Systems and methods for manually assisted movement for spatially aligned lengthwise measurements in intravascular ultrasound imaging

Abstract

Systems and methods described herein are directed to methods of measuring distance along vasculature with intravascular ultrasound imaging. Several embodiments advantageously do not depend on fully automatic common registration with another imaging modality such as angiography, radioscopy or fluoroscopy. More particularly, the processor may detect longitudinal movement of the catheter based on detection of a marker disposed on the catheter based on a pacing input provided by a user and / or a pacing instruction output by the system to the user corresponding to the marker movement. The processor may associate and annotate the IVUS image with a longitudinal position of the marker as the IVUS image is captured. An encoder may also be deployed to reduce dependency on another imaging modality.

Description

Cross-references to related applications

[0001] This application claims the benefit of U.S. Provisional Application No. US App. 63 / 531,266, filed August 7, 2023, entitled “System and method for manually assisted pullback for spatial alignment length measurement in intravascular ultrasound imaging,” the entire contents of which are hereby incorporated herein by reference in their entirety. Technical Field

[0002] This disclosure relates to the field of ultrasound, such as the use of ultrasound for medical diagnostic and imaging applications. Background Technology

[0003] Ultrasound imaging transducers, including those used for intraluminal imaging, emit and receive sound waves to generate images based on reflections from objects near the transducer, such as tissue. Some standard IVUS catheters rely on motorized axial translation with attachments such as motors and translation mechanisms to measure the length and distance of IVUS images between imaging tissue features across the intraluminal axis. Summary of the Invention

[0004] In several embodiments, intravascular ultrasound (IVUS) imaging is provided, for example, manually assisted longitudinal movement of an IVUS catheter for spatial longitudinal alignment measurements of tissue using IVUS imaging, such as distance-based length measurements along an intraluminal axis within the patient. Movements such as longitudinal and / or axial movement include pulling or retracting the catheter from the vessel or other lumen, pushing or otherwise advancing the catheter into the vessel or other lumen, or both.

[0005] Diagnosis, measurement, and imaging of intraluminal tissue are crucial for identifying irregularities, diseases, and / or injuries for medical treatment and can improve patient outcomes. Measurement of the dimensions (e.g., length, width, thickness) of intravascular lesions such as plaques (e.g., hard plaques, soft plaques, vulnerable plaques, calcified plaques, substantially non-calcified plaques) or thrombi facilitates diagnosis and stent preparation, and enables medical professionals (e.g., internists, surgeons, and / or medical technicians from various fields) to plan treatments such as vascular surgery and / or interventional cardiology that traverse the body from the heart to the peripheral vascular system. In several embodiments, the use of the IVUS imaging improvements described herein has enabled intravascular imaging-guided percutaneous interventions targeting peripheral vascular or coronary artery lesions in arteries and / or veins. Imaging, measuring, and diagnosing intraluminal tissues (e.g., intravascular, luminal, digestive tract, esophagus, stomach, intestine, rectum, sinus, ureter, bladder, gynecological, cardiac, etc.) helps identify irregularities, diseases, and / or injuries for medical treatment to improve patient outcomes. Once an abnormality is identified, appropriate treatment can be administered to the patient. For example, image-guided therapies can be used for tumors, thrombi, plaques, etc., where imaging and therapeutic capabilities are present on a single device or multiple devices. Several embodiments include, for example, percutaneous coronary intervention for coronary artery disease, intravascular imaging-guided percutaneous intervention for peripheral vascular disease, and / or intravascular imaging-guided percutaneous intervention in arteries and / or veins. In several embodiments, the IVUS system is configured for optimized peripheral vascular surgery. In several embodiments, the IVUS system is configured for optimized peripheral vascular surgery and not for coronary vascular surgery. In several embodiments, the IVUS system is configured for coronary artery surgery. In several embodiments, the IVUS system is configured for neurovascular surgery (including, but not limited to, cerebrovascular surgery). In several embodiments, the IVUS system is configured for IVUS-guided thrombectomy, including but not limited to mechanical thrombectomy. In some embodiments, the IVUS system is configured for ultrasound-guided pulmonary embolization resection. In several embodiments, simultaneous, real-time IVUS guidance is provided for procedures such as thrombectomy / embolization resection, stent placement, clot aspiration, other coronary or neurovascular surgeries, etc. Although several embodiments described herein describe IVUS, the techniques described herein are also used for intraluminal imaging (in addition to intravascular imaging). For example, several embodiments are used for imaging, diagnosing, and / or providing image-guided interventions of the digestive tract, esophagus, stomach, intestine, rectum, sinus, ureter, bladder, uterus, fallopian tubes, lungs, brain, etc. The systems and methods described herein can be used in conjunction with endoscopy rather than IVUS catheters and support the identification and diagnosis of gastrointestinal tumors, such as tumors in the intestine and / or bile ducts. Similarly, the systems and methods described herein can be used for imaging sinus cavities using IVUS.In various embodiments, IVUS uses ultrasound only for imaging (no therapy). In various embodiments, IVUS uses ultrasound only for therapy (no imaging). In various embodiments, IVUS uses both ultrasound for imaging and therapy. According to several embodiments, one or more imaging techniques as described herein can be combined with one or more therapeutic elements on the same catheter, such as an integrated ultrasound imaging element located at or near the end of a thrombectomy device (or otherwise along the thrombectomy device). The thrombectomy device can also be a separate device delivered before, during, or after the imaging device. The thrombectomy device can be a mechanical clot removal device, a clot aspiration device, or a combination of clot removal and aspiration. In several embodiments, the ultrasound imaging devices and methods disclosed herein, along with (integrated or separate) clot therapy devices, are used to treat neurovascular, coronary, and pulmonary clots. The clot therapy device may also include, for example, non-mechanical devices, such as thrombolytic or other drug delivery devices and energy delivery devices, to disrupt / eliminate the clot or otherwise restore blood flow. Combinations of two, three, or more therapies (e.g., ultrasound or laser clot destruction with a thrombolytic agent) are also provided in conjunction with the IVUS imaging technology described herein. According to several embodiments, the integrated IVUS and therapeutic catheter or probe can also be used to restore blood flow not caused by a clot.

[0006] Several embodiments described herein provide systems and methods for determining the longitudinal, longitudinal position of a manually advanced and / or retracted ultrasound imaging catheter, and for measuring the length of longitudinal, longitudinal movement of the ultrasound imaging catheter within a blood vessel, lumen, or other region. Manually assisted longitudinal, longitudinal movement of the IVUS catheter can be achieved for spatial alignment measurements of tissue using IVUS imaging. In several embodiments, distance-based length measurements along an axis within the patient lumen are provided, such as measuring vascular length using distance-based measurements along the vascular axis.

[0007] Several embodiments utilize manual translation of a catheter with an efficient clinical workflow to provide relative position along the axial and / or longitudinal catheter dimensions during continuous IVUS imaging within human vessels. This positional information allows for measurement of the catheter's longitudinal dimensions relative to the images acquired during translation, without the need for bulky equipment in a sterile environment to actuate catheter movement (e.g., pull-back or advance).

[0008] Advantageously, several embodiments described herein do not require fully automated co-registration with another imaging modality, such as fluoroscopy, in which software algorithms track radiopaque (RO) catheter markers or RO transducers throughout continuous fluoroscopy recording. In several embodiments, systems and methods for IVUS-based measurements do not require integration with another imaging modality and reduce patient exposure to fluoroscopy. For RO markers where weak or low-quality signals may limit accuracy, consistent operator-to-system or system-to-operator interaction may be more reliable than software and / or image-based recognition systems. For example, co-registration with angiography may be used to attempt to shorten procedure time, reduce contrast agent use, and make IVUS more comfortable for the physician. Several embodiments described herein achieve one or more of these benefits without co-registration. In some embodiments, the use of manual movement helps correlate baseline landmarks and waypoints within the patient's body, including in complex situations such as tissue damage, occlusion, lesion size measurements for treatment planning, such as atherosclerosis resection, or stent placement (e.g., determining where an intravascular stent will begin and end). While the systems and methods described herein can still be co-registered, the ability to measure the size of intravascular lesions without automated co-registration allows for greater flexibility in using different components (e.g., components more readily available to physicians and / or components to which physicians have already found a certain level of comfort). In many embodiments, increased surgical speed, reduced healthcare costs, and better patient outcomes can be achieved.

[0009] Several embodiments of image registration described herein utilize synchronized operation and / or measurements from two or more imaging modalities (e.g., ultrasound, X-ray (including radiography, fluoroscopy, angiography, etc.), magnetic resonance imaging, PET scans, optical imaging (e.g., optical coherence tomography, light, laser imaging), etc.) to track the position of the intraluminal catheter with a second imaging modality to determine the relative position between corresponding images in a series of images from both the intraluminal catheter and the second imaging modality. In several embodiments, the user of the IVUS catheter identifies waypoints and reference landmarks and interacts with the IVUS system via inputs or outputs (e.g., voice commands, sounds, tones, beats, vibrations, touch, button clicks, etc.) to synchronize tissue measurements aligned with the second imaging modality. In several embodiments, measurements are synchronized without using one or more of the following: (i) automated computer software that communicates with multiple imaging modalities to identify and track the position of the IVUS catheter to eliminate dependence on user interaction, and (ii) an automated process communicating via a direct, unified link between the imaging modal devices.

[0010] In some embodiments, the use of manual movement helps to correlate baselines and waypoints within the patient’s body, including in complex situations such as tissue damage, occlusion, lesion size measurement for treatment planning, and procedures such as atherosclerosis resection or stent placement (e.g., determining where an intravascular stent will begin and end).

[0011] Fractional flow reserve (FFR) is a minimally invasive surgical technique used to determine the degree of narrowing (stenosis) of coronary arteries by measuring blood pressure and flow in the coronary arteries. The instantaneous waveless ratio (iFR) index is used to assess the severity of coronary artery stenosis by measuring the pressure ratio during a specific diastolic period when coronary artery resistance is relatively minimum and stable. Both FFR and iFR measurements have been found to have similar diagnostic accuracy. According to some embodiments, IVUS imaging and iFR and FFR can be used to identify lesions and other regions of interest, with or without co-registration.

[0012] In several embodiments, intraluminal measurements use imaging to capture images for the diagnosis, measurement, and planning of treatment for a variety of diseases and conditions. In several embodiments, an IVUS catheter system is used to capture images for the diagnosis, measurement, and planning of treatment for a variety of cardiovascular diseases and conditions. When evaluating cardiovascular diseases with an IVUS system, an important data point is the position of one or more transducers at the time of image capture. More specifically, the embodiments described herein allow physicians to determine the longitudinal position of the IVUS catheter and the length or distance of longitudinal movement (e.g., retraction or advancement) of the IVUS catheter within the vessel.

[0013] Advantageously, several embodiments described herein allow for the efficient and effective use of IVUS without the need for bulky accessories, such as motorized pullback devices with translational mechanisms that automatically control the longitudinal, longitudinal, or translational movement of the catheter within a lumen (such as a blood vessel). Other advantages in some embodiments include reduced cost, complexity, and procedure time, because (i) automated length measurement accessories can increase the cost and complexity of using an IVUS system and the time spent preparing for the procedure; and (ii) motorized pullback devices are typically located in a sterile environment and must be sterilized or packaged / bagded with sterile materials before the procedure. Furthermore, automated pullback devices can reduce the amount of fine control and the range of movement of the physician during the procedure compared to IVUS systems that do not employ motorized pullback devices. Several embodiments described herein do not compromise fine control. In several embodiments, the manual movement of the measuring device and method does not involve position sensor devices, such as encoders, for measuring linear movement. In several embodiments, the manual movement of the measuring device and method does not involve mechanically assisted automatic retraction using a telescopic catheter at a pre-set or selected rate, such as a drive mechanism providing movement actuation and position coding, and / or the telescopic catheter providing a specific path for axial movement of the imaging core during automatic mechanical retraction. The embodiments described herein provide systems and methods that offer sufficient accuracy to assist clinical decision-making without requiring the object to reside in a sterile patient environment. Advantages of these embodiments include reduced or eliminated workflow difficulties and a significant reduction in setup time, workload, and complexity for intraluminal measurements.

[0014] In various embodiments, the methods and systems disclosed herein are used to employ manual movement measurement techniques. In one embodiment, manual operation involves using the hand, such as a gloved hand, to control the position of the IVUS catheter. In several embodiments, the manual movement measurement devices and methods do not involve providing powered or automatic translational movement, axial and / or longitudinal movement, or linear movement; they do not have telescopic components, motors for linear movement, or tools that can be engaged with the IVUS catheter to pull it back from or advance it into the patient.

[0015] In various embodiments, systems and methods for detecting the longitudinal and / or elongational position and movement of a manually advanced or retracted catheter are described. Advantageously, in several embodiments, these systems and methods provide more efficient manual control over catheter position when measuring the length within a blood vessel or other lumen using an ultrasound imaging catheter. In some embodiments, the systems and methods provide automatic annotation of IVUS images with longitudinal positional information, such as the location, speed, or length of longitudinal movement. The embodiments described herein eliminate guesswork associated with manually advanced IVUS catheters and improve the workflow of associating IVUS images with intra-body position, for example, by referencing a second imaging modality. In turn, physicians can more effectively provide patients with more reliable or accurate diagnoses and treatments to improve patient outcomes.

[0016] While many embodiments provide for the use of IVUS without translation mechanisms and encoders that automatically control the longitudinal and / or translational movement of the catheter within the lumen, alternative techniques are also provided herein. Examples of such alternative techniques involve capturing and recording a series of IVUS images while manually retracting, withdrawing, inserting, or advancing the catheter along the vessel, simultaneously measuring and recording the relative or absolute insertion depth of the catheter at or near the location where the catheter is inserted into the patient's body using an axial / longitudinal translational position measuring device. In various embodiments, the axial translational position measuring device is an encoder. The encoder can be, for example, one or more of the following: mechanical, optical, inductive, magnetic, electromagnetic capacitive, linear, absolute, incremental, single-channel, incremental, square wave, and / or other position sensing devices. In one embodiment, insertion depth data is used to estimate the spatial position of the images along the length of the vessel in the series. Using this data, the image series can be rendered relative to the length axis. With this spatial alignment, a true volumetric dataset in space can be created and displayed (e.g., two-dimensional or three-dimensional images of radial / diameter versus axial length, which may be referred to as "strip" images). In one embodiment, the image series can be rendered and displayed relative to a longitudinal axis, longitudinal length, or distances between relevant locations within the series. Distances between anatomical points of interest can be obtained with sufficient accuracy, and detailed IVUS images aid in clinical treatment decisions, such as the preferred balloon length and / or expandable stent length for percutaneous endovascular angioplasty.

[0017] According to various embodiments, a method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter includes manually moving the IVUS catheter along its longitudinal axis, wherein the IVUS catheter includes a plurality of markers positioned at predetermined intervals along the length of the longitudinal axis of the IVUS catheter, wherein the plurality of markers are visible in a complementary imaging modality. The method may include capturing multiple images in a complementary imaging modality while moving the IVUS catheter along its longitudinal axis in a proximal or distal direction. The method may include capturing one or more location inputs from a user using a recording device, indicating the position of at least one of the plurality of markers relative to an anatomical point. The method may include associating the one or more location inputs with the plurality of images based on the position of the plurality of markers when each of the plurality of images is captured. The method may include determining the longitudinal distance between the one or more images based on a predetermined spacing between the markers. The method may include determining an estimated longitudinal position for each of the plurality of images by interpolating the longitudinal distance.

