / ML algorithms. In some embodiments, the enhancements or saturations preserve edge-based detection.

[0210] In several embodiments, the systems described herein, including for example the advanced intravascular ultrasound platform, leverage Artificial Intelligence (AI) to enable image interpretation, enhance system capabilities, and streamline workflows to maximize the clinical value. For example, the system and integrated platform may allow for seamless updates to AI / ML algorithms as new parameters are identified and trained and / or as new AI / ML techniques are developed. The seamless updates may be the result of unsupervised learning or supervised learning. The training data or data sets and / or AI / ML algorithms may be stored on one or more remote cloud computing servers or databases and updates may be provided to local user systems or workstations over a communications network. Theuse of the cloud storage architecture may also advantageously facilitate ongoing iterative training and validation of the AI / ML models based on ultrasound (e.g., IVUS) images acquired over time (e.g., training and validation for a certain feature, including features not previously trained on that are newly identified). For example, the cloud storage architecture may comprise an electronic architecture that enables storage of data and electronic files on one or more remote storage systems or devices of a cloud computing provider (e.g., Amazon Web Services (AWS)) that are accessible through the Internet or a dedicated private network connection. In some embodiments, the cloud storage architecture advantageously provides security, agility, scalability and reliability while allowing access and communication in real time from anywhere that has a wireless network connection or other connection to the remote storage device(s) or system(s).

[0211] In accordance with several embodiments, supervised learning may include inputting user- adjusted results of an automated result back into the training model(s) in order to improve the training of the AI / ML model(s). For example, if a lumen border is adjusted by a user because the automated result generated by the AI / ML algorithm(s) was not accurate, the adjustment (e.g., manually-adjusted result compared to the automated result) may be provided to the AI / ML model(s) to improve training through supervised learning. The data associated with the manual adjustment can advantageously be uploaded and used to update the AI / ML model(s) so that others can benefit from the improved training set and resulting model prediction performance improvements in the future (e.g., through periodic system updates provided to local workstations over the wireless communications network). In addition, locally- supervised learning may occur at the local workstation “on-the-fly” in real time. For example, the manual adjustments provided by the user at the local workstation may be provided to the AI / ML model in real time and used to train and improve the AI / ML model (and improve the automated results) at the local workstation while the current diagnostics are occurring.

[0212] In some embodiments, advantageously, physicians will not need to integrate (e.g., cognitively integrate) imaging data spatially and temporally to fully interpret the clinical condition. Instead, systems according to several embodiments described herein can leverage the power of AI with generational advancements to go beyond single image interpretation. For example, the techniques described herein can advantageously facilitate dynamic vessel sizing (e.g., venous sizing or arterial sizing) based on an assessment of multiple image frames over time and / or over different anatomical position changes (e.g., position changes caused by respiratory movement or limb movement). In several embodiments, the AI-powered engine, for example, may include a workstation (e.g., workstation 118) that enhances image interpretation with a simplified workflow improving overall usability. Machine learning is used in several embodiments. In one embodiment, the AI-ready processing power is designed to support real time and on-demand image interpretation. The AI powered workstation can provide high end processing and an AI engine for advanced signal and image processing. In various embodiments, the native image data capture (e.g., increased depth of penetration and improved spatial and contrast resolution) provides for superior image interpretation (e.g., border detection, identification and measurement of vessel size, vessel disease, dissection, plaque morphology, etc.). Inseveral embodiments, the systems described herein provide simplified measurement via automated border detection (e.g., AI algorithms automatically identify borders of a lumen, vessel, tissue, lesion, plaque, etc.). In several embodiments, the system provides simplified measurement via semi-automated border detection (e.g., the user can manually adjust or modify automated AI algorithms that identify borders of a lumen, vessel, tissue, lesion, plaque, etc. with the border selection reconfigured based on user modifications). In one embodiment, AI plaque identification utilizes AI algorithms to automatically classify and identify types of plaque within the imaged area to provide user guidance on treatment options (e.g., using color coding, icons or text overlays can be used to indicate what type of condition, such as plaque, may be present for the selected image). In several embodiments, the data driven platform is designed to collect data and simplify image interpretation using AI processing power to support real time and on-demand image interpretation. In several embodiments, this in turn increases the speed and / or accuracy in one or several of the following: (i) identify lumen size, (ii) visualize dissections, (iii) characterize disease morphology, (iv) locate and quantify stenosis, and / or (v) identify true lumen. Additionally, the data driven platform to collect data and simplify image interpretation using AI processing power to support real time and on-demand image interpretation may reduce cognitive load of a user, thus, for example, enhancing ease of use, reducing procedure time, and / or reducing user error.

[0213] In some embodiments, image interpretation is used to identify blood, thrombus, thrombosis, clots, embolisms, plaque, calcium, tissue health, stent or balloon apposition, and / or stent or balloon “health” or condition. Image interpretation may involve imaging to evaluate quality and / or position of placement of an existing stent. Image interpretation can involve identifying position relative to lumen walls, determine level of and / or quality of tissue grown into and around the stent or balloon. In one embodiment, for example with a bioresorbable stent, image interpretation can involve (i) evaluating the amount of dissolving of the stent, (ii) determining if the dissolving of the stent is in accordance with expected decay patterns (e.g., determining whether the level of decay on one side of the stent similar to the other side of the stent, and if not, that may indicate a problem with stent placement, or if the stent is dissolving more rapidly than expected that could indicate the stent will not provide the tissue with the expected structural support).

[0214] Data collection as described herein (e.g., high-fidelity ultrasound data) is used in one embodiment to drive improved image generation and image interpretation, with the option for leveraging artificial intelligence and / or machine learning. In various embodiments, catheters, devices, systems, and methods may be configured for use in performing edge-detection machine learning computations associated with an image and / or image analysis using one or more artificial intelligence algorithms to identify one or more of a blood, tissue border, plaque, calcium, thrombus, dissection, and / or stent apposition. Edge detection algorithms may include gradient-based algorithms (e.g., Sobel operator, Roberts Cross operator, Prewitt operator), second-order derivative algorithms (Laplacian-based algorithms), Canny Edge detection algorithms, and / or wavelet transform algorithms. Convolutional neural networks (e.g., U-Net fully convolutional neural networks with or without skip layer connections), structured forests or other deep-learning or machine learning algorithms may also be used to perform edge detection.

[0215] In various embodiments, the ultrasound device (e.g., IVUS catheter) is configured for imaging (alone or in combination with therapy) tissue and / or plaque (e.g., any one or more of hard plaque, soft plaque, vulnerable plaque, calcified plaque, substantially non calcified plaque). In various embodiments, the ultrasound device (e.g., IVUS catheter) is configured for imaging thrombus. In several embodiments, the technologies described herein are used for one or more of the following: identification of blood, thrombus, dissection detection and / or grading, calcium severity, vessel measurement, and / or preprocedural and postprocedural planning. In several embodiments, the technologies described herein are used to guide the sizing of stents, identify stent placement, apposition and / or expansion, assess lesion morphology, vascular wall thickening, loss of luminal patency, and / or vascular insufficiency, quantify plaque burden, identify complications from procedures (e.g., vessel dissections), and / or evaluate stent failure with stent thrombosis or in-stent restenosis. The technologies described herein can distinguish between blood, lipids, calcified plaque, and tissue proliferation. In many embodiments, better imaging detail is provided than, for example, angiography.

