System and method for placement of a vascular device

Abstract

A medical system includes an elongate vascular device having an optical fiber and a sensor module configured to detect pressure pulses at the skin surface resulting light pulses projected from a distal tip of the optical fiber within the vasculature of a patient. Logic of a system console processes pressure pulse data using photo-acoustic imaging techniques to obtain an image the vasculature. The processing also can include determining properties of the vasculature, such as a cross-sectional size of the vasculature, and determines therefrom a location of the distal tip.

Description

SYSTEM AND METHOD FOR PLACEMENT OF A VASCULAR DEVICEPRIORITY

[0001] This application claims the benefit of priority to U.S. Patent Application No. 63 / 568,391, filed March 21, 2024, which is incorporated by reference in its entirety into this application.BACKGROUND

[0002] The placement of the vascular device such as a central catheter commonly requires the distal tip to be placed at a specific location within the patient vasculature, such as the lower one-third of the superior vena cava or the cavoatrial junction, for example. Misplacement of the catheter tip may result in risk to the patient or reduced effectiveness of the catheter procedure. In some instances of misplacement, replacement of the catheter may be required resulting in further risk to the patient and increased medical expense. Ultrasound imaging can be utilized to provide guidance during placement of the placement of the vascular device. Photoacoustic imaging is a medical imaging technique that combines principles from both optics and acoustics to visualize structures within biological tissues with high resolution and contrast. One of the notable advantages of photoacoustic imaging is its ability to provide imaging depth and contrast comparable to general ultrasound imaging, while also offering the high resolution associated with optical imaging.

[0003] Disclosed herein are systems, devices, and methods that utilize photoacoustic imaging techniques to provide enhanced guidance during placement of the distal tip at a defined location within the patient vasculature.SUMMARY

[0004] Disclosed herein is a medical system that, according to some embodiments, an elongate medical device configured for insertion into a patient, where the elongate medical device includes an optical fiber extending along the elongate medical device, where a distal tip the optical fiber is configured to project a light pulse away from the optical fiber. A sensor module is configured for placement on a skin surface of the patient, where the sensor module includes a number of transducers configured to detect at the skin surface a pressure pulse resulting from the light pulse. A system module includes a console operatively coupled with the optical fiber and the sensor module. The console includes a processor and a memory havinglogic stored thereon that, when executed by the processor, performs operations of the system. The operations include (i) activating a light source of the console to define the light pulse; (ii) detecting by the sensor module the pressure pulse resulting from the light pulse; (iii) converting a pressure pulse signal from the sensor module into pressure pulse data; and (iv) processing the pressure pulse data to determine therefrom properties of anatomical elements within a proximity of the distal tip.

[0005] In some embodiments, activating the light source includes defining laser light pulses at one or more defined frequencies within the 20 kHz to 500 MHz, the laser light pulses having one or more wavelengths within the range of 700 nm and 1100 nm.

[0006] In some embodiments, determining the properties includes obtaining an image of the anatomical elements, and the operations further include depicting the image on a display of the system. In some embodiments, depicting the image includes indicating in the image a location of the distal tip in relation to the anatomical elements.

[0007] In some embodiments, processing the pressure pulse data includes determining a magnitude of the pressure pulse, and the pressure pulse state is defined at least partially by the magnitude. In some embodiments, processing the pressure pulse data includes determining a time delay of the pressure pulse with respect to the light pulse, and the pressure pulse state is defined at least partially by the time delay.

[0008] In some embodiments, activating the light source includes defining a series of light pulses at a defined frequency, and converting the pressure pulse signal includes converting a series of pressure pulses signals resulting from the series of light pulses into the pressure pulse data.

[0009] In some embodiments, the elongate medical device is configured for advancement along a vasculature of the patient, and the distal tip the optical fiber is configured to project the light pulse radially outward from the optical fiber.

[0010] In some embodiments, the operations further include continually processing the pressure pulse data during advancement of the elongate medical device along the vasculature such that the distal tip is displaced from a first location within the vasculature to a second location within the vasculature, where the vasculature includes a first cross-sectional size at thefirst location and a second cross-sectional size at the second location, and where the second cross-sectional size is larger than the first cross-sectional size.