[0018] In some embodiments, multiple marks are uniformly spaced at a uniform interval ranging from 1 cm to 5 cm (e.g., 1.5 cm, 2.5 cm, 3 cm, 4.5 cm, 5 cm, and any values ​​and ranges therewith). In some embodiments, multiple marks are uniformly spaced at a uniform interval ranging from 2 mm to 50 mm (e.g., 2.0 mm, 3.0 mm, 4.0 mm, 5.0 mm, 10.0 mm, 15.0 mm to 50.0 mm, and any values ​​and ranges therewith). In some embodiments, multiple marks are uniformly spaced at a uniform interval ranging from 2 mm to 50 mm (e.g., 2.0 mm, 3.0 mm, 4.0 mm, 5.0 mm, 10.0 mm, 15.0 mm, 20.0 mm, 25.0 mm, 30.0 mm, 40.0 mm, 50.0 mm, and any values ​​and ranges therewith). In various embodiments, one or more location inputs are (i) provided by a single verbal word from the user as they pass each anatomical point among multiple markers, (ii) a separate verbal word associated with the process of passing each anatomical point among multiple markers, (iii) involving pressing a button, (iv) involving tapping an IVUS catheter or catheter interface module, and / or (v) involving pressing a foot pedal. In some embodiments, the method includes providing visualization of multiple images with a distance-based longitudinal axis, measuring / reporting the longitudinal distance between two consecutive images of the multiple images, and / or measuring / reporting the distance between two or more images of the multiple images. In one embodiment, the complementary imaging modality is X-ray fluoroscopy, in which the progression (or advancement) of multiple markers is seen passing through anatomical points, and in which the direct progression of multiple markers is seen passing through an inlet sheath, guide catheter, or some other fixation point outside the body.

[0019] According to various embodiments, a method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter may include inserting the IVUS catheter into a patient. The IVUS catheter may include a catheter body, one or more ultrasound transducers disposed within the catheter body, and one or more markers disposed longitudinally along the catheter body. The method may include receiving one or more movement reporting inputs from a user and determining the length of the longitudinal movement based on the one or more movement reporting inputs via a processor, wherein the longitudinal movement is caused by manual movement of the catheter body. The one or more movement reporting inputs may include one or more of the following: voice input, mechanical input, touch input, or a combination thereof. In one embodiment, the movement reporting input provides unidirectional movement, longitudinal movement rate, and / or reference position, wherein the reference position corresponds to the anatomical position of the catheter body relative to the patient. The markers may be one or more strips disposed on an external surface or inserted within the catheter body, and may optionally be radiopaque. The method may detect error conditions such as incorrect marker order, duplicate markers, missing markers, or inconsistencies in the detection of one or more markers.

[0020] According to various embodiments, an intravascular ultrasound (IVUS) catheter system configured for detecting longitudinal position includes: a catheter body configured to be disposed within the lumen of a patient's blood vessel; one or more markers disposed along the catheter body; and a processor configured to: receive one or more motion reporting inputs from a user; determine longitudinal movement based on the one or more motion reporting inputs; and provide an output to the user based on the longitudinal movement. The one or more motion reporting inputs may include one or more of the following: voice input, mechanical input, touch input, or a combination thereof. The markers may include one or more strips disposed on an external surface of the catheter body or inserted within the catheter body, and the markers may optionally be radiopaque. The system can detect erroneous conditions such as incorrect marker order, duplicate markers, missing markers, or inconsistent detection of one or more markers.

[0021] According to various embodiments, a method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter may include manually moving the IVUS catheter along its longitudinal axis, wherein the IVUS catheter includes multiple markers along the length of its longitudinal axis, wherein the multiple markers are visible through complementary imaging modalities. The method may include: providing a user with multiple pacing outputs based on a preset (or programmed) movement rate; storing multiple images of the multiple markers relative to a series of anatomical points; and determining an estimated longitudinal position for each of the multiple images based on the preset movement rate. The method may also include (i) measuring / reporting the longitudinal distance between two consecutive images in the multiple images, (ii) measuring / reporting the distance between two or more images in the multiple images, (iii) prompting the user to accept or reject the estimated longitudinal position for each of the multiple images, and / or (iv) providing a visualization of the multiple images with distances based on the longitudinal axis. In various embodiments, the pacing outputs are auditory, tactile, and / or visual. In some embodiments, the multiple marks are uniformly spaced at a uniform interval of 1 cm to 5 cm (e.g., 1.5 cm, 2.5 cm, 3 cm, 4.5 cm, 5 cm, and any value and range therewith). In some embodiments, the multiple marks are uniformly spaced at a uniform interval of 2 mm to 50 mm (e.g., 2.0 mm, 3.0 mm, 4.0 mm, 5.0 mm, 10.0 mm, 15.0 mm to 50.0 mm, and any value and range therewith).

[0022] According to various embodiments, a method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter may include inserting or retracting the IVUS catheter into the patient. The IVUS catheter may include a catheter body, one or more ultrasound transducers disposed within the catheter body, and / or one or more markers disposed longitudinally along the catheter body. The method includes providing one or more pacing instructions to the user, and, based on the one or more pacing instructions, determining via a processor the length of longitudinal movement of the catheter body, wherein the longitudinal movement is caused by manual movement of the catheter body. The one or more pacing instructions may specify a rate of unidirectional movement by the user, and this rate may be in the range of 1 mm / sec to 20 mm / sec (e.g., 1 mm / sec, 2 mm / sec, 3 mm / sec, 4 mm / sec, 5 mm / sec, 6 mm / sec, 7 mm / sec, 8 mm / sec, 9 mm / sec, 10 mm / sec, 12 mm / sec, 14 mm / sec, 16 mm / sec, 18 mm / sec, 20 mm / sec, and any values ​​and ranges thereto). In some embodiments, the method includes receiving IVUS images from the user's reception rate, collecting IVUS images, and / or annotating IVUS images based on the longitudinal movement of the catheter body. In various embodiments, the pacing output is auditory, tactile, and / or visual.

[0023] According to various embodiments, an intravascular ultrasound (IVUS) catheter system configured for detecting longitudinal position includes: a catheter body configured to be disposed within the lumen of a patient's blood vessel; one or more markers disposed along the catheter body; and a processor configured to: provide one or more pacing commands to a user; determine the length of longitudinal movement based on the one or more pacing commands; and / or provide an output to the user based on the longitudinal movement.

[0024] Additionally, in several embodiments, the system and method do not require co-registration with another imaging technique such as angiography, manual movement of the IVUS catheter is achieved without the use of a linear actuation motor, and / or the IVUS catheter does not include a telescopic component.

[0025] In various embodiments, a method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter may include: manually moving the IVUS catheter along its longitudinal axis; capturing multiple images with the IVUS catheter while moving it along its longitudinal axis in a proximal or distal direction; measuring the distance traveled by the IVUS catheter using a device for encoding; correlating image or tissue features in the multiple images with the distance traveled by the IVUS catheter; and determining the longitudinal length between the images of the tissue features based on the distance measured by the device for encoding. The device for encoding may include, or substantially consist of, for example, an encoder not associated with a mechanical actuator or motor. In various embodiments, the device for encoding is mechanical, optical, inductive, and / or capacitive (or a combination thereof). In various embodiments, the encoder is disposable and smaller than existing non-disposable motorized pull-back units that require a sterile bag / cover before placement in a sterile field. The encoder unit can be attached to the inlet sheath or guide catheter at the entry point into the patient, so the encoder unit does not occupy much space in the sterile field. In other embodiments, the smaller encoder is not disposable and can be easily sterilized again by autoclaving for frequent reuse.

[0026] In various embodiments, an intravascular ultrasound (IVUS) catheter system configured for detecting longitudinal position includes: a catheter body configured to be disposed within the lumen of a patient's blood vessel; one or more markers disposed along the catheter body; and means for measuring the rate of movement of the one or more markers, for example, when the catheter body is moved longitudinally by hand; and the ability to measure / report one or more output lengths to a user based on manual movement of the catheter body. The means for measurement may include or substantially consist of an encoder, a position sensor, an alignment device, etc.

[0027] In several embodiments, the technologies described herein, including catheterization techniques, are used in conjunction with other medical imaging systems, such as cardiac catheterization laboratory systems, to provide cardiologists with an integrated suite of healthcare items. In several embodiments, an integrated or coordinated platform can improve workflows between various imaging systems, including, for example, x-ray systems. In one embodiment, the IVUS technologies described herein are used in conjunction with x-rays, external ultrasound, and / or other non-IVUS technologies to optimize stent placement and other procedures (e.g., thrombectomy, clot removal, balloon placement, etc.).

[0028] In several embodiments, the IVUS technology described herein is used in conjunction with other catheter-based 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, in vivo microscopy, 2D imaging, 3D imaging, etc. Several embodiments described herein utilize simultaneous operation, imaging, and / or measurement from two, three, or more imaging modalities, such as ultrasound, X-ray (including radiography, fluoroscopy, angiography, venography, etc.), magnetic resonance, PET scans, optical imaging (e.g., optical coherence tomography, optical imaging, laser imaging), etc. Several embodiments achieve multimodal synergy between IVUS and one or more additional imaging systems, including, for example, enhanced visualization and image quality, reduced procedure time, increased accuracy in stent placement and vascular measurement, improved workflow and reliability, and other benefits. For example, multimodal systems incorporating IVUS can be used to allow cardiologists to diagnose and / or treat vascular blockages and other defects, thereby providing patients with improved cardiac treatment outcomes while reducing the overall cost burden on healthcare systems through effective and efficient integration with IVUS. Using various embodiments of the IVUS technology described herein, more robust images of vascular and organ structures, such as cardiac structures, can be obtained.

[0029] In several embodiments, catheters optimized for vascular imaging are configured for excellent maneuverability, tracking, and traversal of peripheral vascular systems of arteries and veins. In several embodiments, one or more of the following features are provided: Maneuverability: In several embodiments, the catheter exhibits excellent maneuverability to avoid kinking and sufficient column strength to allow it to be advanced through tortuous bends and occlusions in the blood vessels without flexing, excessively bending, or collapsing anywhere along the catheter (e.g., approaching or (e.g., the ability to traverse occlusions or constrictions)). In some embodiments, material properties (e.g., a balance of rigidity and flexibility, stiffness of individual segments), and dimensional properties (e.g., larger dimensions, such as diameter and thickness) increase column strength, addressing greater maneuverability and resistance to kinking.

[0030] Tracking: In several embodiments, the catheter has excellent tracking capabilities because it can follow the guidewire through the twists and turns of the vascular system, possessing sufficient flexibility and strength to move and advance along the guidewire to a target location within the vascular system. A hydrophilic coating, according to some embodiments, helps reduce friction with the guidewire and surrounding luminal tissue. In various embodiments, the hydrophilic coating is on the outer and / or inner surfaces of the catheter (e.g., within the lumen, etc.). In some embodiments, the hydrophilic coating is not on the outer surface of the catheter. In some embodiments, the hydrophilic coating is not on the inner surface of the catheter (e.g., within the lumen, etc.).

[0031] Transverse: In several embodiments, the catheter has superior traversal capability to traverse occlusion, restriction, and constriction within the vascular system, such as at sites of tissue obstruction (e.g., stenosis, etc.) and / or implanted obstruction (e.g., stents, balloons, etc.). According to some embodiments, traversal capability is enhanced by one or more of the following: (i) the design of the distal tip (e.g., sufficiently sharp to navigate the occlusion, etc., and sufficiently blunt to not obstruct the occlusion), (ii) material properties (e.g., a balance of rigidity and flexibility, stiffness in individual segments, etc.), and / or (iii) dimensional properties (e.g., larger dimensions, such as diameter and thickness, increasing column strength). In one embodiment, low stiffness near the distal tip provides flexibility for navigation through tortuous anatomy and obstacles. In one embodiment, a region with varying or stepped gradients of stiffness is provided that changes proximally to be sufficient to move the catheter while avoiding kinking. Individual stiffness and / or flexibility may remain constant along specific portions or all portions of the device.

[0032] In various embodiments, a kit is provided that includes one, several, or all of the following catheters, components, encoders, connectors as described herein, and instructions for use.

[0033] In some embodiments, artificial intelligence and / or machine learning (AI / ML) are employed to enable and / or enhance measurement and / or image interpretation using the techniques described herein. In one embodiment, the system uses acoustic and signal processing tailored for peripheral vascular imaging with enhanced resolution and / or penetration to match high-resolution (e.g., HD, UHD, HD+, etc.) image quality. Several embodiments are configured for intravascular imaging with a platform optimized for peripheral and / or coronary vascular procedures, enabling improved image interpretation, interventional guidance, and enhanced ease of use and overall usability to streamline intraoperative and clinical workflows. In several embodiments, the system improves the usability of contemporary systems characterized by a simplified user interface and enhanced overall system capabilities leveraging AI to streamline workflows and image interpretation. In several embodiments, the system described herein includes, for example, an advanced intravascular ultrasound platform that leverages artificial intelligence (AI) to enable image interpretation, enhance overall system capabilities, and streamline workflows to maximize clinical value. In some embodiments, advantageously, physicians will not need to spatially and temporally integrate (e.g., cognitively integrate) imaging data to fully interpret clinical conditions. Conversely, systems according to several embodiments described herein can leverage the capabilities of generationally advanced AI to go beyond single-image interpretation. In several embodiments, for example, the AI-powered engine may comprise a workstation that enhances image interpretation through a streamlined workflow to improve overall usability. Machine learning is used in several embodiments. In one embodiment, AI-ready processing capabilities are designed to support real-time and on-demand image interpretation. The AI-powered workstation can provide high-end processing and artificial intelligence engines for advanced signal and image processing. In various embodiments, native image data capture provides superior image interpretation (e.g., boundary detection, identification and measurement of vessel size, vascular disease, dissection, plaque morphology, etc.). In several embodiments, the systems described herein provide simplified measurements via automatic boundary detection (e.g., AI algorithms automatically identify the boundaries of lumens, vessels, tissues, lesions, plaques, etc.). In several embodiments, the system provides simplified measurements via semi-automatic boundary detection (e.g., the user can manually adjust or modify the automatic AI algorithm for identifying the boundaries of lumens, vessels, tissues, lesions, plaques, etc., where boundary selection is reconfigured based on user modifications). In one embodiment, AI plaque recognition uses AI algorithms to automatically classify and identify plaque types within the imaging area to provide user guidance on treatment options (e.g., color coding, icons, or text overlays can be used to indicate what type of conditions, such as plaques, might be present in the selected image).In several embodiments, the data-driven platform is designed to collect data, streamline image interpretation, leverage AI processing capabilities to support real-time and on-demand image interpretation, and reduce user cognitive load to help (i) identify lumen size, (ii) visualize dissection, (iii) characterize disease morphology, (iv) locate and quantify stenosis, and / or (v) identify the actual lumen. In some embodiments, image interpretation is used to identify thrombi, thrombus formation, clots, embolisms, plaques, calcium, tissue health, stent or balloon attachment, and / or stent or balloon “health” or condition. Image interpretation may involve imaging to assess the quality and / or location of existing stent placement. Image interpretation may involve identifying location relative to the lumen wall and determining the level and / or quality of tissue growing within and around the stent or balloon. In one embodiment, for example, for a bioresorbable stent, image interpretation may involve (i) assessing the amount of stent dissolution and (ii) determining whether the stent dissolution conforms to the expected attenuation pattern (e.g., determining whether the attenuation level on one side of the stent is similar to that on the other side; if they are not similar, it may indicate a problem with stent placement, or if the stent dissolves faster than expected, it may indicate that the stent is not providing the expected structural support to the tissue). In one embodiment, high-fidelity ultrasound data is used to drive improved image generation and image interpretation, with options for leveraging artificial intelligence and / or machine learning. In various embodiments, catheters, devices, systems, and methods may be configured to perform edge-based machine learning computations associated with images and / or image analysis, using artificial intelligence algorithms to identify one or more of tissue boundaries, plaques, calcium deposits, thrombi, dissections, and / or stent attachments.