[0216] In accordance with several embodiments, AI / ML techniques described herein that are facilitated by the enhanced imaging described herein may be used to provide improvements or enhancements to any of the following: diagnostic information (e.g., vessel boundary detection and identification; blood flow detection or information; blood speckle information, tissue characterization or detection, identification of stenosis, thrombus, lesion, dissection, calcium or plaque; stent or balloon detection or identification; guidewire detection and cancellation from a displayed image (e.g., by hiding of noise artifact or performing image subtraction or pixel subtraction techniques such that the guidewire is removed from the displayed image); collateral vessel identification and measurements, such as branches of the vessel or adjacent and / or nearby vessels); qualitative or quantitative metrics or assessments associated with the images or diagnostic information (e.g., lengths, sizes, areas, volumes, scores, grading, confidence measures or values, classification, severity analysis, hemodynamic values); treatment or other intervention recommendations (which may be dictated or guided, for example, by the diagnostic information and / or qualitative or quantitative metrics or assessments above); post-intervention vessel assessment (e.g., dissection detection / grading, true lumen detection, stent detection or stent apposition evaluation); and / or prediction of outcomes or co-morbidities (e.g., prediction of patient eligibility for a particular diagnostic or therapeutic intervention or for further diagnostic or therapeutic intervention, prediction that a patient will need further intervention in a certain amount of time in the future, a prediction that a particular intervention will not provide a desired outcome so as to reduce likelihood that a patient receives unnecessary treatment, or a prediction that the patient likely has a condition warranting intervention in a second vessel or for a different indication based on an assessment or metric in a first vessel). In accordance with several embodiments, the AI / ML techniques described herein facilitate increased confidence and speed in determination of treatment of the vessel. The prediction of outcomes may also be based on integration and assessment of non-IVUS data (such as but not limited to, CT imaging data, MRI imaging data, angiography imaging data, fluoroscopic data, external ultrasound data, Doppler ultrasound data, X-ray imaging data, fractional flow reserve (FFR) data, coronaryflow reserve (CFR) data, instantaneous wave-free ratio (IFR) data, computational fluid dynamics data, flow measurement data, microvascular resistance data, pressure data, or other physiologic data received from sensors integrated with the catheters and systems described herein or from separate devices and systems. In some embodiments, the different data may be co-registered with the IVUS imaging data such that the other data is associated with corresponding portions of the imaged vessel. The co-registration may advantageously facilitate analysis and treatment or diagnostic recommendations.

[0217] For example, in some embodiments, blood flow data indicating that blood flow is lower than expected may be combined with IVUS data to predict (using AI / ML techniques) a percentage or time-based likelihood of a heart attack or stroke or peripheral artery disease. In some embodiments, both IVUS data and extravascular ultrasound data may be combined and processed using AI / ML techniques to assess progress and completion of an aneurysm treatment (e.g., coil embolization). In some embodiments, IVUS imaging data may be combined with FFR, CFR or iFR data to perform treatment simulation and / or to predict treatment outcomes and / or to generate automated treatment recommendations (e.g., stent size, location, etc. to enhance revascularization and increase blood flow). In some embodiments, IVUS imaging data may be combined with angiographic imaging data to identify branched vessels that may provide alternative flow paths such that placement of a stent at a particular stenosis location may not be necessary. The predictions and / or treatment recommendations generated by the AI / ML techniques described herein may advantageously improve patient care by eliminating unnecessary or less-effective interventions, by reducing the time to intervention, and / or by increasing confidence by the clinicians in making decisions regarding diagnoses and / or intervention.

[0218] In some embodiments, the ultrasound technology as described herein provides information (or images that can be used to determine more accurate and more helpful and / or more overall metrics) on the circumference, grade, and / or thickness of calcium deposits in a vessel such as an artery or vein, or other tissue. This information, which may be based on enhanced imaging capabilities described herein, is then used to, for example, facilitate improved therapy based on additional and / or improved metrics and visualization of additional structural and / or functional features (e.g., collateral vessels or other tissue, blood flow, branches, etc.). The improved therapy may include not performing certain intervention or diagnostics based on the additional and / or enhanced information, thereby reducing cost and unnecessary intervention and potentially increasing safety and efficacy and patient satisfaction. The improved therapy may include improved treatment recommendations generated by AI / ML models based on the additional and / or enhanced information. The improved therapy may include more accurate sizing and positioning of a stent (which may be automated using the AI / ML models) based on the additional and / or enhanced information (e.g., based on an increased ability to visualize individual struts of a stent and the apposition of the struts against the wall of the vessel.

[0219] The enhanced visualization of collateral vessels may advantageously be used to facilitate enhanced automated treatment recommendations provided by the AI / ML models, as a result of the additionalinformation or data provided by the improved image quality of the ultrasound (e.g., IVUS) images. For example, the additional information or data provided by the collateral vessels may help guide the type or size of stent based on the location of side branches off of the vessel of interest. In other words, visualizing side branches may assist in more precise stent selection and placement. Collateral vessels provide useful landmarks and may be implicated in vessel compression, thereby resulting in diminished blood flow. The enhanced image quality provided by the ultrasound imaging described herein (e.g., enhanced depth of penetration and resolution) may advantageously facilitate using AI / ML techniques to generate a 3D vessel map of a lumen of interest, side branch locations, and surrounding collateral vessels. Methods described herein may include performing the recommended treatment or intervention (e.g., insertion of a stent having a particular size at a particular location).

[0220] In accordance with several embodiments, AI / ML techniques may be used for one or more of the following general categories: (1) vessel anatomic assessment, (2) tissue type detection, classification or morphology, (3) post-intervention vessel assessment, and / or (4) image enhancement.

[0221] Vessel anatomic assessment may include, for example, vessel size assessment (e.g., cross- sectional dimensions), automated healthy reference vessel detection (e.g., the vessel without any stenosis, calcium, plaque, lesion, thrombus or other abnormality), lesion length, actual lumen size or boundary determination (e.g., the vessel with any stenosis, calcium, plaque, lesion, thrombus or other abnormality), dynamic vessel sizing in two dimensions or three dimensions (e.g., sizing based on monitoring the vessel over time or during anatomical position changes, such as position changes due to limb movement or respiratory movement), blood detection, and / or flow or speckle evaluation or assessment.