[0011] In some embodiments, processing the pressure pulse data during advancement includes defining a first pressure pulse state when the distal tip is located at the first location, where the first pressure pulse state is defined at least partially by the first cross-sectional size, and defining a second pressure pulse state when the distal tip is located at the second location, where the second pressure pulse state is defined at least partially by the second cross-sectional size.

[0012] In some embodiments, the operations further include providing a notification to the user when the first pressure pulse state transitions to the second pressure pulse state, and in some embodiments, the notification includes depicting indicia on a display of the system, where the indicia indicates a state change from the first pressure pulse state to the second pressure pulse state.

[0013] In some embodiments, the system further includes a navigational sensor module coupled with the console that includes a plurality of sensor modules spaced away from each other on the patient, and the operations further include (i) detecting by each of the plurality of sensor modules the pressure pulse, (ii) converting pressure pulse signals from each of the plurality of sensor modules into the pressure pulse data; and (iii) continually processing the pressure pulse data utilizing navigation techniques to determine the location of the distal tip with respect to the navigational sensor module.

[0014] Also disclosed herein is a method that, according to some embodiments, includes (i) projecting a light pulse away from a distal tip of the optical fiber, the distal tip disposed within a patient; (ii) detecting a pressure pulse at a skin surface of the patient, the pressure pulse resulting from the light pulse; (iii) converting a pressure pulse signal into pressure pulse data for processing by logic executed by a processor; (iv) processing the pressure pulse data to define therefrom a pressure pulse state, where the pressure pulse state is related to a location of the distal tip.

[0015] In some embodiments of the method, processing the pressure pulse data includes determining a magnitude of the pressure pulse, and the pressure pulse state is defined at least partially by the magnitude. In some embodiments of the method, processing thepressure pulse data includes determining a time delay of the pressure pulse with respect to the light pulse, and the pressure pulse state is defined at least partially by the time delay.

[0016] In some embodiments of the method, project the light source includes projecting a series of light pulses at a defined frequency and converting the pressure pulse signal includes converting a series of pressure pulses signals resulting from the series of light pulses into the pressure pulse data.

[0017] In some embodiments of the method, the optical fiber is advanced along a vasculature of the patient, and the distal tip portion the optical fiber is configured to project the light pulse radially outward from the optical fiber.

[0018] In some embodiments, the method further includes continually processing the pressure pulse data during advancement of the optical fiber along the vasculature such that the distal tip is displaced from a first location within the vasculature to a second location within the vasculature, where the vasculature includes a first cross-sectional size at the first location and a second cross-sectional size at the second location, and where the second cross-sectional size is larger than the first cross-sectional size.

[0019] In some embodiments of the method, continually processing the pressure pulse data during advancement includes defining a first pressure pulse state when the distal tip is located at the first location, where the first pressure pulse state defined at least partially by the first cross-sectional size, and defining a second pressure pulse state when the distal tip is located at the second location, where the second pressure pulse state defined at least partially by the second cross-sectional size.

[0020] In some embodiments, the method further includes providing a notification to the user when the first pressure pulse state transitions to the second pressure pulse state.

[0021] In some embodiments, the method further includes (i) continually processing the pressure pulse data during insertion of the catheter into the patient such that the distal tip is displaced from a first depth to a second depth; (ii) defining a third pressure pulse state when the distal tip is disposed at the first depth; (iii) defining a fourth pressure pulse state when the distal tip is disposed at the second depth; and (iv) providing a notification to the user when the third pressure pulse state transitions to the fourth pressure pulse state.

[0022] In some embodiments of the method, the optical fiber is slidably disposed within a lumen of a catheter, and the method further comprises (i) continually processing the pressure pulse data during displacement of the catheter with respect to the optical fiber such that the distal tip is displaced from beyond a distal end of the catheter to within the lumen of the catheter; (ii) defining a fifth pressure pulse state when the distal tip is disposed beyond the distal end of the catheter; (iii) defining a sixth pressure pulse state when the distal tip is disposed within the lumen; and (iv) providing a notification to the user when the fifth pressure pulse state transitions to the sixth pressure pulse state indicating that the catheter covers the distal tip.

[0023] These and other features of the concepts provided herein will become more apparent to those of skill in the art in view of the accompanying drawings and following description, which describe particular embodiments of such concepts in greater detail.BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 illustrates a device tracking system that incorporates photo acoustic functionality, in accordance with some embodiments.