[0034] In various embodiments, the IVUS catheter is configured for imaging tissue and / or plaque (e.g., any one or more of hard plaques, soft plaques, vulnerable plaques, calcified plaques, and substantially non-calcified plaques) (alone or in combination with therapy). In various embodiments, the IVUS catheter is configured for imaging thrombi. In several embodiments, the techniques described herein are used for one or more of the following: thrombus identification, dissection, calcification severity, vascular measurement, and / or pre- and post-operative planning. In several embodiments, the techniques described herein are used to guide stent sizing, identify stent placement, attachment, and / or expansion, assess lesion morphology, vessel wall thickening, loss of luminal patency, and / or vascular dysfunction, quantify plaque burden, identify surgical complications, and / or assess stent failure due to stent thrombosis or in-stent restenosis. The techniques described herein can distinguish between lipids, calcified plaques, and tissue hyperplasia. In many embodiments, better imaging detail is provided than, for example, angiography.

[0035] As used in the overview above and the description below, in cases where a device or method “comprising” or “including” (the two are interchangeable) certain features or steps, such a device or method may also “consistently comprise…” of certain such features or steps, if so identified (i.e., “consistently comprise…” is stated in the claims).

[0036] The techniques described herein are used in several embodiments of encapsulated, sealed IVUS catheters with no flushing required to reduce air bubbles and eliminate the need for flushing acoustic coupling fluid, including those described in U.S. Patent Serial No. 63 / 459,312 entitled "Systems and Methods for No Flushing IVUS Catheters" and U.S. Patent Serial No. 63 / 546,091 entitled "Systems and Methods for No Flushing IVUS Catheters," as well as PCT / US2024 / 024045 filed April 11, 2020, which claims priority thereto. The techniques described herein are used in several embodiments for focusing intraluminal images using a rotating element ultrasonic transducer via image modification (e.g., angular diffraction, phase, amplitude, time shift, synthetic backscatter reflection image), including the techniques described in U.S. Patent Serial No. 63 / 497,962 entitled “Rotating Element Ultrasonic Transducer and Focusing Method” and PCT / US2024 / 024035 filed April 11, 2024, which claims priority thereto; as well as ultrasound imaging systems and components, voice control, and artificial intelligence algorithms, including the techniques described in U.S. Patent Serial No. 63 / 546,058 entitled “System and Method for Intravascular Ultrasound,” which are incorporated herein by reference in their entirety. Attached Figure Description

[0037] The following figures are for illustrative purposes only and illustrate non-limiting embodiments. Features from different figures may be combined in several embodiments.

[0038] Figure 1 This is a block diagram of a lateral sectional view of an intravascular ultrasound (IVUS) system according to an embodiment.

[0039] Figure 2A The diagram illustrates the polar plane of the polar coordinate system relative to the catheter body according to an embodiment.

[0040] Figure 2B The illustration shows an embodiment. Figure 2A The isometric view of the polar coordinate system shown in the figure.

[0041] Figure 2C A series of IVUS images and their strip images according to embodiments are depicted.

[0042] Figure 3This is a block diagram of a marked IVUS system according to an embodiment.

[0043] Figure 4A An example procedure for measuring longitudinal movement of an IVUS catheter system according to an embodiment is illustrated.

[0044] Figure 4B An example procedure for measuring longitudinal movement of an IVUS catheter system according to an embodiment is described.

[0045] Figure 5A An example procedure for measuring longitudinal movement of an IVUS catheter system according to an embodiment is described.

[0046] Figure 5B An example procedure for measuring longitudinal movement of an IVUS catheter system according to an embodiment is described.

[0047] Figure 6A It is an X-ray image showing the positioning of multiple markers relative to a reference point according to an embodiment.

[0048] Figure 6B It is an X-ray image showing the positioning of multiple markers relative to a reference point according to an embodiment.

[0049] Figure 6C It is an X-ray image showing the positioning of multiple markers relative to a reference point according to an embodiment.

[0050] Figure 6D It is an X-ray image showing the positioning of multiple markers relative to a reference point according to an embodiment.

[0051] Figure 7 This is a graph illustrating the hysteresis between translation at the insertion point of the catheter and translation at the catheter tip, according to an embodiment.

[0052] Figure 8 An embodiment of a relative insertion depth measuring device using a mechanical encoder is illustrated.

[0053] Figure 9A and Figure 9B An embodiment of a relative insertion depth measuring device using an inductive encoder is illustrated.

[0054] Figure 9C A schematic circuit diagram of an inductive encoder according to an embodiment is shown.

[0055] Figure 10 An embodiment of a relative insertion depth measuring device using an inductive encoder is illustrated.

[0056] Figure 11 An embodiment of a relative insertion depth measuring device using an optical encoder is illustrated.

[0057] Figure 12 An embodiment of a relative insertion depth measuring device using a mechanical wheel encoder is illustrated. Detailed Implementation

[0058] This document describes several embodiments for efficient and effective execution without relying on automated co-registration with another imaging platform, such as X-ray fluoroscopy or angiography. Several embodiments allow for shorter procedure times, reduced contrast agent use, precise control, and the measurement of the flexibility of intracavitary tissues (e.g., lesions, calcifications, etc.) without the need for co-registration. While automated co-registration remains feasible for the embodiments described herein, eliminating any necessary dependence on automated co-registration is particularly advantageous in several embodiments.

[0059] According to several embodiments, the systems and methods described herein are aimed at improved intravascular ultrasound imaging and measurement. In several embodiments, the systems and methods use manual translation of the catheter to provide vascular-oriented distance measurements for recording sequential intravascular IVUS images in humans. IVUS recording performed during catheter withdrawal within the vessel is a workflow referred to as “pullback.” In various embodiments, references to “pullback” movement of the catheter can refer to retracting the catheter in a proximal direction, and also consider advancing the catheter in a distal direction within the vessel. Longitudinal movement includes pulling or retracting the catheter from the vessel or other lumen, pushing or otherwise advancing the catheter into the vessel or other lumen, or both. Enhancing pullback with distance measurement information effectively increases clinical value and workflow by facilitating length measurements between images during pullback. In several embodiments, IVUS imaging is used to diagnose unhealthy vascular systems and guide and evaluate treatments. In various embodiments, IVUS may be used for imaging only. In various embodiments, IVUS may be used for treatment only. In various embodiments, IVUS is used for imaging and therapy, including therapies such as heating, coagulation, ablation, ultrasound HIFU, drug delivery, anticoagulants (such as heparin, warfarin, dabigatran, apixaban, and / or rivaroxaban), biologics, thrombolytics, microbubbles, and / or interventional therapies. In one embodiment, an IVUS system includes a disposable catheter for deploying an ultrasound image acquisition unit within a vascular system and an accompanying imaging system or console. In one embodiment, a processor detects the longitudinal movement of the catheter. The processor may use an output device to specify the longitudinal movement speed to the user and / or use an input device to receive the longitudinal movement speed from the user to determine the longitudinal position of the catheter. In some embodiments, the processor may correlate IVUS images with the longitudinal position of the catheter at the time the IVUS images are captured. For example, the processor may annotate IVUS images to include the longitudinal position. The longitudinal position may be defined relative to an anatomical point of interest.

[0060] Advantageously, according to several embodiments, these systems and methods provide excellent manual control over catheter positioning while determining an accurate estimate of the longitudinal position of the catheter. User manipulation of the IVUS catheter allows for longitudinal measurement and imaging relative to a point or location of interest rather than relative to a point in time. According to various embodiments, the measurement and imaging of relative position can allow for 3D rendering of multiple IVUS images. In some cases, the system and methods may employ automated lumen or vessel wall detection and / or 3D vessel modeling. The system and methods provide enhanced imaging quality and efficiency by correlating images with points of interest, which can improve the speed and accuracy of delivery of one or more therapies, such as stents. In some embodiments, the system and methods provide automatic annotation of IVUS images with longitudinal position information, such as the location, speed, or length of longitudinal movement. The embodiments described herein eliminate the guesswork associated with manually advancing and withdrawing and / or retracting the IVUS catheter. In turn, physicians can provide more accurate diagnoses and treatments to patients to improve patient outcomes.

[0061] Figure 1The illustration shows an intravascular ultrasound (IVUS) system 100 according to one embodiment. The intravascular ultrasound system 100 includes a catheter body 102. The catheter body 102 is a flexible, elongated member. The catheter body 102 may be of a fixed length. In some embodiments, the IVUS catheter has a length configured for connection to an external catheter interface module of a sterile field. In various embodiments, the length of the catheter body 102 may be at least 90 cm, at least 120 cm, at least 150 cm, at least 180 cm, at least 210 cm, at least 240 cm, at least 270 cm, at least 300 cm, at least 330 cm, or at least 360 cm (e.g., lengths of 90 cm, 100 cm, 105 cm, 110 cm, 120 cm, 125 cm, 135 cm, 140 cm, 150 cm, 160 cm, 175 cm, 190 cm, 200 cm, 210 cm, 230 cm, 250 cm, 280 cm, 310 cm, 350 cm, 370 cm, or 400 cm, or values ​​therein). For example, the length of the catheter body 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 some embodiments, the catheter body 102 may not include any telescopic members. The catheter body 102 may consist of one, two, or more housings, lumens, coils, media, connectors, sensors, and / or measuring devices. In some embodiments, the catheter body 102 may include one, two, or more layers of material to refract ultrasonic signals and / or limit backscattered signals in a desired manner. In one embodiment, one, two, or more layers of material may be shaped to refract ultrasonic signals and / or limit backscattered signals in a desired manner, such as with a lens. The catheter body 102 has a proximal end and a distal end.

[0062] In various embodiments, the imaging core 104 includes a transducer, which may be a single-element transducer or an array of multi-element transducers. In one embodiment, a single ultrasound transducer (e.g., having only a single element, without multiple elements, without a plurality of elements, and / or without an element array) is positioned at an intravascular location with a catheter for acoustic imaging. In various embodiments, the multi-element array may be an array of 2, 8, 10, 12, 16, 24, 32, 50, 64, 100, or 128 elements. In one embodiment, the transducer is rotated by an actuator, while one, two, or more receiving transducers may remain stationary. The catheter body 102 has a flexible wall extending along the length of the catheter from a proximal end to a distal end. The catheter body 102 also includes one or more lumens, such as a lumen. In one embodiment, the lumen may extend from the proximal end of the catheter body 102 to a distal end. In one embodiment, the lumen may extend from the proximal end of the catheter body 102 to a distal portion. The lumen may be defined by the wall of the catheter body 102. In one embodiment, the wall of the catheter body is flexible. According to some embodiments, the lumen may be defined by the wall of a member inserted into the catheter body 102. In some embodiments, the catheter body 102 may include two or more lumens. The lumens may be sealable and include a proximal port and a distal port.

[0063] In several embodiments, system 100 includes an imaging core 104 having a rotating transducer 105. In various embodiments, the rotating transducer 105 is a component of the imaging core 104. The rotating transducer 105 may be located at a distal end of the catheter body 102 and generate a plurality of ultrasound signals 106. In some embodiments, the rotating transducer 105 may be oriented such that the ultrasound signals propagate perpendicular to the catheter body 102. In some embodiments, the rotating transducer 105 may be oriented such that the ultrasound signals propagate in a circular shape perpendicular to the catheter body 102. In several embodiments, the ultrasound signals propagate away from a direction perpendicular to the catheter body wall, forming a conical shape relative to the catheter wall. The rotating transducer 105 may be oriented such that the ultrasound signals propagate perpendicular to an axis. The device may include an imaging core 104, which includes a rotating ultrasound transducer connected to a distal end of a drive shaft. A device may include a flexible elongated member comprising a sealed cavity configured to receive an ultrasound imaging core 104 and an acoustic coupling medium, wherein the sealed cavity includes a proximal end, a distal end, and a flexible wall extending a length between the proximal and distal ends. The device is configured for connection to a control console configured to actuate a drive shaft via a lumen of the catheter body 102. A rotary transducer 105 may also detect multiple backscattered signals. In some embodiments, the system 100 may include one, two, or more generating transducers and one, two, or more receiving transducers.

[0064] In one embodiment, the lumen is configured to receive a rotary transducer 105 and a drive shaft 110. The drive shaft 110 mechanically couples the rotary transducer 105 to a rotary actuator 114. The lumen may be configured to receive a coupling medium. In various embodiments, system 100 includes actuator 114. Actuator 114 may include components or systems configured to cause relative movement between two or more components (e.g., rotational and / or translational movement, rotational movement without translational movement, and / or translational movement without rotation) (e.g., movement between rotary transducer 105 and conduit body 102). Actuator 114 may include, for example, one, two, or more, or a combination of hubs, seals, valves, adhesives, bearings, hinges, pins, balls and pinions, shafts, rotary joints, clutches, discs, gears, belts, motors, linear sliders, linear actuators, tracks, grooves, slots, cams, vibration tables, etc. In several embodiments, the actuator is not necessarily associated with electronic, motorized, or other automated systems, and embodiments of one or more actuators described herein can be configured to move manually, semi-automatically, and / or automatically. For example, actuator 114 may be a drivetrain or drive shaft. Actuator 114 may rotate a rotary transducer 105 within the duct body 102 in the azimuth direction.

[0065] In one embodiment, the image is formed by multiple radial ultrasound lines approximately aligned with a two-dimensional (2D) grid in polar coordinate space orthogonal to the catheter length axis. In this way, a ring-shaped image representing a slice of anatomical information at the longitudinal position of the acquisition unit is presented to the user. Figure 2A and Figure 2B The figure illustrates such an annular image region with polar coordinate markings and its orientation relative to the catheter body 102 at the acquisition unit location.

[0066] Figure 2A The diagram illustrates the polar plane 202 of the polar coordinate system 200 relative to the catheter body 102. As described above, in some embodiments, the imaging field of the IVUS catheter can be defined as a polar coordinate system 200 centered on one or more transducers 204. As used herein, the azimuth angle can refer to the angle 206 between the imaging line 208 and the vertical axis 210 extending from the center (in... Figure 2A The terminator is denoted by the angle "p". The radius can refer to the distance from the center, i.e., the distance or depth from one or more transducers. As used herein, axial or longitudinal can refer to the axis perpendicular to the polar coordinate plane and multiple imaging lines, corresponding to the movement of the catheter in the proximal / distal direction.

[0067] Figure 2B The diagram shows... Figure 2A The isometric view of the polar coordinate system shown in the figure. Figure 2B As shown, the polar plane 202 may correspond to a longitudinal position along the catheter body 102 and / or the catheter path.