[0222] Tissue type detection, classification or morphology may include, for example, plaque morphology or classification or burden assessment (e.g., qualitative or quantitative scoring or grading), calcium identification or detection or burden assessment (e.g., qualitative or quantitative thickness or circumference calculations, scoring or grading), and / or thrombus detection or burden assessment (e.g., qualitative or quantitative scoring or grading, such as FFR values).

[0223] Post-intervention vessel assessment may include, for example, dissection detection and / or grading, true lumen detection, and / or stent detection / apposition evaluation. For example, the enhanced imaging described herein may facilitate improved imaging of individual struts of the stent to facilitate assessment of vessel wall apposition.

[0224] Image enhancement may include, for example, spatial resolution and / or contrast image enhancement to improve image quality. The image enhancement may include a nonlinear image enhancement (NLIE) function that can preserve edges and facilitate edge detection enhancements that make it easier for an AI / ML algorithm to find features of interest.

[0225] The ability to process and analyze multiple high-quality image frames as described herein may advantageously facilitate dynamic assessment over time (either 2D assessment or 3D assessment). For example, theenhanced quality images may show pulsing of an artery over time that may be detected or assessed based on vessel wall motion. Diminished wall motion may, for example, be an indicator of a particular disease state or condition. For example, diminished or reduced wall motion may be a result of harder or stiffer arteries, which may be an indicator of calcification or plaque buildup. The dynamic vessel assessment over time facilitates the wall motion assessment that would not be possible without dynamic vessel assessment. Cardiac cycle information or data may be extracted from the wall motion. In various implementations, the dynamic assessment may be provided using 3D images or model display or via 2D information, such as a 2D chart or graph over time.

[0226] In accordance with several embodiments, the systems and methods and architectures described herein may facilitate storing and use of phase data associated with the ultrasound (e.g., IVUS) images (in addition to magnitude and / or amplitude data) that is not currently stored or used by existing IVUS systems (which do not have the processing electronic architecture, the processing power, or storage capabilities to store the phase data). Ultrasound signals include both amplitude and phase during transmission and reception of acoustic pulses. During processing of ultrasound pulses to generate an image, the phase is conventionally removed to leave only the magnitude of the signals as the varying magnitude drives varying unipolar greyscale intensities on a display. Full and complete ultrasound data includes both amplitude and phase, and removing the phase during processing removes useful information. Processing of both amplitude and phase as inputs to AI / ML algorithms increases the ability to improve detection and classification of tissue. The phase data may advantageously be used to facilitate phase-based AI / ML techniques and calculations that may improve detection and / or assessment of various parameters or conditions and / or improve treatment options or recommendations or other capabilities not possible without phase data. For example, variations in phase may provide a strong indicator or signature for a particular condition, parameter, or outcome. In some embodiments, phase data may be used to improve characterization of tissue types or classification of tissue (e.g., tissue that has blood or whether the tissue is a thrombus or blood or soft plaque or hard plaque) or to improve detection of blood flow or blood speckle. In accordance with several embodiments, the amplitude and phase across the frequency spectra of the ultrasound signals can improve the detectability of different tissue types compared to detection with amplitude or magnitude alone.

[0227] In accordance with several embodiments, the systems and methods and architectures described herein may facilitate storing and use of amplitude data associated with the IVUS images that is not currently stored or used by existing IVUS systems (which do not have the processing power or storage capabilities to store the amplitude data). Amplitude and phase data, with or without magnitude data, may be used in combination for AI / ML detection and assessment as well.

[0228] In various embodiments, the AI / ML algorithm processing may be trained to the specific system. In accordance with several embodiments, the systems and electronic architectures described herein may advantageously train the AI / ML models in a robust manner using a disparate-source training approach that incorporates a diverse set of input data (e.g., IVUS imaging data) from multiple sources (e.g., various systems, various libraries ordatabases with images having variation in image resolution and depth of penetration) such that when new imaging data is applied to the AI / ML models, the output is substantially improved compared to AI / ML models trained on a more limited set of input data. For example, the disparate-source training approach may include a diverse set of input data that includes input images of multiple different vessels (e.g., coronary vessels, peripheral vessels, veins, arteries, different portions or sections of the aorta, brain vessels, etc.), input images obtained from multiple different types of imaging catheters (e.g., IVUS catheters operating at multiple different frequencies (e.g., frequencies in a range of 10 – 90 MHz (e.g., 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 and 90 MHz and values and ranges therein)), catheters provided by different manufacturers, and / or catheters operating on different principles of operation, such as rotational transducer catheters incorporating a single rotating transducer versus phased array catheters incorporating multiple stationary transducers), input images obtained by multiple clinicians at multiple different locations at multiple different times on multiple different patients).

[0229] In some embodiments, use of a disparate-source training approach involving images of multiple different types of vessels, involving images including multiple different disease states, involving images obtained from multiple different patients, and / or involving images obtained by the same or different imaging catheters (e.g., catheters provided by different manufacturers) at different imaging frequencies provides a more robust thrombus, plaque or calcium detection and assessment, as well as identification of irregularities. In accordance with several embodiments, the diversity of the input image data under the disparate-source approach for initial training of the AI / ML model allows for a reduced overall number of input images that are required to be used for training while still providing sufficient quality (e.g., a lumen dice score above 0.8).

[0230] In various embodiments, the input images comprise cross-sectional IVUS images of the vessel sampled along the vessel. However, the input images may comprise any suitable images of the vessel and are not limited to cross-sectional images of the vessel. As discussed previously, the input images may include non-human- readable image data or data that would not be visually pleasing to a user (e.g., enhanced or saturated images via application of non-linear image enhancement filters or intensity adjustments). The input to the AI / ML model(s) may include frame-based input or video-based input. Video-based input may allow the AI / ML model(s) to take advantage of temporal cues.

[0231] In accordance with several embodiments, the AI / ML models described herein may comprise a segmentation model or edge-detection approach designed to identify and label various portions (e.g., borders, edges, tissue types) of an IVUS image. The AI / ML models may include a single model or multiple separate models that run in parallel or in sequence. The AI / ML modes may also be trained or run in a nested fashion wherein the results of one model contribute to input to another model. For example, a first AI / ML model may be used to identify a true lumen of a vessel or portion of a vessel (e.g., a true lumen having a high confidence measure). The output of this first AI / ML model may be input to another AI / ML model for performing detection, identification, or qualitative or quantitative assessment based on the true lumen (e.g., plaque classification, thrombus detection, dissection detection or grading, stenosisquantification, stent apposition assessment, other tissue type detection, etc.). In another example, a first AI / ML model may be used to identify a medial wall or border of a lumen (such as a vessel) and then that output may be used as the input for a second nested model to classify tissue, abnormalities, or structure in between the media and the intima of the vessel wall. In several embodiments, imaging methods may include one or more of the following: (i) identification of types of tissue or abnormalities that are selected from the group consisting of: intima, media, adventitia, lumen, plaque, and calcium, (ii) generating an output for display on a graphical user interface that indicates the different types of tissue, (iii) different types of tissue are displayed in different colors, (iv) generating a confidence measure associated with the classifying, (v) outputting the confidence measure on a display of a graphical user interface, (vi) confidence measure is a global confidence measure or a local confidence measure, and / or (vii) the geometric features include a cross-sectional measurement, a thickness, and / or a length.