[0025] FIG. 2 illustrates a functional model of the system of FIG. 1 including exemplary photo-acoustic properties, in accordance with some embodiments.

[0026] FIG. 3 illustrates one exemplary implementation of the system of FIG. 1, in accordance with some embodiments.

[0027] FIG. 4 illustrates one other exemplary implementation of the system of FIG. 1, in accordance with some embodiments.

[0028] FIG. 5 is a block diagram of a method of providing guidance to a user during placement of a vascular device within a patient, in accordance with some embodiments.DESCRIPTION

[0029] Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment andoptionally combined with or substituted for features of any of a number of other embodiments disclosed herein.

[0030] Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. Labels such as “left,” “right,” “top,” “bottom,” “front,” “back,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.

[0031] The phrases “connected to,” “coupled with,” and “in communication with” refer to any form of interaction between two or more entities, including but not limited to mechanical, electrical, magnetic, electromagnetic, fluid, and thermal interaction. Two components may be coupled with each other even though they are not in direct contact with each other. For example, two components may be coupled with each other through an intermediate component.

[0032] The terms “proximal” and “distal” refer to opposite ends of a medical device, including the devices disclosed herein. As used herein, the proximal portion of a medical device is the portion nearest a practitioner during use, while the distal portion is the portion at the opposite end. For example, the distal end of medical device is defined as the end closest to the patient or furthest inserted into the patient during utilization of the medical device. The proximal end is the end opposite the distal end.

[0033] The term “logic” may be representative of hardware, firmware or software that is configured to perform one or more functions. As hardware, the term logic may refer to or include circuitry having data processing and / or storage functionality. Examples of such circuitry may include, but are not limited or restricted to, a hardware processor (e.g., microprocessor, one or more processor cores, a digital signal processor, a programmable gatearray, a microcontroller, an application specific integrated circuit “ASIC”, etc.), a semiconductor memory, or combinatorial elements.

[0034] Additionally, or in the alternative, the term logic may refer to or include software such as one or more processes, one or more instances, Application Programming Interface(s) (API), subroutine(s), function(s), applet(s), servlet(s), routine(s), source code, object code, shared library / dynamic link library (dll), or even one or more instructions. This software may be stored in any type of a suitable non-transitory storage medium, or transitory storage medium (e.g., electrical, optical, acoustical or other form of propagated signals such as carrier waves, infrared signals, or digital signals). Examples of a non-transitory storage medium may include, but are not limited or restricted to a programmable circuit; non-persistent storage such as volatile memory (e.g., any type of random access memory “RAM”); or persistent storage such as non-volatile memory (e.g., read-only memory “ROM”, power-backed RAM, flash memory, phase-change memory, etc.), a solid-state drive, hard disk drive, an optical disc drive, or a portable memory device. As firmware, the logic may be stored in persistent storage.

[0035] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art. References to approximations are made throughout this specification, such as by use of the term “substantially.” For each such reference, it is to be understood that, in some embodiments, the value, feature, or characteristic may be specified without approximation. For example, where qualifiers such as “about” and “substantially” are used, these terms include within their scope the qualified words in the absence of their qualifiers. For example, where the term “substantially straight” is recited with respect to a feature, it is understood that in further embodiments, the feature can have a precisely straight configuration.

[0036] Any methods disclosed herein include one or more steps or actions for performing the described method. The method steps and / or actions may be interchanged with one another. In other words, unless a specific order of steps or actions is required for proper operation of the embodiment, the order and / or use of specific steps and / or actions may be modified. Moreover, sub-routines or only a portion of a method described herein may be a separate method within the scope of this disclosure. Stated otherwise, some methods may include only a portion of the steps described in a more detailed method. Additionally, all embodiments disclosed herein are combinable and / or interchangeable unless stated otherwiseor such combination or interchange would be contrary to the stated operability of either embodiment.