[0068] In various embodiments, the image can be formed by rotating unit elements or by an array of multiple elements. During real-time imaging, the acquisition process is performed at imaging frequencies (e.g., within the range of 1–90 MHz, such as 1 MHz to 10 MHz, 10 MHz to 15 MHz, 10 MHz to 20 MHz, 10 MHz to 25 MHz, 10 MHz to 30 MHz, 10 MHz to 40 MHz, 15 MHz to 30 MHz, 15 MHz to 35 MHz, 15 MHz to 40 MHz, 15 MHz to 50 MHz, 15 MHz to 60 MHz, 15 MHz to 70 MHz, 20 MHz to 30 MHz, 30 MHz to 40 MHz, 40 MHz to 50 MHz, 20 MHz to 25 MHz, 20 MHz to 30 MHz, 20 MHz to 40 MHz, 20 MHz to 45 MHz, 20 MHz to 50 MHz, 25 MHz to 35 MHz, 25 MHz to 40 MHz, 25 MHz to 45 MHz). Repeat the range of MHz, 25 MHz to 50 MHz, 30 MHz to 45 MHz, 30 MHz to 50 MHz, 40 MHz to 45 MHz, 45 MHz to 50 MHz, 50 MHz to 60 MHz, 50 MHz to 70 MHz, 50 MHz to 80 MHz, 55 MHz to 75 MHz, 55 MHz to 65 MHz, 60 MHz to 70 MHz, 60 MHz to 90 MHz, 70 MHz to 80 MHz, 70 MHz to 90 MHz, and any values ​​and ranges thereof. In one embodiment, real-time imaging is repeatedly acquired at a frame rate to provide a real-time 2D imaging modality (e.g., frame rates in the range of 12 Hz to 120 Hz, e.g., 12 Hz, 15 Hz, 20 Hz, 25 Hz, 30 Hz, 35 Hz, 40 Hz, 45 Hz, 50 Hz, 55 Hz, 60 Hz, 65 Hz, 70 Hz, 75 Hz, 80 Hz, 90 Hz, 100 Hz, 110 Hz, 120 Hz). The pull-back recording of continuously acquired IVUS images during catheter withdrawal within the vessel can be used to measure tissue length along the vessel. In one embodiment, stacking 2D images recorded during pull-back can construct a data volume. In one embodiment, by stacking selected diameters from each of the annular images, an alternative 2D image referred to as a “strip” image can be formed. In one embodiment, the stacking of data from images acquired during pull-back constitutes a spatial sampling of the longitudinal dimension out of plane relative to a single IVUS image. exist Figure 2CThe illustration shows an example of a drawing that associates these image types with a series of stacked images from the pullback. In one embodiment, such stacked images may not be formed, but an understanding of the longitudinal separation of individual images is still available and advantageous. In several embodiments, strip images may be created as the catheter is advanced in the distal direction.

[0069] Figure 2C A strip image 250 comprising multiple IVUS images 240 is depicted according to one embodiment. The IVUS images 240 may be grouped or subsetd based on longitudinal position. Groups of IVUS images 240 may be stacked longitudinally to produce the strip image 250. The strip image 250 may be a two-dimensional IVUS image combining the IVUS images 240 in a longitudinal plane. For example, IVUS images 240 captured between the proximal and distal ends of a calcified lesion may be combined to form the strip image 250. In some embodiments, the catheter system may automatically generate strip images for pullback recording. The processor 112 may automatically generate strip images based on time intervals of the individual images, where the stacking of images is a time-axis-oriented strip image. When the relative longitudinal position of an individual image is known or estimated, such as via the embodiments described herein, the individual images may be stacked relative to a distance axis representing the nominal longitudinal position or process of the distal end of the catheter in the lumen. In some embodiments, processor 112 may create a strip image aligned with the distance axis using a relationship between recording time and distance position based on user input indicative of the longitudinal progression of the catheter during recording. In some embodiments, processor 112 may use a relationship between recording time and distance position achieved through adjustments to the user's movements during pullback to create a strip image aligned with the distance axis. In some embodiments, processor 112 may use a relationship between recording time and distance position obtained from a small encoder at the point where the catheter is inserted into the body to create a strip image aligned with the distance axis.

[0070] In several embodiments, images can be uniformly stacked without distance information. For standard manual pullback, no distance information is known, so the out-of-plane dimensions of the strip images only represent the time or number of frames during recording. For automated mechanical sleds, movement (e.g., pullback or advance) progresses (or travels) at a uniform rate, and longitudinal progress is proportional to recording time (e.g., progress equals speed multiplied by time), so images can be uniformly stacked relative to the longitudinal axis on a distance scale of, for example, millimeters. In several embodiments, a system for estimating location based on recording time is provided herein. In one embodiment, progress as a function of recording time is known, so strip images with a distance scale can be created even if the relationship is not a simple proportional one. In one embodiment, this information is advantageous regardless of whether a strip image is formed. For example, because blood vessels are tortuous, the true location of the images by pullback is not necessarily a perfect vertical stack. For example, regardless of whether a strip image is shown, the longitudinal interval between recorded images proximal and distal to the lesion represents the lesion length.

[0071] In one embodiment, longitudinal movement of the IVUS catheter is manually performed to produce IVUS images that are stacked to form volumetric or strip images in which the longitudinal dimension corresponds to the recording time. In one embodiment, length measurements between frames cannot be performed in this case. In one embodiment, the IVUS device provides measurements while retracting the IVUS catheter to a fixed, externally known position relative to the outside of the catheter. Adding longitudinal position information to the movement recording allows frames to be stacked in distance and length measurements can be performed between structures visualized at different times during longitudinal movement. In one embodiment, longitudinal measurement capability is achieved using user input based on markings on the catheter body observed by the user when the catheter is moved into the patient at the insertion point (e.g., at the inserter sheath, guide catheter, incision point, etc.). In one embodiment, longitudinal measurement capability is achieved using synchronized alignment measurements of IVUS image data with another imaging modality such as X-ray fluoroscopy.

[0072] In one embodiment, manual pull-back or advance without automated longitudinal positioning information produces IVUS images for surgical guidance, such as stent placement (e.g., determining where a stent in a vessel will begin and end). For example, the start and end points can be determined via IVUS imaging while these positions of the IVUS catheter are manually recorded during fluoroscopy (or other imaging modalities). The length between these points can then be estimated based on the tracking of the fluoroscopy images. Alternatively, the length between these points can be estimated based on the spacing of one or more radiopaque (RO) markers on the IVUS catheter. In various embodiments, manual pull-back or advance systems and methods enhance the use of manual longitudinal position estimation to streamline workflows and provide improved visualization of movement data in volumetric or strip displays. In various embodiments, this is achieved through efficient clinical workflows without requiring a motorized automated pull-back device or telescopic catheter design connected to a sterile patient environment.

[0073] In some embodiments, one or more markers 302 are spaced apart along a portion of the length of the catheter body 102. Figure 3 This is a block diagram of a side view of a rotating IVUS system 100 having one or more markers 302. In various embodiments, 1 to 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 thereof) are distributed along the catheter body 102. In some embodiments, the markers 302 are evenly spaced longitudinally along the catheter body 102. For example, the markings 302 can be spaced from 0.5 cm to 6.0 cm (e.g., 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1.0 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.5 cm, 1.8 cm, 2.0 cm, 2.3 cm, 2.5 cm, 2.7 cm, 3.0 cm, 3.3 cm, 3.5 cm, 3.7 cm, 3.8 cm, 3.9 cm, 4.0 cm, 4.1 cm, 4.2 cm, 4.4 cm, 4.5 cm, 4.8 cm, 5.0 cm, 5.3 cm, 5.5 cm, 5.8 cm, 6.0 cm, and any values ​​and ranges therewith). In one embodiment, the markings 302 are radiopaque (RO).

[0074] In various embodiments, a mark 302 is disposed on the outer surface of the catheter body 102. The mark 302 may be a printed or forged ring disposed on or embedded in the outer surface of the catheter body 102. Alternatively, the mark may be inserted into an internal component within the catheter body, such as another tubular component having a forged or fused RO ring. In one embodiment, the mark 302 is a radiopaque ring member disposed within or on the catheter body 102. In some embodiments, the mark 302 may be a primary mark or a secondary mark. The primary mark may indicate a longitudinal distance, such as 2 cm to 10 cm (e.g., 2 cm, 3 cm, 5 cm, 7 cm, 8 cm, 10 cm, and any values ​​and ranges thereof), while secondary marks may be disposed between primary marks and positioned at a specific fraction of the distance between the two primary marks. In some embodiments, the mark 302 may be a primary mark or a secondary mark. The primary markers may indicate longitudinal distances, such as 20.5 cm to 10 cm (e.g., 0.5 cm, 1 cm, 2 cm, 3 cm, 5 cm, 7 cm, 8 cm, 10 cm, and any values ​​and ranges thereof), while secondary markers may be positioned between the primary markers and located at specific fractions of the distance between the two primary markers. For example, secondary markers may be positioned at every 1 / 10, 1 / 5, 1 / 4, or 1 / 3 of the longitudinal distance between the two primary markers. In some embodiments, the primary and secondary markers have different longitudinal lengths, such that the primary markers can be distinguished from secondary markers in images such as X-ray images (e.g., radiographic, fluoroscopic, and / or angiographic images).

[0075] In one embodiment, a series of manually moved IVUS images is captured as the catheter is manually translated along the vessel length. The longitudinal position of the images within the series is estimated through user / system interaction. This interaction utilizes visible bands or markers on the IVUS catheter indicating longitudinal translation over one or more surrounding anatomical references. For example, the translation of the catheter can be determined by movement via radiopaque (RO) markers over a bone reference visible in fluoroscopy, or by visible catheter markers over the body entry point. In one embodiment, the interaction is system-to-operator type, such as using an audible adjustment click to adjust the operator's catheter movement. In another embodiment, the interaction is operator-to-system type, such as a waypoint indicator given by the operator to the system via voice input. By correlating the capture time with the physical catheter translation, the image series can be presented relative to the length axis in the longitudinal direction of movement (e.g., in the case of "strip" images). In one embodiment, the image series is rendered relative to the longitudinal position and vessel length, for example, by distances between images that may correspond to desired stent start and end positions within the series, obtained and recorded via the IVUS system user interface. The longitudinal distance between anatomical points of interest can be obtained, and IVUS images can be used to assist in clinical treatment decisions, such as selecting balloon length and expandable stent length for percutaneous endovascular angioplasty. In one embodiment, such longitudinal distances between images in a series are obtained regardless of whether the image series has already been rendered relative to its longitudinal position.

[0076] In some embodiments, the IVUS catheter system may include an output device 304 to, for example, assist the user in receiving adjustment and / or measurement information. The output device 304 may be an audio output device, a tactile output device, a display device, or a combination thereof. An audio output device may be one or more speakers, headphones, or earpieces configured to emit sounds, tones, clicks, words, or phrases. A tactile output device is configured to apply force to the user, generate vibrations, generate movement, or a combination thereof. For example, vibrations, visual cues, and / or sounds on a watch or other display device may be used to signal catheter movement or other measurements within the blood vessel. The display device may be any device suitable for providing visual, auditory, tactile, or other outputs, such as a television, monitor, mobile device, tablet computer, smartwatch, projection screen, goggle display, eyepiece, etc.

[0077] Output device 304 can provide output from the system, such as notifications, instructions, commands, and / or feedback to the operator / user. In some embodiments, processor 112 can generate output and instruct output device 304 to provide that output to the user. As discussed in more detail below, processor 112 can instruct output device to provide pacing commands or pacing notifications to the user. For example, at the instruction of processor 112, output device 304 can provide audio commands or notifications in response to longitudinal movement of the conduit body 102.

[0078] In some embodiments, the IVUS conduit system may include an input device 306 for operator / user communication with the system. The input device 306 may include one or more of a microphone, a haptic input device, etc. The haptic input device may be a keyboard, buttons, switches, pedals, etc. The input device 306 may receive input from the user, such as voice input. In some embodiments, the processor 112 may be positioned to communicate electronically with the input device 306 and configured to receive input from the input device 306. For example, as discussed below, the processor 112 may receive pacing input from the user via the input device 306.

[0079] According to some embodiments, the catheter system 100 may not include a motorized pull-back device. Instead, the catheter body 102 can be manually moved in the longitudinal direction by a user, such as a physician.

[0080] In various embodiments, system-to-operator interaction involves the processor outputting information to the user. Figure 4A A system-to-operator interaction process 320 for detecting manual longitudinal movement of an IVUS catheter, according to one embodiment, is described. The system-to-operator interaction process 320 may be executed by a processor, such as processor 112. As discussed above, processor 112 may control components of the intravascular ultrasound catheter system, such as output device 304 for communication with the user and input device 306 for communication between the user and the system. Figure 4A The process 320 shown is an example system-to-operator interaction process. In some embodiments, process 320 may include more or fewer steps. In some embodiments, one or more steps of process 320 may be performed in a different order, or simultaneously with one or more other steps of process 320.

[0081] According to one embodiment, when an IVUS procedure begins acquiring IVUS images, a system-to-operator interaction process 320 may commence at step 322. In some embodiments, an IVUS procedure may begin when an IVUS catheter is inserted into the patient. The IVUS catheter may be inserted and manually advanced into (or retracted from) a blood vessel. For example, the surgeon performing the procedure may insert the IVUS catheter into the patient's femoral artery and manually advance the catheter through the patient's vascular system.

[0082] The system-to-operator interaction process 320 can move to step 324, where the processor 112 outputs information to the user regarding the longitudinal movement of the catheter. In some embodiments, the processor 112 may receive an indication from the user that the system has begun providing output information.

[0083] Processor 112 can provide pacing instructions to the user via an output device, such as output device 304. The output device can be an audio output device, a haptic output device, a display device, or a combination thereof. The pacing instructions can include multiple evenly spaced outputs indicative of a recommended speed for the conduit.

[0084] As discussed above, the catheter body may contain one or more markings, such as marking 302. These markings may be evenly spaced along the longitudinal direction of the catheter body. The one or more markings may be radiopaque.

[0085] The system-to-operator interaction output can contain multiple pacing instructions from the process to the user, instructing the user to move the catheter at a speed such that successive markers of one or more markers are aligned with the starting anatomical point. For example, the system can play a series of sounds, such as beeps, as pacing outputs for the user to hear. The beeps can be played at a steady rhythm to indicate to the user the recommended longitudinal movement speed of the processor. At the first beep, the first marker of one or more markers should be aligned with the starting point. In some embodiments, X-ray images of a portion of the patient are taken (e.g., radiographic examination, fluoroscopy, angiography), and the position of one or more radiopaque markers relative to the starting point can be assessed. At the second beep, the user can move the catheter in a proximal or distal direction via the pacing output provided by the system to indicate that the second marker of one or more markers should be aligned with the starting point. This sequence can continue such that successive markers of one or more markers are aligned with the starting point at each subsequent beep; for example, the third marker may be aligned at the third beep, the fourth marker at the fourth beep, and so on.

[0086] In some embodiments, the rate at which one or more markers are aligned with the starting point may correspond to a recommended longitudinal movement speed of the catheter. In some embodiments, the recommended longitudinal movement speed may be from 0.5 to 20 mm / s, for example, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 mm / s, and values ​​and ranges thereof. The recommended longitudinal speed may be a pre-set value. In some embodiments, the processor 112 may prompt the user to input the recommended longitudinal speed and receive the longitudinal speed from the user, and may provide auditory feedback, such as an alarm, and / or a request to accelerate or decelerate. In some embodiments, the processor 112 may receive another indication from the user of an end-of-movement command. Similarly, an indication of the end-of-movement direction may be received from the input device 306.

[0087] In some embodiments, process 320 may move to step 326, where processor 112 may detect or measure the length of longitudinal movement. Processor 112 may detect the length of movement based on the number of outputs provided by processor 112. The number of outputs may correspond to the number of marker lengths of movement in the proximal / distal direction. For example, processor 112 may provide four outputs, which may be provided to the user during the system's output of adjustment information to the user, and these four outputs may correspond to three marker distances representing a known distance of movement of the catheter in the proximal / distal direction. These four markers may be spaced 1 cm apart. Therefore, processor 112 may determine that the proximal / distal movement is 3 cm.