[0232] In accordance with several embodiments, a number of AI / ML image interpretation algorithms may be active when stationary with respect to the patient’s tissue or active during a “pullback recording” (as described elsewhere herein) and may detect vascular features (e.g., true lumen, intima-media borders, adventitia, collateral vessels or s...

Claims

WHAT IS CLAIMED IS:

1. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body; an imaging core disposed in the catheter body, the imaging core comprising a transducer; an imaging core cable configured to rotate the transducer; a workstation comprising: a controller configured to: generate two or more digital transmit signals at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits, the two or more digital transmit signals comprising at least a first transmit waveform and a second transmit waveform, wherein the first transmit waveform is longer than the second transmit waveform, wherein at least one of the first transmit waveform and the second transmit waveform comprises coded phases that are nonlinear with time; receive a plurality of backscattered signals from the transducer at a receive bit rate of at least 200 Msps and at a receive bit depth of at least 12 bits, wherein a receive signal comprises the plurality of backscattered signals; filter the plurality of backscattered signals based on one or more characteristics of the at least one of the first transmit waveform and the second transmit waveform, wherein at least one of the plurality of backscattered signals is filtered with a decoding filter for the at least one of the first transmit waveform and the second transmit waveform that comprises coded phases that are nonlinear with time; temporally interleave the two or more digital transmit signals and the plurality of backscattered signals and combine the filtered plurality of backscattered signals into single lines of an image; and generate an intravascular ultrasound (IVUS) image based on a plurality of the single lines of the image; an ultrasound control board comprising: a digital-to-analog converter configured to convert the two or more digital transmit signals to analog; and an analog-to-digital converter configured to convert the receive signal from the transducer to digital;a catheter interface module configured to be placed in at least one of a mechanical and electrical communication with the imaging core; and a system cable configured to connect the catheter interface module to the workstation.

2. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein: the catheter body has a length of at least 177 centimeters, the catheter body comprising: a lumen; a working length portion having a length of at least 90 centimeters; and a proximal extension having a length of at least 1 centimeter; the transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal; wherein the catheter interface module comprises a linear high-power transmit amplifier configured to amplify the two or more digital transmit signals.

3. The intravascular ultrasound (IVUS) catheter system of claim 2, wherein the catheter interface module further comprises: a selectable impedance matching module configured to transform an impedance of the linear high- power transmit amplifier to match an input impedance of a signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal.

4. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the at least one of the first transmit waveform and the second transmit waveform has coded instantaneous frequencies versus time that are nonlinear with time.

5. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the coded phases comprise a nonlinear phase with time.

6. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the workstation is configured to operate under voice control.

7. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the workstation is configured for image analysis using an artificial intelligence algorithm to identify a vessel border.

8. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the workstation is configured to determine blood flow proximate to the catheter body.

9. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the workstation is configured for image analysis using an artificial intelligence algorithm to identify blood or a location or a type of plaque, calcium, stent apposition, thrombus, or dissection in a vascular system.

10. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the transducer, when placed only in a first blood vessel provides visualization of both said first blood vessel and a second blood vessel, thereby providing visualization of both the first blood vessel and second blood vessel simultaneously and in real time.

11. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the controller comprises at least one processor configured to transmit signals at a bit depth of at least 10 bits.

12. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the transducer.

13. The intravascular ultrasound (IVUS) catheter system of claim 1, wherein the catheter interface module includes a slip ring with a non-electrically conductive coupling shaft connected to the slip ring.

14. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the workstation combines the receive signal from at least one of the first transmit waveform and the second transmit waveform into a single image line through replacing a range of echoes from one line with backscattered echoes from another line.

15. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the workstation combines the receive signal from at least one of the first transmit waveform and the second transmit waveform into a single image line through replacing a range of echoes from one line with a blended combination of echoes from the received signals from the first and second transmit waveforms.

16. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the workstation combines receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes after linearly interpolating analytically between two lines over a same distance.

17. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and wherein the system cable is configured for multiple time interleaved functions per shielded twisted pair (STP).

18. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the catheter interface module is configured to be placed outside of a sterile field.

19. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the catheter interface module further comprises a motor and a motor control module configured to monitor a position of the motor.

20. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, further comprising a non-volatile electronic memory configured to store at least one of a part number, an identification, usage monitoring, a security copy protection, and catheter-specific acoustic data retrieval.

21. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, further comprising a precise motor control configured for improving image visual stability and enabling line density control for subsections within a 360 degree image.

22. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the system is configured for reduction of non-uniform rotational distortion (NURD).

23. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the digital-to- analog converter is high-fidelity and wherein the analog-to-digital converter is oversampled by at least a factor of two.

24. The intravascular ultrasound (IVUS) catheter system of claim 3, wherein the low noise amplifier is configured with at least a gain of 20 dB with a noise figure less than or equal to 1.2 dB over a frequency bandwidth of 5 to 90 MHz.

25. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the system is configured to: automatically calculate one or more measurements of a vascular lumen from an IVUS image imaged by the imaging core, automatically identify an edge of the vascular lumen; calculate one or more confidence values associated with one or more sections of the edge of the vascular lumen; and provide a graphical representation of the edge of the vascular lumen to be displayed in real time as an overlay on the IVUS image, wherein the graphical representation of the edge of the vascular lumen is divided into the one or more sections of the edge of the vascular lumen based on the one or more confidence values associated with each of the one or more sections of the edge of the vascular lumen.

26. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the system is configured for image analysis using an artificial intelligence algorithm to identify at least one of a vessel lumen and a vessel border.

27. The intravascular ultrasound (IVUS) catheter system of any one of claims 1 - 12, wherein the system is configured for image analysis using an artificial intelligence algorithm to identify blood or a location or a type of at least one of plaque, thrombus, calcium, and vessel dissection in a peripheral, neuro and / or coronary vascular system.

28. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body, the catheter body comprising: a lumen; a working length portion; anda proximal extension; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an imaging electrical core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to generate a digital high speed, high bit count transmit signal; and an ultrasound control board comprising a high-fidelity digital-analog converter configured to convert the transmit signal to analog; a catheter interface module configured to be placed in electrical communication with the imaging core via the imaging electrical core wire, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a system cable configured to connect the catheter interface module to the workstation.

29. The Intravascular ultrasound (IVUS) catheter system of claim 28, wherein the working length portion has a range of 90 – 210 centimeters in length and the proximal extension has a range of 1 – 120 centimeters in length.

30. The intravascular ultrasound (IVUS) catheter system of claim 28, wherein the controller is configured to generate the transmit signals at a bit rate greater than or equal to 200 megasamples per second (Msps).

31. The intravascular ultrasound (IVUS) catheter system of any one of claims 28 - 30, wherein at least one processor is configured to transmit signals at a bit depth of at least 104 bits.

32. The intravascular ultrasound (IVUS) catheter system of any one of claims 28 - 30, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

33. The intravascular ultrasound (IVUS) catheter system of any one of claims 28 - 30, wherein the catheter interface module is configured to be placed outside of a sterile field.

34. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body, the catheter body comprising: a lumen; a working length portion; and a proximal extension; an imaging core disposed in the lumen of the catheter body, the imaging core comprising:a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an imaging electrical core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to generate a digital high speed, high bit count transmit signal; and an ultrasound control board comprising a high-fidelity digital-analog converter configured to convert the transmit signals to analog; a catheter interface module configured to be placed in at least one of mechanical and electrical communication with the imaging core via the imaging electrical core wire and the workstation, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a selectable impedance matching module configured to transform an electrical impedance of the transmit amplifier to match an input impedance of a signal path to the imaging core; and a system cable configured to connect the catheter interface module to the workstation.

35. The intravascular ultrasound (IVUS) catheter of claim 34, wherein the working length is at least 105 centimeters.

36. The intravascular ultrasound (IVUS) catheter of claim 35, wherein: a distal working length portion has a range of 90 – 210 centimeters in length; and the proximal extension has a range of 1 – 120 centimeters in length.

37. The intravascular ultrasound (IVUS) catheter system of any one of claims 34-36, wherein the controller is configured to generate the transmit signals at a bit rate greater than or equal to 200 megasamples per second (Msps).

38. The intravascular ultrasound (IVUS) catheter system of any one of claims 34-36, wherein the controller comprises at least one processor that is configured to transmit the signals at a bit depth of at least 10 bits.

39. The intravascular ultrasound (IVUS) catheter system of any one of claims 34-36, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

40. The intravascular ultrasound (IVUS) catheter system of any one of claims 34-36, wherein the catheter interface module is configured to be placed outside of a sterile field.

41. The intravascular ultrasound (IVUS) catheter system of any one of claims 34-36, wherein the catheter interface module further comprises a motor and a motor control module configured to monitor a position of the motor.

42. The intravascular ultrasound (IVUS) catheter system of any one of claims 34-36, comprising a non-volatile electronic memory configured to store part number, identification, usage monitoring, security (copy protection), and / or catheter-specific acoustic data retrieval.

43. The intravascular ultrasound (IVUS) catheter system of any one of claims 34-36, comprising a precise motor control configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image.

44. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body, comprising: a lumen; a working length portion; and a proximal extension; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an imaging electrical core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to: generate a digital transmit signal at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits; and receive a receive signal from the transducer at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits; an ultrasound control board comprising: a high-fidelity digital-to-analog converter configured to convert the transmit signal to analog; and an oversampled analog-to-digital converter configured to convert the receive signal from the transducer to digital; a catheter interface module configured to be placed in at least one of mechanical and electrical communication with the imaging core via the imaging electrical core wire and the workstation, the catheter interface module comprising:a linear high-power transmit amplifier configured to amplify the transmit signal; a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match an input impedance of a signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal; and a system cable configured to connect the catheter interface module to the workstation.

45. The intravascular ultrasound (IVUS) catheter of claim 44, wherein the working length is at least 105 centimeters.

46. The intravascular ultrasound (IVUS) catheter of claim 45, wherein: wherein the catheter body has a length of at least 177 cm; a distal working length portion has a range of 90 – 210 centimeters in length; and the proximal extension has a range of 1 – 120 centimeters in length.

47. The intravascular ultrasound (IVUS) catheter system of any one of claims 44-46, wherein at least one processor is configured to transmit signals at a bit depth of at least 10 bits.

48. The intravascular ultrasound (IVUS) catheter system of any one of claims 44-46, wherein the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the transducer.

49. The intravascular ultrasound (IVUS) catheter system of any one of claims 44-46, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

50. The intravascular ultrasound (IVUS) catheter system of any one of claims 44-46, wherein the catheter interface module is configured to be placed outside of a sterile field.

51. The intravascular ultrasound (IVUS) catheter system of any one of claims 44-46, wherein the catheter interface module further comprises a motor and a motor control module configured to monitor a position of the motor.

52. The intravascular ultrasound (IVUS) catheter system of any one of claims 44-46, comprising a non-volatile electronic memory configured to store part number, identification, usage monitoring, security (copy protection), and / or catheter-specific acoustic data retrieval.

53. The intravascular ultrasound (IVUS) catheter system of any one of claims 44-46, comprising a precise motor control configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image.

54. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body, the catheter body comprising: a lumen; a working length portion; and a proximal extension; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an electrical wire; a workstation comprising: a controller configured to: generate two or more digital transmit signals each at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits, the transmit signals comprising at least two waveforms comprising a first waveform and a second waveform, the first waveform having a longer duration than the second waveform; receive backscattered signals from the transducer at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits, the receive signal comprising a plurality of backscatter signals; filter the plurality of backscatter signals based on one or more characteristics of the plurality of different transmit waveforms; a sequencer controller to temporally interleave paired transmit and receive events and combine pairs of filtered backscattered echoes into single lines of an image; and generate an IVUS image based on the plurality of image lines; an ultrasound control board comprising: a high-fidelity digital-to-analog converter configured to convert the transmit signal to analog; and an oversampled analog-to-digital converter configured to convert the receive signal from the transducer to digital;a catheter interface module configured to be placed in at least one of mechanical and electrical communication with the imaging core and the workstation, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal; and a system cable configured to connect the catheter interface module to the workstation.

55. The intravascular ultrasound (IVUS) catheter of claim 54, wherein the working length is at least 105 centimeters.

56. The intravascular ultrasound (IVUS) catheter of claim 55, wherein: a distal working length portion has a range of 90 – 210 centimeters in length; and the proximal extension has a range of 1 – 120 centimeters in length.

57. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein at least one processor is configured to transmit the signals at a bit depth of at least 14 bits.

58. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the ultrasound transducer.

59. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the workstation combines the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes from one line with the receive echoes from another line.

60. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the workstation combines the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes from one line with a blended combination of echoes from the two or more lines.

61. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the workstation combines the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes after linearly interpolating analytically between two lines over a same distance.

62. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the systemcable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

63. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the catheter interface module is configured to be placed outside of a sterile field.

64. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the catheter interface module is configured to be placed inside of a sterile field within a sterile bag.

65. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, wherein the catheter interface module further comprises a motor and a motor control module configured to monitor a position of the motor.

66. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, comprising a non-volatile electronic memory configured to store part number, identification, usage monitoring, security (copy protection), and / or catheter-specific acoustic data retrieval.

67. The intravascular ultrasound (IVUS) catheter system of any one of claims 54-56, comprising a precise motor control configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image.

68. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body having a length of at least 177 centimeters, the catheter body comprising: a lumen; a working length portion having a length of at least 90 centimeters; and a proximal extension having a length of at least 1 centimeter; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an electrical wire; a workstation comprising: a controller configured to: generate two or more digital transmit signals each at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits, the transmit signals comprising at least two different waveforms, wherein the at least two waveforms comprise a longer waveform, and a coded waveform with coded phases that are nonlinear with time;receive backscattered signals from the transducer at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits, the receive signal comprising a plurality of backscatter signals; filter the plurality of backscatter signals based on one or more characteristics of the plurality of different transmit waveforms, one with a decoding filter for the coded transmit signals; a sequencer controller to temporally interleave paired transmit and receive events and combine the pairs of filtered backscattered echoes into single lines of an image; and generate an IVUS image based on the plurality of image lines; an ultrasound control board comprising: a high-fidelity digital-to-analog converter configured to convert the transmit signal to analog; and an oversampled analog-to-digital converter configured to convert the receive signal from the transducer to digital; a catheter interface module configured to be placed in at least one of a mechanical and electrical communication with the imaging core and the workstation, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core; a low noise amplifier configured to modify the receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal; and a system cable configured to connect the catheter interface module to the workstation.

69. The intravascular ultrasound (IVUS) catheter system of claim 68, wherein the two or more different waveforms in the controller are different where one is longer than the other and one has coded instantaneous frequencies versus time that are nonlinear with time.

70. The intravascular ultrasound (IVUS) catheter system of claim 68, wherein the two or more different waveforms in the controller are different where one is longer than the other and one has coded instantaneous frequencies versus time that are linear with time.

71. The intravascular ultrasound (IVUS) catheter system of claim 68, wherein at least one processor is configured to transmit the signals at a bit depth of at least 10 bits.

72. The intravascular ultrasound (IVUS) catheter system of claim 68, wherein the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the ultrasound transducer.

73. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, wherein the workstation combines the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes from one line with the receive echoes from another line.

74. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, wherein the workstation combines the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes from one line with a blended combination of echoes from the two or more lines.

75. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, wherein the workstation combines the receive echoes from two or more different transmit waveforms into a single image line through replacing a range of echoes after linearly interpolating analytically between two lines over a same distance.

76. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

77. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, wherein the catheter interface module is configured to be placed outside of a sterile field.

78. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, wherein the catheter interface module further comprises a motor and a motor control module configured to monitor a position of the motor.

79. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, comprising a non- volatile electronic memory configured to store part number, identification, usage monitoring, security (copy protection), and / or catheter-specific acoustic data retrieval.

80. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, comprising a precise motor control configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image.

81. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, configured for reduction of non-uniform rotational distortion (NURD).

82. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, configured to: automatically calculate one or more measurements of a vascular lumen from an IVUS image imaged by the imaging core, automatically identify an edge of the vascular lumen;calculate one or more confidence values associated with one or more sections of the edge of the vascular lumen; and provide a graphical representation of the edge of the vascular lumen to be displayed in real time as an overlay on the IVUS image, wherein the graphical representation of the edge of the vascular lumen is divided into the one or more sections of the edge of the vascular lumen based on the one or more confidence values associated with each of the one or more sections of the edge of the vascular lumen.

83. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, configured for image analysis using an artificial intelligence algorithm to identify at least one of a vessel lumen and a vessel border.

84. The intravascular ultrasound (IVUS) catheter system of any one of claims 68 - 72, configured for image analysis using an artificial intelligence algorithm to identify blood or a location or a type of at least one of plaque, thrombus, calcium, and vessel dissection in a peripheral, neuro and / or coronary vascular system.

85. An intravascular ultrasound (IVUS) catheter system comprising: a workstation comprising a controller configured to: generate two or more digital transmit signals at a transmit bit rate of at least 200 megasamples per second (Msps) and a transmit bit depth of at least 10 bits, the two or more digital transmit signals comprising at least a first transmit waveform and a second transmit waveform, wherein the first transmit waveform is longer than the second transmit waveform, wherein at least one of the first transmit waveform and the second transmit waveform comprises coded phases that are nonlinear with time; receive a plurality of backscattered signals from a transducer at a receive bit rate of at least 200 Msps and / when at a receive bit depth of at least 12 bits, wherein a receive signal comprises the plurality of backscattered signals; filter the plurality of backscatter signals based on one or more characteristics of the at least one of the first transmit waveform and the second transmit waveform, wherein at least one of the plurality of backscatter signals is filtered with a decoding filter for the at least one of the first transmit waveform and the second transmit waveform that comprises coded phases that are nonlinear with time; a sequencer controller to temporally interleave the two or more digital transmit signals and the plurality of backscattered signals and combine the filtered plurality of backscattered signals into single lines of an image; and generate an intravascular ultrasound (IVUS) image based on a plurality of the single lines of the image; an ultrasound control board comprising:a digital-to-analog converter configured to convert the two or more digital transmit signals to analog; and an analog-to-digital converter configured to convert the receive signal from the transducer to digital.

86. An ultrasound system comprising: a interface module comprising: a linear high-power transmit amplifier configured to amplify two or more digital transmit signals; a selectable impedance matching module configured to transform an impedance of the linear high-power transmit amplifier to match an input impedance of a signal path to an imaging core; a low noise amplifier configured to modify a receive signal; a variable gain amplifier configured to modify the receive signal; a field programmable gate array configured to: create a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and instruct the variable gain amplifier to apply the time gain compensation profile to the receive signal.

87. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body comprising a lumen; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, a cable configured to rotate the transducer, the cable comprising a proximal portion, a distal portion, and a connector hub configured to connect the proximal portion and the distal portion; and an electrical wire; a catheter interface module configured to be placed in at least one of mechanical and electrical communication with the imaging core, the catheter interface module comprising: a controller configured to transmit high speed, high bit count transmit signals; a high-fidelity digital-to-analog converter configured to convert the transmit signals to an analog transmit signal; and a linear high-power transmit amplifier configured to amplify the analog transmit signal; and a cable configured to place the catheter interface module in electrical contact with an ultrasound control board.

88. An intravascular ultrasound (IVUS) catheter system comprising:a catheter body comprising a lumen; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an imaging electrical core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to generate a digital high speed, high bit count transmit signal; and an ultrasound control board comprising a high-fidelity digital-to-analog converter configured to convert the transmit signal to analog; a catheter interface module configured to be placed in electrical communication with the imaging core via the imaging electrical core wire, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a system cable configured to connect the catheter interface module to the workstation.

89. The intravascular ultrasound (IVUS) catheter system of claim 88, wherein the catheter body comprises a length of at least 177 centimeters.

90. The intravascular ultrasound (IVUS) catheter system of claim 89, wherein the catheter body further comprises: a distal working length portion that has a range of 90 – 210 centimeters in length; and a proximal extension that has a range of 1 – 120 centimeters in length.

91. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, wherein the controller is configured to generate the transmit signals at a bit rate greater than or equal to 200 megasamples per second (Msps).

92. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, wherein at least one processor is configured to transmit the signals at a bit depth of at least 10 bits.

93. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, wherein the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the ultrasound transducer.

94. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

95. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, wherein the catheter interface module is configured to be placed outside of a sterile field.

96. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, wherein the catheter interface module is configured to be placed inside of a sterile field within a sterile bag.

97. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, wherein the catheter interface module further comprising a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match an input impedance of a signal path to the imaging core.

98. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, comprising a non-volatile electronic memory configured to store part number, identification, usage monitoring, security (copy protection), and / or catheter-specific acoustic data retrieval.

99. The intravascular ultrasound (IVUS) catheter system of any one of claims 88-90, comprising a precise motor control configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image.

100. An intravascular ultrasound (IVUS) catheter system comprising: a catheter body comprising a lumen; an imaging core disposed in the lumen of the catheter body, the imaging core comprising: a transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal, an imaging core cable configured to rotate the transducer; and an imaging coaxial core wire configured to transmit electrical signals to and from the transducer; a workstation comprising: a controller configured to generate a digital high speed, high bit count transmit signal; and an ultrasound control board comprising a high-fidelity digital-to-analog converter configured to convert the transmit signal to analog; a catheter interface module configured to be placed in electrical communication with the imaging core via the imaging electrical core wire, the catheter interface module comprising: a linear high-power transmit amplifier configured to amplify the transmit signal; and a system cable configured to connect the catheter interface module to the workstation.

101. A catheter interface module, comprising: a linear high-power transmit amplifier configured to amplify a transmit signal; and a selectable impedance matching module configured to transform an impedance of the transmit amplifier to match the input impedance of the signal path to an imaging core,wherein the catheter interface module configured to be placed in at least one of mechanical and electrical communication with an imaging core and a workstation.

102. An ultrasound system comprising the catheter interface module of Claim 101, and further comprising at least one of the following: a controller configured to generate a digital high speed, high bit count transmit signal; and / or a high-fidelity digital-to-analog converter configured to convert the transmit signals to analog.

103. A method for intravascular ultrasound (IVUS) imaging, the method comprising: providing an intravascular ultrasound (IVUS) catheter having a length of at least 177 centimeters, the IVUS catheter comprising: a lumen; a working length portion having a length of at least 90 centimeters; a proximal extension having a length of at least 1 centimeter; a transducer disposed within the lumen, the transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal; and converting the digital transmit signal to analog using a digital-to-analog converter; and amplifying the transmit signal using a linear high-power transmit amplifier.

104. The method of claim 103, wherein the working length portion of the IVUS catheter is between about 90 centimeters and about 210 centimeters in length, and wherein the proximal extension of the IVUS catheter is between about 1 centimeter and about 120 centimeters in length.

105. The method of claim 103, wherein generating the transmit signal comprises generating the transmit signal at a bit rate greater than or equal to 200 megasamples per second (Msps).

106. The method of any one of claims 103-105, wherein generating the transmit signal comprises generating the transmit signal at a bit depth of at least 10 bits.

107. The method of any one of claims 103-105, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

108. The method of any one of claims 103-105, wherein the catheter interface module is configured to be placed outside of a sterile field.

109. The method of any one of claims 103-105, wherein the catheter interface module is configured to be placed inside of a sterile field within a sterile bag.

110. A method for intravascular ultrasound (IVUS) imaging, the method comprising: providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen, the transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal; and converting the digital transmit signal to analog using a digital-to-analog converter; amplifying the transmit signal using a linear high-power transmit amplifier; and transforming an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core.

111. The method of Claim 110, wherein the IVUS catheter comprises a length of at least 177 centimeters.

112. The method of Claim 110, wherein the IVUS catheter comprises: a working length portion having a length between about 90 centimeters and about 210 centimeters; and a proximal extension having a length between about 1 centimeter and about 120 centimeters.

113. The method of any one of Claims 110-112, wherein generating the transmit signal comprises generating the transmit signal at a bit rate greater than or equal to 200 megasamples per second (Msps).

114. The method of any one of Claims 110-112, wherein generating the transmit signal comprises generating the transmit signal at a bit depth of at least 14 bits.

115. The method of any one of Claims 110-112, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

116. The method of any one of Claims 110-112, wherein the catheter interface module is configured to be placed outside of a sterile field.

117. The method of any one of Claims 110-112, wherein the catheter interface module is configured to be placed inside of a sterile field within a sterile bag.

118. The method of any one of Claims 110-112, wherein the catheter interface module further comprises a motor and a motor control module, and wherein the method further comprises monitoring a position of the motor.

119. A method for intravascular ultrasound (IVUS) imaging, the method comprising: providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen, the transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal at a transmit bit rate of at least 200 Megasamples per second (Msps) and a transmit bit depth of at least 10 bits; converting the digital transmit signal to analog using a digital-to-analog converter; amplifying the transmit signal using a linear high-power transmit amplifier; transforming an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core; producing at least one pulse-echo from the transducer based on the transmit signal; receiving, at the transducer, a receive signal at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits; converting the receive signal from analog to digital via an oversampled analog-to-digital converter; amplifying the receive signal via a low noise amplifier; creating, via a field programmable gate array, a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; and applying the time gain compensation profile to the receive signal via a variable gain amplifier.

120. The method of Claim 119, wherein the IVUS catheter comprises a length of at least 177 centimeters.

121. The method of Claim 119, wherein the IVUS catheter comprises: a working length portion having a length between about 90 centimeters and about 210 centimeters; and a proximal extension having a length between about 1 centimeter and about 120 centimeters.

122. The method of any one of Claims 119-121, wherein the transmit bit depth is at least 14 bits.

123. The method of any one of claims 119-121, wherein the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the ultrasound transducer.

124. The method of any one of Claims 119-121, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

125. The method of any one of Claims 119-121, wherein the catheter interface module is configured to be placed outside of a sterile field.

126. The method of any one of Claims 119-121, wherein the catheter interface module further comprises a motor and a motor control module, and wherein the method further comprises monitoring a position of the motor.

127. A method for intravascular ultrasound (IVUS) imaging, the method comprising: providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen, the transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal; an imaging core cable configured to rotate the transducer; an imaging electrical core wire transmit electrical signals to and from the transducer; placing the IVUS catheter in electronic communication with a catheter interface module and a workstation, via a system cable; generating, via the workstation, a digital high speed, high bit count transmit signal at a transmit bit rate of at least 200 Megasamples per second (Msps) and a transmit bit depth of at least 10 bits, wherein the transmit signal comprises a plurality of coded waveforms; converting the digital transmit signal to analog using a digital-to-analog converter; amplifying the transmit signal using a linear high-power transmit amplifier; transforming an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core; producing at least one pulse-echo from the transducer based on the transmit signal; receiving, at the transducer, a receive signal at a receive bit rate of at least 200 Msps at a receive bit depth of at least 12 bits, wherein the receive signal comprising a plurality of backscatter signals; converting the receive signal from analog to digital via an oversampled analog-to-digital converter; amplifying the receive signal via a low noise amplifier; creating, via a field programmable gate array, a time gain compensation profile based on one or more characteristics of the receive signal and a plurality of pre-programmed time gain compensation profiles; applying the time gain compensation profile to the receive signal via a variable gain amplifier; filtering the plurality of backscatter signals based on one or more characteristics of the one or more coded waveforms;decoding the plurality of backscatter signals based on the one or more characteristics of the one or more coded waveforms to generate a plurality of image lines; and generating an IVUS image based on the plurality of image lines.