[0088] Process 320 can proceed to step 328, where processor 112 can provide an output to the user. Processor 112 can provide the output based on the length of longitudinal movement. This output can indicate the distance or speed of the conduit movement.

[0089] In some embodiments, the system-to-operator interaction output may include annotated IVUS images. During catheter body movement, the IVUS catheter system may capture one or more IVUS images. Processor 112 may calculate the catheter body movement and annotate the IVUS images to indicate the longitudinal position of the catheter. The longitudinal position may be the position of the distal end of the catheter relative to the insertion point or the initial dissection point. In some embodiments, processor 112 may annotate the IVUS images to include the corresponding longitudinal position of the catheter at the time the image was captured. Annotations may be provided in real-time or added retrospectively. According to some embodiments, processor 112 may annotate the IVUS images to include the catheter's velocity.

[0090] According to some embodiments, IVUS images can be grouped or subsetd based on their longitudinal position. Groups of IVUS images can be stacked longitudinally to produce striped images. Striped images can be two-dimensional IVUS images combining IVUS images in the longitudinal plane, such as... Figure 2C As shown in the diagram. For example, IVUS images captured between the proximal and distal ends of a calcified lesion can be combined to form a strip image. In some embodiments, the catheter system can automatically generate strip images. The processor 112 can automatically generate strip images based on the longitudinal position of the distal end of the catheter. In some embodiments, the processor 112 can create strip images based on user input, such as an instruction to start movement. In some embodiments, the processor 112 can calculate the length of the strip image and provide that length to the user.

[0091] In some embodiments, processor 112 can detect error conditions during the procedure. Processor 112 can generate output indicating error conditions. Error conditions can be detected when markers are not detected, are repeated, or are detected in an out-of-order manner. An error condition may exist if markers are detected in a sufficiently uneven manner. In some embodiments, when an error condition exists, processor 112 can reject the longitudinal movement length, longitudinal movement speed, and / or longitudinal position of the catheter. In the event of such an error, the system can retain the recorded images and revert to a recording without longitudinal length measurement capability. Processor 112 can provide the error condition to the user via the output. In some embodiments, the output may include IVUS images associated with the error condition, the rejected longitudinal movement length, the rejected longitudinal movement speed, and / or the rejected longitudinal position of the catheter, and the error condition.

[0092] Although process 320 is described as detecting manual longitudinal movement of the catheter via system-to-operator interaction, process 320 can be implemented using an automated longitudinal actuator. An automated longitudinal actuator can cause longitudinal movement of the catheter relative to the patient's blood vessel. In some embodiments, process 320 may also employ a mechanical pull-back skid, co-registration, or encoder-measured translation. In one embodiment, no motor and / or co-registration is used. In one embodiment, no encoder is used. In one embodiment, no actuator rod, knob, or tool is used.

[0093] Figure 4BA system-to-operator interaction process 400 for detecting manual longitudinal movement of an IVUS catheter according to one embodiment is illustrated. In some embodiments, process 400 may include more or fewer steps. In some embodiments, one or more steps of process 400 may be performed in a different order, or simultaneously with one or more other steps of process 400. In the system-to-operator interaction embodiment, the operator performing the longitudinal movement can adjust the speed using a series of indicators from the system representing the expected uniform progress of observable markers on the catheter past a fixed point. In the system-to-operator embodiment, system guidance can be considered analogous to how a metronome guides a musician to play music by guiding the longitudinal speed. The target longitudinal movement rate is preset in the system (or selected from pre-configured values), for example, 1 mm / sec to 20 mm / sec (e.g., 1 mm / sec, 2 mm / sec, 5 mm / sec, 10 mm / sec, 12 mm / sec, 15 mm / sec, 20 mm / sec, and values ​​and ranges therewith), and the system provides a pacing indicator as the operator performs the movement (e.g., pull back or push forward) so that the operator can adjust the translational rate and determine that the expected rate has been achieved. In this embodiment, the mapping between image capture time and longitudinal position can be aligned and / or synchronized according to the expected translation rate. In one embodiment, the user can reject spatial alignment or synchronization and retry the process.

[0094] The system-to-operator interaction process 400 can begin at step 402, where the IVUS catheter system processor, such as processor 112, can begin recording a series of images. Next, process 400 can move to step 404, where processor 112 can pace (or adjust) the catheter by outputting a pace progression per unit distance traveled via system pulses. Similar to steps 324, 326, and 328 described above, processor 112 can output longitudinal movement of the catheter to the user using one or more pacing commands. In various embodiments, processor 112 can provide pacing commands to the user via an output device. For example, processor 112 can generate a series of vibrations specifying a recommended longitudinal speed to the user via a haptic output device. In another example, processor 112 can generate a series of beeps or chimes specifying a recommended longitudinal speed to the user via a set of speakers. Processor 112 can determine the longitudinal position of the catheter based on multiple pacing commands provided during the movement command. In some embodiments, processor 112 may associate one or more IVUS images with the longitudinal position of the catheter at the time the IVUS images were captured. For example, processor 112 may annotate the IVUS images to include the longitudinal position.

[0095] Process 400 can proceed to step 406, where IVUS image recording ends. In some embodiments, the IVUS catheter system may receive input from the user to stop recording IVUS images. Next, process 400 can proceed to step 408, where the processor may prompt the user to accept or reject longitudinal position data. As discussed above, processor 112 may provide the user with annotated IVUS images as output. Processor 112 may also provide a user interface, such as a software interface, that allows the user to review the annotated IVUS images and accept or reject the annotated longitudinal position data. In one embodiment, the review process may include a dialog box to present the recorded travel information as annotations of the distance traveled, such as on a strip image or timeline with or without key images associated with a command. The images may be shown as thumbnails with a dialog box asking the operator whether the waypoint data is correct and explaining that the longitudinal distance between a series of images will be interpolated based on this data.

[0096] In various embodiments, operator-to-system interaction involves the user inputting information into the system. Figure 5A An operator-to-system interaction process 500 for detecting manual longitudinal movement of an IVUS catheter, according to one embodiment, is depicted. In some embodiments, the operator-to-system interaction process 500 may include more or fewer steps. In some embodiments, one or more steps of process 500 may be performed in a different order, or simultaneously with one or more other steps of process 500.

[0097] In various embodiments, input can be received via a user interface and / or via input device 306. For example, a user can provide a keyboard, mouse, touchscreen, or other input to initiate a movement command. In some embodiments, the indication can be voice input, which the processor 112 can receive via input device 306. In some embodiments, the indication to initiate a movement command can include anatomical points, which can be starting points or reference points. Anatomical points can include anatomical structures, such as anastomoses, points relative to radiopaque structures, proximal ends of calcified lesions, distal ends of calcified lesions, etc., as described below. Figure 5A and Figure 5B As discussed, users can specify or input one or more anatomical points to the IVUS catheter system.

[0098] According to one embodiment, the operator-to-system interaction process 500 may begin at step 502, where the IVUS procedure begins. Similar to step 322, the IVUS procedure may begin when the IVUS catheter begins collecting IVUS images. In some embodiments, the IVUS procedure may begin when the IVUS catheter is inserted into the patient. The IVUS catheter may be inserted and manually advanced into (or retracted from) a blood vessel. For example, the surgeon performing the procedure may insert the IVUS catheter into the patient's femoral artery and manually advance the catheter through the patient's vascular system.

[0099] The operator-to-system interaction process 500 can move to step 504, where the processor 112 can receive user input. The conduit system may include an input device. The input device may be a microphone, a haptic input device, or a camera. The processor 112 may receive input from the user via the input device, such as voice input. In some embodiments, the input may be words or sounds indicating longitudinal movement speed. For example, the input device may be a microphone. The user may provide input indicating longitudinal speed, and the processor 112 may receive this information and calculate the longitudinal speed.

[0100] In some embodiments, user input can provide reference point input. Reference point input can be associated with the current longitudinal position of an anatomical point relative to an anatomical point such as a radiopaque structure, the proximal end of a calcified lesion, the distal end of a calcified lesion, or any point where the catheter can be positioned. For example, the input device can be a microphone, and the physician can provide marker input indicating that a first marker of one or more markers is aligned with an anatomical point (such as a skeletal reference). Simultaneously, the distal end of the catheter can be positioned at the distal end of the calcified lesion. For example, the physician can say "a," and the processor 112 can receive voice input via input device 306.

[0101] The user can begin moving the catheter in a proximal / distal direction. According to some embodiments, the user can provide one or more pacing inputs indicating that a subsequent marker is located at a reference point, and the processor 112 can receive one or more pacing inputs. The one or more pacing inputs can be input via input device 306 and can be touch input, voice input, mechanical input, etc. Based on the pacing inputs, the processor 112 can calculate the longitudinal movement distance based on the known distance between the one or more pacing inputs and the one or more markers.

[0102] Returning to the example above, after providing a reference point, the user (e.g., operator, physician, medical personnel) can move the catheter in a proximal direction (e.g., performing a pull-back maneuver) or a distal direction (e.g., advancing the catheter). At the start of longitudinal movement, a first marker of one or more markers can be aligned with the skeletal reference point. As the physician pulls the catheter in the proximal direction, the physician can provide a second input, such as saying "two" when a second adjacent marker aligns with the skeletal reference point, which can be received by the processor 112 via input device 306. Movement can continue, and the physician can provide subsequent user-provided input to indicate when a third, fourth, fifth, ... nth marker aligns with the skeletal reference point. Based on the user-provided input, the processor 112 can calculate the position and / or longitudinal velocity of the catheter and imaging core during longitudinal movement.

[0103] Next, process 500 can move to step 508, where processor 112 can provide output to the user. Step 508 can be substantially similar to step 328. The output can be audio, tactile, visual, or a combination thereof. The output can indicate the longitudinal position of the catheter and / or the speed of longitudinal movement. In some embodiments, the output can include one or more IVUS images and / or strip images. The one or more IVUS images and strip images can include annotations indicating the longitudinal position of the catheter.

[0104] Figure 5B An operator-to-system interaction process 600 for detecting manual longitudinal movement of an IVUS catheter, according to one embodiment, is illustrated. Figure 5BThe operator-to-system interaction process 600 shown is an example process. In some embodiments, the operator-to-system interaction process 600 may include more or fewer steps. In some embodiments, one or more steps of process 600 may be performed in a different order, or simultaneously with one or more other steps of process 600. In one embodiment of operator-to-system interaction, the operator provides input to the system regarding the progress of manual catheter translation during the acquisition of an imaging series. For example, as the catheter markers pass a skeletal reference seen in fluoroscopy, the user may aloud count the catheter markers, such as “start, one, two, three,” etc., and provide auditory input to the microphone. In this embodiment, the spatial distance mapping between image capture time and longitudinal position will be an interpolation function based on the operator input. In one embodiment, the system may detect error conditions and reject spatial measurement calculations. For example, if a missed duplicate or out-of-order count is detected, or if a severely uneven count is detected, the system may reject the spatial measurement and notify the user so that they can repeat the action as desired. In one embodiment, the translation progress indicator may be a voice command, such as in the example embodiments described above, or another input interface mechanism, such as a tactile user input device, like a display screen, a button, or a foot switch. The ability to audibly indicate translation progress through unique counting / commands, such as verbal commands like “start, one, two, three,” rather than nonspecific commands, can potentially improve accuracy and robustness. In one embodiment, a nonspecific progress indicator, such as a verbal “mark, mark, mark” indication, or a foot switch tap, or tapping on the duct body if, for example, a tactile sensor is provided, would be sufficient.

[0105] According to one embodiment, the operator-to-system interaction process 600 may begin at step 602, where the IVUS catheter system processor, such as processor 112, begins recording a series of images. Next, the process 600 may proceed to step 604, where processor 112 marks each unit distance progress based on input provided by the user.

[0106] In some embodiments, step 604 may include the processor receiving one or more pacing inputs from the user / operator as described above. Similar to steps 324, 326, and 328 described above, processor 112 may determine the longitudinal position of the catheter based on one or more pacing inputs. In some embodiments, processor 112 may associate one or more IVUS images with the longitudinal position of the catheter at the time the one or more IVUS images were captured. For example, processor 112 may annotate the IVUS images to include the longitudinal position.

[0107] Process 600 can proceed to step 606, where IVUS image recording ends. In some embodiments, the IVUS catheter system may receive input from the user to stop recording IVUS images. Next, process 600 can proceed to step 608, where the processor may prompt the user to accept or reject longitudinal waypoint location data. As discussed above, processor 112 may provide the user with annotated IVUS images as output. Processor 112 may also provide a user interface, such as a software interface, that allows the user to review the annotated IVUS images and accept or reject the annotated longitudinal location data.

[0108] In several embodiments, it is advantageous to use complementary imaging modalities, such as fluoroscopy or a series of radiographic images, to assess the progression of the IVUS catheter through anatomical references close to vascular anatomy structures of interest, such as skeletal references near lesions of interest. Figures 6A to 6D The illustration shows a reference X-ray image of an IVUS catheter with a series of equally spaced radiopaque markers, each marker traversing a point on a reference reference. By providing knowledge that keyframes of the IVUS strip images are separated by known longitudinal distances, interpolation can be used to infer the spacing of the entire image series. For example, the strip images can then be reconstructed relative to a distance-based longitudinal axis rather than time. In one embodiment, frames of the IVUS series, such as the longitudinal distance between the expected start and end points of stent placement, can be conveniently estimated and documented. In one embodiment, the insertion depth can be determined using a visual indicator (insertion depth marker) of the progress on the catheter body through a fixed reference, such as the catheter inserter sheath.

[0109] Figure 6A This is an X-ray image showing the positioning of multiple markers 1002 relative to a reference point 1004. As discussed above, an IVUS catheter system may include one or more markers 1002. The markers 1002 may be positioned longitudinally along the catheter body 1006. In some embodiments, such as Figures 6A to 6D In the embodiments shown, one or more markers may be radiopaque. Reference point 1004 may be any anatomical point as described above. For example, catheter body 1006 may be inserted into the patient's leg in a downward direction, such that the catheter passes through the knee, and reference point 1004 may be the intercondylar fossa.

[0110] According to some embodiments, one or more markers 1002 can be used to determine the position of the catheter body 1006 relative to a reference point. For example, the longitudinal position of the catheter body 1006 and one or more transducers disposed therein can be determined during longitudinal movement of the catheter, for example, longitudinal movement of the catheter body 1006 in the proximal direction. In some embodiments, the markers 1002 may be evenly spaced along the longitudinal direction of the catheter body 1006 to allow a user to determine the distance the catheter body 1006 has traveled longitudinally relative to the reference point 1004. This process in Figures 6A to 6D The above-described system-to-operator and operator-to-system embodiments are shown and can be implemented.

[0111] like Figure 6A As shown, the first marker in marker 1002 has reached the reference point 1004. The catheter body 1006 can be pulled back by one marker distance, that is, the distance corresponding to the space between the two markers. Figure 6B As shown, after the catheter body 1006 has moved one marker distance in the proximal direction, the user can confirm this distance by verifying that the second marker in marker 1002 is now aligned with the reference point 1004 and that the first marker of marker 1002 has moved past the reference point in the proximal direction. This process can be repeated as the catheter body 1006 moves longitudinally during the procedure. For example, the catheter body 1006 can continue to move in the proximal direction during longitudinal movement, causing more markers 1002 to pass the reference point 1004. Figure 6C In the middle, two markers in marker 1002 have passed reference point 1004, and in Figure 6D In the middle, the three markers in marker 1002 have passed the reference point 1004.

[0112] Encoder usage in some embodiments In several embodiments, the manual movement of the measuring device and method involves capturing and recording a series of IVUS images while manually retracting or inserting the catheter along the blood vessel, simultaneously measuring and recording the relative or absolute insertion depth of the catheter using measuring devices, such as axial translational position measuring devices (e.g., encoders, position sensors, alignment devices, etc.) at or near the location where the catheter is inserted into the patient's body. In one embodiment, the insertion depth data is used to estimate the spatial location of the images along the length of the vessel in the series. Using this data, the image series can be rendered relative to a length axis. With this spatial alignment, strip images can be created and displayed. In one embodiment, the image series can be rendered and displayed relative to a longitudinal length axis, the longitudinal length, or the distance between relevant locations within the series. The distances between anatomical points of interest can be obtained with sufficient accuracy, and detailed IVUS images aid in clinical therapeutic decisions, such as the preferred balloon length and / or expandable stent length for percutaneous endovascular angioplasty. In various embodiments, a method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter may include: manually moving the IVUS catheter along its longitudinal axis; capturing multiple images with the IVUS catheter while moving it along its longitudinal axis in a proximal or distal direction; measuring the distance traveled by the IVUS catheter using a device for encoding; correlating image or tissue features in the multiple images with the distance traveled by the IVUS catheter; and determining the longitudinal length between the images of the tissue features based on the distance measured by the device for encoding. The device for encoding may include, or substantially consist of, for example, an encoder not associated with a mechanical actuator or motor. In various embodiments, the device for encoding is mechanical, optical, inductive, and / or capacitive (or a combination thereof). Such methods can avoid capturing fluoroscopic images or images from alternative imaging modalities to reduce X-ray exposure and simplify the measurement process.

[0113] Measurements of axial translation of the catheter position taken from outside the patient's body may differ slightly from measurements of the catheter tip position containing the imaging core. Relative movement along the bends and curves of the interventional vascular system, the non-rigid nature of body tissues, and / or pulsatile blood pressure introduce hysteresis between measurements taken at the catheter tip and those taken outside the patient's body. Inferring the translational distance of the catheter tip based on relative or absolute catheter insertion depth (measured outside the body or at the insertion point) depends on the stability of the catheter path or "track" within the body's vascular system. The measurement difference between tip translation and insertion depth can be characterized as a simple hysteresis that can be addressed by ignoring the initial period of imaging when the "relaxation" is removed.

[0114] Figure 7The illustration shows the hysteresis between translation at the catheter insertion point and translation at the catheter tip. In one embodiment, the initial portion of the IVUS strip image (e.g., the first and second IVUS images) can be ignored or adjusted to account for hysteresis introduced by eliminating stress in the catheter-vascular pathway system, such as relaxation or stabilization. Such exclusion periods or adjustments can be calibrated a priori for a clinical scenario. Such exclusion periods or adjustments can be communicated via software analysis of the strip images. In several embodiments, software can be used to detect disqualification cases to improve reliability. Systemic checks on catheter longitudinal movement, such as the rate and continuity of longitudinal movement, can be beneficial. For example, irregularities in longitudinal movement measured at the insertion point may indicate an unfavorable relationship between tip movement and insertion point movement. In one embodiment, software analysis of the images, such as estimating frame-to-frame differences, can be used to monitor the quality of longitudinal movement and associated strip images. For example, time periods with significantly more stable images may indicate an unfavorable relationship between tip movement and insertion point movement. In one embodiment, if a spatial alignment measurement is rejected due to an internal quality check, the software can provide an automated workflow to notify the user and suggest a retry of the measurement. In addition to using insertion depth data alone, other algorithms within the system software can be used to improve spatial alignment measurements.

[0115] In several embodiments, image data can be used to improve measurement performance by analyzing images during manual longitudinal movement of the catheter. Image difference magnitude, speckle decorrelation rate, optical flow, or similarity search between sub-regions may help enhance the motion estimation provided by the encoder. Images from alternative modalities, such as fluoroscopy, can be used to improve performance, for example, by identifying features of the IVUS catheter within the body as manual longitudinal movement of the catheter proceeds. Methods for improving performance may enhance motion estimation throughout the movement or may simply be intended to address hysteresis.

[0116] In various embodiments, the insertion depth coding device can communicate wirelessly with a separate imaging system or be connected via a wire. The insertion depth coding device can be integrated into a catheter inserter sheath, guide catheter, or a separate device. The insertion depth coding device can be attached to a catheter inserter sheath, guide catheter, or separately fixed near the point of catheter insertion into the body. The insertion depth coding device can generate absolute insertion depth data or relative insertion depth data.

[0117] In one embodiment, the encoder device is continuously active (e.g., not only during the capture of an image series). Continuous, active longitudinal translation information (e.g., orientation, additional feedback such as total insertion depth) can also provide the user with information useful for adjusting imaging settings during different phases of the procedure. In one example, a deeper penetration setting might be useful when the catheter is moved in one direction and at a higher resolution in another.

[0118] Figure 8 An embodiment of a relative insertion depth measuring device using a longitudinally translating mechanical encoder fixed near the point where the catheter is inserted into the patient's body is illustrated. In one embodiment, the relative insertion depth measuring device is a mechanical encoder module 1100. The catheter 1105 may pass through the encoder module 1100, or the encoder module 1100 may be positioned to contact the catheter 1105 (e.g., partially or fully engaged around the circumference).

[0119] In various embodiments, the encoder module 1100 may include (i) a small device positioned at the point of catheter insertion into the body; (ii) the device may be handheld, for example, a displacement encoder held by hand on the inserter sheath to stabilize the insertion point while performing longitudinal translation measurements if clinical practice dictates holding the inserter sheath during insertion or retraction of the catheter to create an IVUS image recording; (iii) relative insertion depth measurements performed by the device, recorded synchronously with image capture; (iv) optionally including or excluding special markings or design features required on the catheter body; (v) the device may be disposable; (vi) the device may be re-sterilizable for frequent reuse; and / or (vii) one or more encoder technologies may be used to sense catheter movement. In some embodiments, the catheter body may not include any telescopic members, such as a telescopic member with an inner member disposed within the lumen of the outer sheath to allow axial movement of the inner member within the outer sheath. In some embodiments, the catheter body may not include a tracking guide or skid for moving the imaging unit.

[0120] In several embodiments, a longitudinal translation inductive encoder is used relative to the insertion depth measuring device. In one embodiment, a linear variable differential transformer (LVDT) module 1200 can be used to measure the linear translation of the conduit, such as... Figure 9A and Figure 9BAs shown in the figure. The LVDT module 1200 may include a longitudinal translation sensor for measuring IVUS movement in the longitudinal direction. In one embodiment, the catheter 1205 can be manually moved (e.g., axially translated). In several embodiments, the LVDT module 1200 may include (i) a housing 1210 having primary and / or secondary windings surrounding the catheter 1205, (ii) a housing 1210 that can remain stationary when the catheter 1205 is longitudinally translated, and / or (iii) a core 1220 that can be attached to the catheter 1205. In one embodiment, the housing 1210 may be secured to a sheath outside the patient's body. In one embodiment, the core 1220 may be a torque coil and / or a ferrite core secured to the catheter 1205 via a clamshell latch. In one embodiment, the housing 1210 may include a primary excitation winding 1212, a secondary left winding 1214, a secondary right winding 1216, and / or a communication component 1218 configured to communicate data with a relative insertion depth measurement device. The communication component 1218 can be wired or wireless (e.g., Bluetooth). Figure 9C The diagram shows a schematic circuit diagram of the operation of the LVDT module 1200.

[0121] Figure 10A schematic diagram of a coupling sensor according to one embodiment is depicted. In several embodiments, the relative insertion depth measuring device may employ one, two, or more longitudinal translation inductive encoders. In one embodiment, one or more coupling sensors 1302, 1304 may be used. In one embodiment, the coupling sensor coil may comprise a primary excitation coil and a secondary receiving coil. The catheter torque coil may be made of iron or ferrite material. When the torque coil is translated through the first, proximal / primary sensor winding coil and the second, distal sensor winding coil, this may result in a phase shift of the signal received in the secondary winding. The phase shift can be measured to sense length or movement. The first sensor (coil) 1302 may be located at the proximal end of the catheter body 1304 and the second sensor (coil) 1306 may be located near the inlet of the catheter entering the sheath. Both the first sensor 1302 and the second sensor 1306 may be located outside the catheter body 1304 and the catheter may be retracted (pulled) or inserted (pushed) through the distal coil 1306. The proximal end coil 1302 can be fixed at the proximal end relative to the conduit and can be excited with a narrowband alternating current in the frequency range of 1 kHz to 100 MHz (e.g., 1, 2, 5, 10, 15, 20, 25, 50, 100, 200, 300, 400, 500 kHz, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 MHz, and any values ​​and ranges therein). The alternating current of the proximal coil 1302 can generate a magnetic field that can be coupled to the distal coil 1306 through an iron (e.g., stainless steel) cable conduit of the imaging core in the conduit body 1304. The distal coil 1306 can be a receiving coil. The phase difference between the excitation signal at the near-side coil 1302 and the received signal captured by the far-side coil 1306 corresponds to the magnetic field propagating through the cable conduit length between the near-side and far-side coils (1302 and 1306, respectively). Changing the length of the cable conduit section between the near-side coil 1302 and far-side coil 1306 during pull-back alters the relative phase, which can be used to determine the change in length. The phase can be determined by precise timing measurement of the received signal relative to the excitation signal, by complex demodulation of the received signal using a frequency locked to the excitation signal, or by other means of measuring the relative phase.

[0122] In several embodiments, the relative insertion depth measuring device may employ a longitudinal translation optical encoder. In one embodiment, the relative insertion depth measuring device may be a longitudinal translation optical encoder module. In various embodiments, optical measurement may include (i) processing of surface irregularities or textures and cross-correlation between successive images, (ii) utilizing printed patterns on the catheter, such as visual markings, QR codes, handwriting capture systems, or custom markings on the catheter, and integration with the inserter sheath, guide catheter, etc. Laser technology may also be used similarly. In one embodiment, such as Figure 11 As shown, the optical encoder 1400 can measure changes in position by optically acquiring continuous surface images or frames and mathematically determining the direction and magnitude of movement. In one embodiment, the optical encoder 1400 may include a light source 1410 (e.g., an LED), a lens 1412 (e.g., a light channel) in a housing 1402, and an optical sensor 1420 (e.g., an image sensor, a light sensor) that optically acquires surface images from the channel 1405. In one embodiment, the optical encoder may be independently battery-powered and may optionally include Bluetooth wireless (wireless) connectivity to improve ease of use.

[0123] Figure 12An embodiment of a relative insertion depth measuring device is illustrated using an axial translational mechanical encoder fixed near the point where the catheter is inserted into the patient's body. In one embodiment, the relative insertion depth measuring device is a mechanical encoder module 1100. The catheter 1105 may pass through the encoder module 1100, or the encoder module 1100 may be positioned to contact the catheter 1105 (e.g., partially or fully engaged around its circumference). In one embodiment, a wheel 1130 partially engages the catheter 1105 by straddling the catheter body, wherein a mechanism 1120, such as a hinged arm with spring-loaded pressure, engages the wheel 1130 using frictional pressure to measure the movement of the catheter 1105. An encoder 1110 is positioned at the axis of the wheel 1130 and provides the system with directional and pullback distance information. In one embodiment, the information is transmitted via Bluetooth. In various embodiments, the encoder module 1100 may include (i) a small device positioned at the point of catheter insertion into the body; (ii) the device may be handheld, for example, a displacement encoder held by hand on the inserter sheath to stabilize the insertion point while translational measurements are being performed if clinical practice dictates holding the inserter sheath as the catheter is pulled back to create an IVUS image recording; (iii) relative insertion depth measurements are performed by the device, which is recorded synchronously with image capture; (iv) optional inclusion or exclusion of special markings or design features required on the catheter body; and / or (v) one or more encoder technologies may be used to sense the movement of the axle, such as orthogonal optical beam-breaking sensors and perforated wheels. In some embodiments, the catheter body may not include any telescopic members, such as a telescopic member with an inner member disposed within the lumen of the outer sheath to facilitate axial movement of the inner member within the outer sheath. In some embodiments, the catheter body may not include a tracking guide or skid for moving the imaging unit.

[0124] Although disclosure is provided on systems with and without encoders, the features of the non-encoder embodiments described herein can be used with encoder embodiments and vice versa.

[0125] In several embodiments, an impedance-based system can be used to determine the location of an IVUS catheter within a patient. According to several embodiments, the location of the IVUS catheter can be based on the location of an imaging core within the patient. The impedance-based system can include one or more catheter electrodes disposed on or within the IVUS catheter. For example, one or more catheter electrodes can be disposed on or integrated into a catheter sheath. The impedance-based system can also include one or more external electrodes. According to several embodiments, one or more external electrodes can be placed on or within one or more patches placed at one or more predetermined locations on the patient's skin. The one or more catheter electrodes and the one or more external electrodes can form an open circuit, with at least one gap between the catheter electrode(s) and the external electrodes(s). At least one processor, such as processor 112, can be positioned to electrically communicate with the catheter electrode(s) and the external electrodes(s).

[0126] During operation of an IVUS system utilizing an impedance-based system, at least one processor 112 may instruct one or more catheter electrodes to generate one or more electrical signals. These electrical signals may travel through the patient to one or more external electrodes to generate one or more return signals corresponding to each of the one or more external electrodes. In several embodiments, at least one processor 112 may determine the position of the IVUS catheter, the longitudinal movement of the IVUS catheter, and / or the velocity of the IVUS catheter based on the impedance of the one or more return electrical signals and the predetermined positions of the one or more external electrodes on the patient's skin. At least one processor 112 may generate a three-dimensional map of the patient's vascular system based on the IVUS catheter position determined by the impedance-based system and IVUS images captured during the procedure. In some embodiments, the impedance-based system may be implemented using the system-to-operator embodiment described above, the operator-to-system embodiment, a relative insertion depth device, and / or an encoder.

[0127] This document provides several embodiments of medical imaging systems, such as IVUS systems. Advantageously, according to several embodiments, such systems include one or more improvements over conventional IVUS systems, such as enhanced imaging, image-guided therapy, enhanced usability, easier setup, streamlined clinical procedures, reduced operation time, improved clinical outcomes, improved accuracy of diagnostic images, improved accuracy of therapeutic intervention delivery, improved guided interventional therapy, more efficient peripheral interventions, faster informed therapeutic decisions, and faster measurement and reporting. In some embodiments, IVUS is a diagnostic image-guided therapy tool for treating both peripheral arterial and venous diseases, enabling 2D and / or 3D intraluminal visualization.

[0128] For example, image interpretation and lumen geometry measurements can be performed using non-flushing catheters (e.g., diameter, stenosis, peripheral intervention, coronary intervention, atherosclerosis resection, lithotripsy, intravascular lithotripsy (IVL), balloon placement, stent placement, venous procedures, below-knee (BTK) procedures, arteriovenous fistulas, and other procedures). Interventional cardiologists, radiologists, and / or vascular surgeons can perform procedures in hospitals, physician offices, office-based laboratories (OBLs), and / or outpatient surgical centers (ASCs). In several embodiments, the systems described herein can be used effectively in hospitals and OBLs / ASCs without the need for specialized clinical support. Interventions can include therapies or other interventions such as peripheral interventions, coronary interventions, atherosclerosis resection, IVL, balloon placement, stent placement, venous procedures, BTK procedures, AV fistulas, and other procedures. Imaging can include, for example, IVUS imaging of non-coronary peripheral vessels, IVUS imaging of coronary vessels, ultrasound imaging, intraluminal imaging, imaging of body cavities and organs, and other imaging methods (and combinations thereof) described herein.