128. The method of Claim 127, wherein the IVUS catheter comprises a length of at least 177 centimeters.

129. The method of Claim 127, wherein the IVUS catheter comprises: a working length portion having a length between 90 centimeters and 210 centimeters; and a proximal extension having a length between 1 centimeter and 120 centimeters.

130. The method of any one of Claims 127-129, wherein the transmit bit depth is at least 14 bits.

131. The method of any one of claims 127-129, wherein the catheter interface module includes a slip ring where two or more brush and ring pairs are connected to each single wire conductor of the ultrasound transducer.

132. The method of any one of Claims 127-129, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

133. The method of any one of Claims 127-129, wherein the catheter interface module is configured to be placed outside of a sterile field.

134. The method of any one of Claims 127-129, wherein the catheter interface module is configured to be placed inside of a sterile field within a sterile bag.

135. The method of any one of Claims 127-129, wherein the catheter interface module further comprises a motor and a motor control module, and wherein the method further comprises monitoring a position of the motor.

136. A method for intravascular ultrasound (IVUS) imaging, the method comprising: providing an IVUS catheter, the IVUS catheter comprising: a lumen; a transducer disposed within the lumen, the transducer comprising at least one of: monolithic lead zirconate titanate, composite lead zirconate titanate, a capacitive micromachine ultrasonic transducer, a piezoelectric micromachined ultrasonic transducer, and a single crystal; and an imaging core cable configured to rotate the transducer, the cable comprising a proximal portion, a distal portion, and a connector hub configured to connect the proximal portion and the distal portion; providing a catheter interface module, the catheter interface module configured to be placed in at least one of mechanical and electrical communication with the transducer; connecting the catheter interface module and the IVUS catheter in electrical communication with an ultrasound system control board via a system cable; generating, via a controller, a high speed, high bit count signals; converting the signals from digital to analog via a digital-to-analog converter; andamplifying the signals via a linear high-power transmit amplifier.

137. The method of Claim 136, wherein the IVUS catheter comprises a length of at least 177 centimeters.

138. The method of Claim 136, wherein the IVUS catheter comprises: a working length portion having a length between 90 centimeters and 210 centimeters; and a proximal extension having a length between 1 centimeter and 120 centimeters.

139. The method of Claim 136, wherein generating the transmit signal comprises generating the transmit signal at a bit rate greater than or equal to 200 megasamples per second (Msps).

140. The method of any one of Claims 136-139, wherein generating the transmit signal comprises generating the transmit signal with a transmit bit depth is at least 14 bits.

141. The method of any one of Claims 136-139, wherein the system cable comprises a length of 5 meters or more, and an outer diameter of 10 millimeters or less, and wherein the system cable is configured to be tolerant to environmental noise sources and design with multiple time-interleaved functions per STP inner cable.

142. The method of any one of Claims 136-139, wherein the catheter interface module is configured to be placed outside of a sterile field.

143. The method of any one of Claims 136-139, wherein the catheter interface module is configured to be placed inside of a sterile field within a sterile bag.

144. The method of any one of Claims 136-139, wherein the catheter interface module further comprises a motor and a motor control module, and wherein the method further comprises monitoring a position of the motor.

145. The method of any one of Claims 136-139, wherein the method further comprises transforming an impedance of the transmit amplifier to match the input impedance of the signal path to the imaging core cable.

146. A method of facilitating signal transmission along a device that would otherwise cause distortion, comprising: processing for high speed signals, converting the high speed signals from digital to analog, and amplifying the high speed signals with a high-power transmit amplifier.

147. A kit, comprising one or more of the catheters, hubs, seals, plugs as described herein along with instructions for use.

148. A use of any of the devices, systems and methods according to any one of the preceding claims for imaging without any therapy.

149. A use of any of the devices, systems and methods according to any one of the preceding claims for imaging before, after or simultaneously with using ultrasound as a therapy on the same or different system.

150. A use of any of the devices, systems and methods according to any one of the preceding claims, wherein the term “IVUS catheter” is replaced with ultrasound imaging device, and such device is used to image a non-vessel lumen, cavity or organ.

151. A use of any of the devices, systems and methods according to any one of the preceding claims for imaging before, after and / or simultaneously with using non-ultrasound technology as a therapy, wherein said non- ultrasound technology comprises mechanical thrombectomy and / or an interventional coronary procedure.

152. A use of any of the devices, systems and methods according to any one of the preceding claims for minimally-invasive imaging.

153. A use of any of the devices, systems and methods according to any one of the preceding claims for imaging of intravascular tissue for identifying irregularities, disease, and / or injury for medical treatment.

154. A use of any of the devices, systems and methods according to any one of the preceding claims for identification of lesions, plaque, thrombus, calcium buildup, dissections, and measurement of these abnormalities.

155. A use of any of the devices, systems and methods according to any one of the preceding claims, comprising a non-volatile electronic memory configured to store part number, identification, usage monitoring, security (copy protection), and / or catheter-specific acoustic data retrieval.

156. A use of any of the devices, systems and methods according to any one of the preceding claims, comprising a precise motor control configured for improving image visual stability and / or enabling line density control for subsections within a 360 degree image.

157. A use of any of the devices, systems and methods according to any one of the preceding claims configured for image analysis using an artificial intelligence algorithm to identify a tissue border, plaque, calcium, thrombus, dissection, and / or stent apposition.

158. A use of any of the devices, systems and methods according to any one of the preceding claims configured for reduction of non-uniform rotational distortion (NURD).

159. A use of any of the devices, systems and methods according to any one of the preceding claims for imaging and optionally visualizing and detecting the boundaries of an abnormality, such as an abnormal tissue growth, wherein such growth is a benign or cancerous cyst or tumor, and wherein the tumor includes, for example, fibroids and polyps including but not limited to those located in reproductive organs such as the uterus, the nasal or ear cavity, rectum, colon, other intestinal regions or elsewhere.

160. A method of 2D and / or 3D imaging of collateral vessels and / or side branches having one or more of the features described in the foregoing description.

161. An ultrasound transducer having one or more of the features described in the foregoing description.

162. A method of imaging with ultrasound having one or more of the features described in the foregoing description.

163. A method of manufacture of any of the devices and systems having one or more of the features described in the foregoing description.

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