[0129] Many of these embodiments should particularly benefit ensuring that patients do not receive unnecessary additional diagnoses or interventions, which in turn provides better patient care and reduces the short-term burden on the healthcare system. Similarly, many of these embodiments help patients receive the necessary additional diagnoses or interventions they require, 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, IVUS systems with flush-free catheters provide contemporary IVUS platforms and catheter kits that offer improved availability at a competitive cost with excellent image interpretation and a streamlined bedside workflow, enabling wider adoption.

[0130] In several embodiments, one or more of the following features are provided: Plug-and-play catheters: According to several embodiments, flush-free catheters are optimized for vascular imaging and configured for excellent maneuverability, tracking, and traversal of arterial and venous vascular systems. In several embodiments, the catheter has excellent maneuverability to avoid kinking and sufficient column strength to allow the catheter to be advanced through tortuous bends and occlusions in the vascular system without bending, excessively bending, or collapsing anywhere along the catheter (e.g., the ability to traverse occlusions or constrictions). In several embodiments, the catheter has excellent tracking ability because it can follow the guidewire through tortuous bends in the vascular system, with sufficient flexibility and strength to move and advance along the guidewire to a target location within the vascular system. In several embodiments, the catheter has superior traversal ability to traverse occlusions, restriction, and constrictions within the vascular system, such as at sites with tissue obstruction (e.g., stenosis, etc.) and / or implanted obstruction (e.g., stents, balloons, etc.). Systems described herein, such as IVUS catheters, may incorporate a plug-and-play rotational design and, for example, may allow the catheter to be removed from its sterile packaging and ready for use without the need for flushing equipment. In one embodiment, the catheter has a single rotating ultrasound element. In several embodiments, the catheter contains a coupling medium (e.g., coupling medium, medium, liquid, fluid, gel, etc.) encapsulated within the catheter sheath that supports the rotating imaging core. In one embodiment, the IVUS catheter is a plug-and-play catheter with a non-rinsing external peripheral disposable imaging design, having a total length of 280 cm and 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 a catheter interface module (CIM) outside the sterile field. In one embodiment, the IVUS catheter is a plug-and-play catheter, a non-rinsing external peripheral disposable imaging catheter with a total length of 250 cm and 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 a CIM outside the sterile field. Optionally, external connection to the sterile field avoids the need for a wired motor unit to be laid inside the sterile field. In several embodiments, high-resolution (e.g., HD, UHD, UHD, HD+, etc.) imaging uses acoustic pulse echoes with matched excitation spectra for optimal penetration, ultra-high resolution, and high-resolution image quality. In several embodiments, the system is optimized for peripheral vascular imaging, coronary artery imaging, or both. In one embodiment, the imaging core rotates within a polymer sheath using an internal drive shaft connected via a proximal hub / connector. The hub connector can optionally be attached to the CIM after removal from the sterile catheter package. A transducer located at the distal end of the imaging core can rotate at speeds from 1500 rpm to 4000 rpm and receives the echoes for processing into a circular image on a flat panel display. The catheter length can be 8 to 10 feet.In various embodiments, the catheter can be removed from its sterile packaging and ready for use without flushing the device. This length allows the catheter's proximal connector to connect to the CIM outside the sterile field. In one embodiment, connecting outside the sterile field avoids the need to lay the wire motor unit inside the sterile field. The catheter may include non-volatile memory containing unique catheter identification, usage data, and calibration for optimal imaging performance. According to some embodiments, calibration may include data related to measurements of impedance versus frequency, acoustic sensitivity versus frequency, and / or device-specific bundle profile data.

[0131] Catheter Interface Module (CIM): According to several embodiments, the CIM is a hardware interface between a system cable from a workstation and a disposable catheter. In several embodiments, the CIM provides rotation drive and ultrasound signal processing capabilities for the system (e.g., an IVUS system). Custom electronics control the motor that rotates the imaging core inside the catheter. The electronics can also transmit and receive ultrasound signals between a rotary transducer inside the distal end of the catheter and a custom printed circuit board inside the workstation. In various embodiments, the CIM provides an interface to read and write, for example, to non-volatile memory within the catheter. The memory can be used to calibrate the ultrasound transducer for each unique catheter. In one embodiment, the catheter memory can be used to select an appropriate system configuration to achieve the best possible imaging performance. The CIM can transmit ultrasound signals, sensor data, and / or catheter information from the catheter to a workstation and / or at least one user interface device (e.g., a tablet computer, computer, etc.) that can store the transmitted information in non-volatile memory in one or more locations. In one embodiment, the CIM is mounted on a bed rail outside the sterile area. In several embodiments, the CIM is embedded or integrated into imaging control equipment, workstations, housings, tables, beds, bases, platforms, and / or trolleys. In some embodiments, the CIM is located outside the sterile field. In some embodiments, one or more ports are provided to allow seamless connectivity between the IVUS system and other imaging modalities.

[0132] Image Co-registration: In several embodiments, the IVUS system provides co-registration data to provide 1:1 co-localization identification to enable therapeutic accuracy. Advantageously, several embodiments described herein can work collaboratively or independently with co-registration in another imaging modality, such as fluoroscopy, in which software algorithms track one or more radiopaque (RO) catheter markers or RO transducers throughout the continuous fluoroscopy recording. For example, co-registration with angiography can be used to determine the 3D shape of vessels, lumens, and lesions, including lesion length, effective stent selection, and effective stent landing site, in an attempt to shorten procedure time, reduce contrast agent use, and make IVUS more comfortable for the physician. Several embodiments described herein achieve one or more of these benefits with or without automated co-registration.

[0133] Synergistic effects of 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 for non-vascular intraluminal applications, such as in endoscopy.

[0134] For example, an endoscope can be used in conjunction with some of the features described herein. Transvaginal and other gynecological ultrasound devices may also incorporate some of the features described herein. For embodiments in which EUS (endoscopic ultrasound) and other intraluminal imaging or imaging of other body cavities or organs (and such imaging is not in blood vessels) are performed, the features described herein for “IVUS” or “catheter” should be understood to be applicable to intraluminal (or other cavity / organ) catheters, probes, tubes, endoscopes and other such devices.

[0135] In some embodiments, the system and method are configured and optimized for peripheral vascular surgery (and not for coronary vascular surgery). In one embodiment, systems and methods configured, designed, or modified, either alone or primarily for peripheral vascular systems, include one or more of the following characteristics: flexibility, maneuverability, length, diameter, material, and / or bending strength to improve maneuverability, tracking, and traversal (e.g., the ability to traverse barriers or stenosis) within the lumen. Some of these characteristics may also be incorporated into applications beyond peripheral IVUS. In some embodiments, the system is configured to image and / or measure tissue prior to therapeutic surgery, such as to identify and plan the therapeutic procedure. In some embodiments, the system is configured to image and / or measure tissue after therapeutic surgery, such as to confirm the outcome and therapeutic effect of the therapeutic procedure. In some embodiments, the system is configured to image and / or measure tissue during therapeutic surgery.

[0136] Artificial Intelligence: In several embodiments, the systems described herein, including, for example, advanced intravascular ultrasound platforms, utilize AI to enable measurements, image interpretation, enhance the capabilities of the entire system, and streamline workflows to maximize clinical value. In some embodiments, advantageously, physicians are not required to spatially and temporally integrate imaging data to fully interpret clinical conditions. Indeed, systems according to several embodiments described herein can leverage the capabilities of generationally advanced AI to go beyond single-image interpretation. In several embodiments, for example, the AI-powered engine may comprise a workstation that enhances image interpretation through a streamlined workflow to improve overall usability. Machine learning is used in several embodiments. In one embodiment, AI-ready processing capabilities are designed to support real-time and on-demand image interpretation. The AI-powered workstation can provide high-end processing and AI engines for advanced signal and image processing. In various embodiments, native image data capture provides superior image interpretation (e.g., boundary detection, identification and measurement of vessel size, vascular disease, dissection, plaque morphology, etc.). In several embodiments, the systems described herein provide simplified measurements via automated boundary detection (e.g., AI algorithms automatically identify boundaries of lumens, vessels, tissues, lesions, plaques, etc.). In several embodiments, the system provides simplified measurements via semi-automatic boundary detection (e.g., an automated AI algorithm that identifies the boundaries of lumens, vessels, tissues, lesions, plaques, etc., can be manually adjusted or modified by the user, with boundary selection reconfigured based on user modifications). In one embodiment, AI plaque identification utilizes an AI algorithm to automatically classify and identify plaque types within the imaging area to provide user guidance on treatment options (e.g., color coding, icons, or text overlays can be used to indicate what type of conditions, such as plaques, might be present in the selected image). In several embodiments, the data-driven platform is designed to collect data, streamline image interpretation, leverage AI processing capabilities 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 the true lumen. In some embodiments, image interpretation is used to identify thrombi, thrombus formation, clots, embolisms, plaques, calcium, tissue health, stent or balloon attachment, and / or stent or balloon “health” or conditions. Image interpretation may involve imaging to assess the quality and / or location of existing stent placement. Image interpretation may involve identifying the location relative to the luminal wall and determining the level and / or quality of tissue growing within and around the stent or balloon.In one embodiment, for example, for a bioresorbable stent, image interpretation may involve (i) assessing the amount of stent dissolution and (ii) determining whether the stent dissolution conforms to the expected attenuation pattern (e.g., determining whether the attenuation level on one side of the stent is similar to that on the other side; if not, this may indicate a problem with stent placement, or if the stent dissolves faster than expected, this may indicate that the stent is not providing the expected structural support to the tissue). In one embodiment, high-fidelity ultrasound data is used to drive improved image generation and interpretation, with options for leveraging artificial intelligence and / or machine learning. In various embodiments, catheters, devices, systems, and methods may be configured to perform edge-based machine learning computations associated with images or image analysis, using artificial intelligence algorithms to identify tissue boundaries, plaques, calcium, thrombi, dissections, and / or stent attachments. In some embodiments, data, algorithms, AI, and / or ML are used to acquire data from one or more sensors and provide feedback on operational aspects such as imaging parameters via feedback loops (e.g., closed feedback loops / automatic) or through user-guided tuning. 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 therapies via feedback loops (e.g., closed feedback loops / automatic) or via user-guided adjustments.

[0137] In several embodiments, the imaging described herein is used to diagnose whether a patient is suitable for a particular intervention or further diagnosis. In various embodiments, 2D and / or 3D intraluminal visualization is enabled. In one embodiment, 2D imaging comprises images in a single plane. In several embodiments, 3D imaging comprises a volumetric representation of tissue or lumen. In some embodiments, 3D imaging is reconstructed via algorithms that interpolate a series of 2D images across a third dimension, acquire a series of individual 2D images and estimate linear progression along the third dimension, and employ artificial intelligence (AI) to generate 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 the location along the vein or artery (e.g., insertion length) can be recorded by an encoder or other sensor. Drawing each 2D cross-section in 3D at the insertion length of the recorded cross-section can allow the creation of a 3D model of the vascular object. In one embodiment, adding an electromagnetic sensor to the catheter tip can allow the location of the catheter tip to be recorded while acquiring 2D images, thereby allowing the creation of a 3D model of the vascular structure. In one embodiment, one or more algorithms convert a series of IVUS 2D images and signal data into a volumetric 3D visualization. In one embodiment, 3D visualization is generated via interpolation of linear and / or nonlinear vascular structure geometry and acoustic reflections from the tissue. In one embodiment, pixel-based interpolation is used for three-dimensional visualization of vascular anatomy. In several embodiments, a series of cross-sectional two-dimensional IVUS images and / or signals are generated via a cross-sectional view image of a blood vessel based on pixels illustrating acoustic reflection information along the luminal length. In one embodiment, 3D visualization is generated via an algorithm that creates anatomical contour boundaries through smooth 3D surface rendering. In several embodiments, AI is employed to create 3D visualization data and images.

[0138] In several embodiments, coronary artery systems and methods are provided. In several embodiments, devices such as coronary IVUS catheters employ smaller diameters, higher rigidity, and improved coronary artery-specific maneuverability, tracking, and / or traversal characteristics. Catheters used for coronary applications can employ different ultrasound frequencies to address variations in tissue lumen size: for example, peripheral vascular systems may have larger vessel diameters, thus lower frequencies can be used for ultrasound imaging to image at greater distances from the IVUS catheter transducer. In some embodiments, coronary vessels have smaller diameters, thus imaging ultrasound frequencies of approximately 60 MHz can be used, while peripheral imaging can use lower frequencies such as approximately 40 MHz or lower. In some embodiments, the coronary IVUS catheter requires lower column strength for maneuverability or traversal due to the presence of a guide catheter.

[0139] In several embodiments, catheters optimized for vascular imaging are configured for excellent maneuverability, tracking, and traversal of peripheral vascular systems of arteries and veins. In several embodiments, one or more of the following features are provided: Maneuverability: In several embodiments, the catheter exhibits excellent maneuverability to avoid kinking and sufficient column strength to allow it to be advanced through tortuous bends and occlusions in the blood vessels without flexing, excessively bending, or collapsing anywhere along the catheter (e.g., approaching or (e.g., the ability to traverse occlusions or constrictions)). In some embodiments, material properties (e.g., a balance of rigidity and flexibility, stiffness of individual segments), and dimensional properties (e.g., larger dimensions, such as diameter and thickness) increase column strength, addressing greater maneuverability and resistance to kinking.

[0140] Tracking: In several embodiments, the catheter has excellent tracking capabilities because it can follow the guidewire through the twists and turns of the vascular system, possessing sufficient flexibility and strength to move and advance along the guidewire to the target location within the vascular system. A hydrophilic coating, according to some embodiments, helps reduce friction with surrounding luminal tissue.

[0141] Transverse: In several embodiments, the catheter has superior traversal capability to traverse occlusion, restriction, and constriction within the vascular system, such as at sites of tissue obstruction (e.g., stenosis, etc.) and / or implanted obstruction (e.g., stents, balloons, etc.). According to some embodiments, traversal capability is enhanced by one or more of the following: (i) the design of the distal tip (e.g., sufficiently sharp to navigate the occlusion, etc., and sufficiently blunt to not obstruct the occlusion), (ii) material properties (e.g., a balance of rigidity and flexibility, stiffness in individual segments, etc.), and / or (iii) dimensional properties (e.g., larger dimensions, such as diameter and thickness, increasing column strength). In one embodiment, low stiffness near the distal tip provides flexibility for navigation through tortuous anatomy and obstacles. In one embodiment, a region with varying or stepped gradients of stiffness is provided that changes proximally to be sufficient to move the catheter while avoiding kinking. Individual stiffness and / or flexibility may remain constant along specific portions or all portions of the device.

[0142] Changes and modifications may be made to the embodiments described herein without departing from the principles of this disclosure. Each of the disclosed aspects and examples of this disclosure may be considered individually or in combination with other aspects, examples, and variations of this disclosure. Furthermore, unless otherwise stated, the steps of the methods of this disclosure are not limited to any particular order of execution.

[0143] While the methods and apparatus described herein may be susceptible to various modifications and alternatives, specific examples of which have been shown in the accompanying drawings and described in detail herein. Embodiments are not limited to the specific forms or methods disclosed, but are intended to cover modifications, equivalents, and alternatives falling within the spirit and scope of the various examples and embodiments described herein and / or in the appended claims. Furthermore, any particular feature, aspect, method, property, quality, attribute, element, etc., disclosed herein in conjunction with the examples may be used in all other examples set forth herein. No method disclosed herein needs to be performed in the order stated. Unless otherwise specifically stated or understood in the context in which it is used, the use of sequential or temporal language, such as “then,” “next,” “after,” “following,” etc., is generally for the convenience of the flow of text, not to restrict the sequence of operations performed. Thus, some examples may be performed using the sequence of operations described herein, while others may be performed following a different sequence of operations.

[0144] The conditional language used herein, among other things, such as “may,” “will,” “may,” “for example,” etc., unless otherwise specifically stated or understood in the context of use, is generally intended to convey that certain examples include certain features, elements, and / or states, while other examples do not. Therefore, such conditional language is not generally intended to imply that one or more examples require features, elements, blocks, and / or states in any way, or that one or more examples must contain logic for determining, with or without author input or prompting, whether such features, elements, and / or states are included in any particular example or will be performed in any particular example. Where a device or method “comprises” certain features or steps, if so identified in the claims, such a device or method may also “consist substantially of” such features or steps.

[0145] The methods disclosed herein may include certain actions performed by a physician; however, the methods may also include any instructions from a user or third party, whether explicit or implicit, regarding those actions. For example, an action such as “locating the device” includes “instructing the device to be located.”

[0146] The scope disclosed herein also covers any and all overlapping, subranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between,” etc., includes the listed numbers. Numbers beginning with terms such as “approximately” or “about” include the listed numbers and should be interpreted on a contextual basis (e.g., as accurately and reasonably as possible within the context, such as ±5%, ±10%, ±15%, etc.). For example, “about 4 inches” includes “4 inches.” Phrases beginning with terms such as “substantially” include the cited phrase and should be interpreted on a contextual basis (e.g., as reasonably as possible within the context). For example, “substantially linear” includes “linear.” Unless otherwise stated, all measurements are performed under standard conditions including temperature and pressure. The phrase “at least one of…” is intended to require at least one item in the subsequent list, not a type of each item in each of the subsequent lists. For example, “at least one of A, B, and C” can include A; B; C; A and B; A and C; B and C; or A, B, and C.

Claims

1. A method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter, the method comprising: Move the IVUS catheter manually along its longitudinal axis. The IVUS catheter includes multiple markers spaced at predetermined intervals along its longitudinal axis. The multiple markers are visible through complementary imaging modalities; Multiple images are captured using the complementary imaging modality as the IVUS catheter is moved along its longitudinal axis in the proximal or distal direction. One or more location inputs from a user are captured using a recording device, the location inputs indicating the position of at least one of the plurality of markers having a predetermined distance relative to the dissection point; The one or more location inputs are associated with the multiple images based on the positions of the multiple markers when each of the multiple images is captured; The longitudinal distance between the one or more images is determined based on the predetermined interval distance between the markers; as well as The estimated longitudinal position of each of the plurality of images is determined by interpolating the longitudinal distance between the captured images at the position input.

2. The method of claim 1, wherein the method does not require co-registration with another imaging technique such as angiography.

3. The method according to claim 1, wherein the plurality of marks are uniformly spaced at a uniform interval ranging from 1 cm to 5 cm.

4. The method of claim 1, wherein the plurality of marks are uniformly spaced at a uniform interval ranging from 2 mm to 50 mm.

5. The method of claim 1, wherein the one or more location inputs are provided by the user speaking a single word as he passes each of the plurality of markers at the anatomical point.

6. The method of claim 1, wherein the one or more location inputs are individual spoken words associated with the process of passing through each of the plurality of markers at the anatomical point.

7. The method of claim 1, wherein the one or more location inputs include a press button.

8. The method of claim 1, wherein the one or more location inputs include tapping the IVUS catheter.

9. The method according to any one of claims 1 to 8, wherein the one or more position inputs include a tapping catheter interface module.

10. The method according to any one of the preceding claims, wherein the one or more position inputs include pressing a foot pedal.

11. The method according to any one of claims 1 to 8, further comprising providing visualization of the plurality of images having a distance based on the longitudinal axis.

12. The method according to any one of claims 1 to 8, further comprising measuring / reporting the longitudinal distance between two consecutive images of the plurality of images.

13. The method according to any one of claims 1 to 8, further comprising measuring / reporting the distance between two or more of the plurality of images.

14. The method according to any one of claims 1 to 8, wherein the complementary imaging modality is X-ray fluorescence fluoroscopy.

15. The method of claim 14, wherein the plurality of markers are seen progressing through the anatomical point in the fluoroscopy, and wherein the plurality of markers are seen progressing directly through the catheter sheath or some other fixation point outside the body.

16. The method of claim 14, wherein the plurality of markers are seen progressing through the anatomical point in the fluoroscopy, and wherein the plurality of markers are seen progressing directly through the guiding catheter.

17. The method according to any one of claims 1 to 8, wherein the IVUS catheter is moved by hand without the use of a linear actuation motor.

18. The method according to any one of claims 1 to 8, wherein the IVUS catheter does not include a telescopic component.

19. A method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter, the method comprising: An IVUS catheter is inserted into the patient, wherein the IVUS catheter comprises: Catheter body, One or more ultrasonic transducers are disposed within the catheter body; and One or more markings are provided longitudinally along the catheter body; Receive one or more mobile report inputs from the user; The length of the longitudinal movement is determined by the processor based on the one or more movement report inputs, wherein the longitudinal movement is caused by manual movement of the catheter body.

20. The method of claim 19, wherein the method does not require co-registration with another imaging technique such as angiography.

21. The method of claim 19, wherein the one or more mobile reporting inputs include one or more of the following: voice input, mechanical input, touch input, or a combination thereof.

22. The method of claim 19, wherein the one or more movement reporting inputs provide a rate of unidirectional movement.

23. The method of any one of claims 19 to 22, wherein the one or more movement reporting inputs include a reference position, wherein the reference position corresponds to the anatomical position of the catheter body relative to the patient.

24. The method of claim 23, wherein the one or more markings comprise one or more bands disposed on the outer surface of the catheter body or inserted into the interior of the catheter body.

25. The method according to any one of claims 19 to 22, wherein the one or more marks are non-transmissive.

26. The method according to any one of claims 19 to 22, further comprising detecting error conditions.

27. The method of claim 26, wherein the error condition is one of the following: incorrect tag order, duplicate tags, missing tags, or inconsistency detection of the one or more tags.

28. An intravascular ultrasound (IVUS) catheter system configured for detecting longitudinal position, the system comprising: The catheter body is configured to be placed within the lumen of a patient's blood vessel; One or more markers are provided along the catheter body; as well as The processor is configured as follows: Receive one or more mobile report inputs from the user; Determine longitudinal movement based on the one or more movement report inputs; and Output is provided to the user based on the longitudinal movement.

29. The system of claim 28, wherein the system does not require co-registration with another imaging technique such as angiography.

30. The system of claim 28, wherein the one or more mobile reporting inputs include one or more of the following: voice input, mechanical input, touch input, or a combination thereof.

31. The system of claim 28, wherein the one or more markings comprise one or more bands disposed on the outer surface of the catheter body or inserted into the interior of the catheter body.

32. The system according to any one of claims 28 to 31, wherein the one or more markings are non-transparent.

33. The system according to any one of claims 28 to 31, wherein the processor is further configured to detect error conditions.

34. The system of claim 33, wherein the error condition is one of the following: incorrect tag order, duplicate tags, missing tags, or inconsistency detection of the one or more tags.

35. A method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter, the method comprising: Move the IVUS catheter manually along its longitudinal axis. The IVUS catheter includes multiple markers along its longitudinal axis. The multiple markers are visible through complementary imaging modalities; Provides multiple step-adjustment outputs to the user based on a preset rate of unidirectional movement; Store multiple images with multiple markers at a series of locations relative to anatomical points; as well as The estimated longitudinal position of each of the plurality of images is determined based on the preset movement rate.

36. The method of claim 35, wherein the method does not require co-registration with another imaging technique such as angiography.

37. The method of claim 35, further comprising measuring / reporting the longitudinal distance between two consecutive images of the plurality of images.

38. The method of claim 35, further comprising measuring / reporting the distance between two or more of the plurality of images.

39. The method of claim 35, further comprising prompting the user to accept or reject the estimated longitudinal position for each of the plurality of images.

40. The method according to any one of claims 35 to 39, wherein the plurality of pacing outputs are auditory.

41. The method according to any one of claims 35 to 39, wherein the plurality of step outputs are tactile.

42. The method according to any one of claims 35 to 39, wherein the plurality of step-tuning outputs are visual.

43. The method according to any one of claims 35 to 39, further comprising providing visualization of the plurality of images having a distance based on the longitudinal axis.

44. The method according to any one of claims 35 to 39, wherein the plurality of marks are uniformly spaced apart at a uniform interval in the range of 1 cm to 5 cm.

45. The method according to any one of claims 35 to 39, wherein the plurality of marks are uniformly spaced apart at a uniform interval in the range of 2 mm to 50 mm.

46. ​​A method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter, the method comprising: An IVUS catheter is inserted into the patient, wherein the IVUS catheter comprises: Catheter body, One or more ultrasonic transducers are disposed within the catheter body; and One or more markings are provided longitudinally along the catheter body; Provide the user with one or more step adjustment commands; and Based on the one or more pacing instructions, the length of longitudinal movement of the catheter body is determined via a processor, wherein the longitudinal movement is caused by manual movement of the catheter body.

47. The method of claim 46, wherein the method does not require co-registration with another imaging technique such as angiography.

48. The method of claim 46, wherein the one or more pacing instructions indicate a longitudinal movement speed to the user.

49. The method of claim 48, wherein the longitudinal moving speed is in the range of 1 mm / sec to 20 mm / sec.

50. The method of claim 48, further comprising receiving the longitudinal movement speed from the user.

51. The method according to any one of claims 46 to 50, wherein the one or more pacing instructions include one or more of the following: audio output, tactile output, and visual output.

52. The method according to any one of claims 46 to 50, further comprising: Collect IVUS images; as well as The IVUS images are annotated based on the longitudinal movement of the catheter body.

53. The method according to any one of claims 46 to 50, wherein the one or more markings comprise one or more bands disposed on the outer surface or inserted inside the catheter body.

54. The method according to any one of claims 46 to 50, wherein the one or more marks are non-transmissive.

55. The method according to any one of claims 46 to 50, further comprising detecting error conditions.

56. The method of claim 55, wherein the error condition is one of the following: incorrect tag order, duplicate tags, missing tags, or inconsistency detection of the one or more tags.

57. An intravascular ultrasound (IVUS) catheter system configured for detecting longitudinal position, the system comprising: The catheter body is configured to be placed within the lumen of a patient's blood vessel; One or more markers are provided along the catheter body; as well as The processor is configured as follows: Provide the user with one or more step adjustment commands; The length of the longitudinal movement is determined based on the one or more pacing commands; and Output is provided to the user based on the longitudinal movement.

58. The system of claim 57, wherein the system does not require co-registration with another imaging technique such as angiography.

59. The system of claim 57, wherein the one or more step-adjustment commands indicate to the user a longitudinal movement speed.

60. The system of claim 59, wherein the longitudinal movement speed is in the range of 1 to 20 mm / sec.

61. The system according to any one of claims 57 to 60, wherein the processor is configured to receive the longitudinal movement speed from the user.

62. The system according to any one of claims 57 to 60, wherein the one or more step-adjustment instructions include one or more of the following: audio output, tactile output, visual output, or a combination thereof.

63. The system according to any one of claims 57 to 60, wherein the processor is further configured to: Collect IVUS images; and The IVUS images are annotated based on the longitudinal movement of the catheter body.

64. The system according to any one of claims 57 to 60, wherein the one or more markings are non-transmissive.

65. The system according to any one of claims 57 to 60, wherein the processor is further configured to detect error conditions.

66. The system of claim 65, wherein the error condition is one of the following: incorrect tag order, duplicate tags, missing tags, or inconsistency detection of the one or more tags.

67. A method for measuring the longitudinal distance between a series of images captured while manually moving an intravascular ultrasound (IVUS) catheter, the method comprising: Move the IVUS catheter manually along its longitudinal axis. While moving the IVUS catheter along its longitudinal axis in the proximal or distal direction, multiple images are captured using the IVUS catheter. The distance traveled by the IVUS duct is measured using an encoder that is not associated with a mechanical actuator or motor; Associate image or tissue features in the plurality of images with the distance traveled by the IVUS catheter; as well as The longitudinal length between images of the tissue features is determined based on the distance measured by the encoder.

68. The method of claim 67, wherein the method does not require co-registration with another imaging technique such as angiography.

69. The method according to any one of claims 67 to 68, wherein the encoder is optical.

70. The method according to any one of claims 67 to 68, wherein the encoder is inductive.

71. The method according to any one of claims 67 to 68, wherein the encoder is capacitive.

72. The method according to any one of claims 67 to 68, wherein the encoder comprises a mechanical wheel.

73. An intravascular ultrasound (IVUS) catheter system configured for detecting longitudinal position, the system comprising: The catheter body is configured to be placed within the lumen of a patient's blood vessel; One or more markers are provided along the catheter body; An encoder configured to measure the rate of movement of the one or more markers when the catheter body is moved longitudinally by hand; and Provides the ability to measure / report one or more output lengths to the user based on manual movement of the catheter body.

74. The system of claim 73, wherein the system does not require co-registration with another imaging technique such as angiography.

75. The system according to any one of claims 73 to 74, wherein the encoder is optical.

76. The system according to any one of claims 73 to 74, wherein the encoder is inductive.

77. The system according to any one of claims 73 to 74, wherein the encoder is capacitive.

78. The system according to any one of claims 73 to 74, wherein the encoder comprises a mechanical wheel.

79. The system according to any one of claims 73 to 74, comprising a linear variable differential transformer (LVDT).

80. The method according to any one of claims 1 to 25, 33 to 53 and 64 to 65, further comprising measuring the movement of the IVUS catheter with an encoder.

81. The method according to any one of claims 67 to 71, further comprising measuring the movement of the IVUS catheter with an encoder.

82. An intravascular ultrasound (IVUS) catheter system configured for detecting longitudinal position, the system comprising: A catheter body configured to be disposed within the lumen of a patient's blood vessel, the catheter body comprising: Imaging core, which is configured to capture multiple IVUS images; and One or more catheter electrodes; One or more external electrodes are disposed on the patient's skin; and At least one processor configured to electrically communicate with the one or more catheter electrodes and the one or more external electrodes, the at least one processor being configured to: The one or more catheter electrodes are instructed to generate one or more electrical signals; Receive one or more return electrical signals via the one or more external electrodes; and The in vivo location of the imaging core is determined based on the impedance of each of one or more returned electrical signals.

83. The system of claim 82, wherein the at least one processor is further configured to generate a three-dimensional map of the patient's vascular system based on the in vivo location of the imaging core and the plurality of IVUS images during the IVUS imaging procedure.

84. The system of claim 82, further comprising one or more patches configured to be placed on a patient's skin, wherein the one or more external electrodes are disposed on or in the one or more patches.

85. The system according to any one of claims 82 to 84, wherein the catheter body includes a catheter sheath, and wherein one or more catheter electrodes are disposed on the catheter sheath.

86. The system according to any one of claims 82 to 84, wherein the catheter body includes a catheter sheath, and wherein the one or more catheter electrodes are disposed within the catheter sheath.

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