[0037] Photoacoustic imaging is a medical imaging technique that combines principles from both optics and acoustics to visualize structures within biological tissues with high resolution and contrast. This imaging modality relies on the photoacoustic effect, where short pulses of light e.g., (laser light) are directed into biological tissues. Upon absorption of these light pulses, the tissue undergoes rapid thermal expansion, generating ultrasound waves or acoustic signals. These signals are then detected by ultrasound transducers at the skin surface. The detected signals are subsequently processed to reconstruct detailed images that reveal both anatomical and functional information, including properties of anatomical elements beneath the skin surface. One of the notable advantages of photoacoustic imaging is its ability to provide imaging depth and contrast comparable to general ultrasound imaging, while also offering the high resolution associated with optical imaging. The choice of laser wavelength can be tailored to target specific subcutaneous structures.

[0038] Photoacoustic imaging utilizes a range of wavelengths of light, and wavelength may be chosen in accordance with desired imaging depth and specificity. An optimal wavelength may be partially based optical absorption characteristics of the target structures within the tissue. Common wave lengths include Near-Infrared (NIR) Range (700 nm - 1100 nm) and Extended Near-Infrared (NIR-II) Range (1100 nm - 1350 nm).

[0039] The sound wave frequency range in photoacoustic imaging can vary depending on several factors, including the characteristics of the laser pulse used for excitation, the properties of the imaged tissue, and the detection capabilities of the ultrasound transducer. Generally, the frequency content of photoacoustic signals spans a wide range, typically from a few hertz to several megahertz. The frequency of photoacoustic signals can vary with imaging depth. Higher frequencies may dominate in superficial imaging, while lower frequencies may be more prevalent in deeper tissue imaging. Sub-megahertz frequencies may be advantageous for analyzing larger structures and features in the imaged tissue, and megahertz be advantageous for analyzing smaller structures and finer details within the tissue. The ultrasound transducers are chosen to ensure that the range of frequencies can be effectively detected.

[0040] The frequency spectrum of the photoacoustic signals can be used to extract data about the size and composition of the anatomical structures. In photoacoustic imaging, thesound wave frequency is defined by the characteristics of the acoustic signals generated by the photoacoustic effect. The frequency spectrum of the photoacoustic signals is often analyzed using signal processing techniques, such as Fourier analysis. This decomposition of the signals into their constituent frequencies so that information about the size, composition, and depth of the anatomical structures can be extracted from the photoacoustic signals.

[0041] Disclosed herein are systems and methods that utilize the photo-acoustic effect described above to enable clinician to accurately place medical devices within the patient body. The medical devices can be any medical device configured for placement within the body at any location within the body. The embodiments described below are just some exemplary none-limiting implementations of the photo-acoustic effect of many more implementation that could be contemplated by one of ordinary skill.

[0042] FIG. 1 illustrates a device tracking system (system) 100 that incorporates at least partially the photo-acoustic processes described above, in accordance with some embodiments. The system 100 is generally configured to enable a clinician to place a distal end of an elongate medical device (e.g., a catheter) at a defined location within a vasculature of the patient 50. The system 100 generally includes the elongate medical device (device) 150 and a sensor module 170, each of which are operatively coupled with a system module 110 and having a console 115. In the illustrated embodiment, the sensor module 170 and the system module 110 are separate modules operatively coupled to each other. In other embodiments, the sensor module 170 and the system module 110 may be combined into a single module, e.g., the console 115 and other components of the system module 110 may be incorporated into the sensor module 170.

[0043] The device 150 may include any elongate device configured for insertion into the patient 50 such as through the skin or via a body orifice, e.g., throat, anal canal, or urethra. As described herein, the device 150 includes a vascular device, such as a stylet, a guidewire or a catheter, for example. An optical fiber 160 extends along the device 150. As illustrated, a distal tip 161 of the optical fiber 160 may be positioned adjacent a distal end 151 of the device 150. In some embodiment, distal tip 161 of the optical fiber 160 may extend distally away from distal end 151. In some embodiments, the optical fiber 160 may be embedded into the device 150 such as embedded within the wall of catheter, for example. In other examples, the optical fiber 160 may be slidably coupled with the medical device 150 such that the optical fiber 160 is longitudinally positionable with respect to the device 150. According to one embodiment,the optical fiber 160 may be slidably disposed within a lumen of the medical device 150, e.g., a lumen of the catheter. By way of one example, the optical fiber 160 may be coupled with or incorporated into a guidewire configured for advancement along the vascular and the guidewire may be disposed within the lumen of the catheter. As such, the distal tip 161 of the optical fiber 160 may be positionable with respect to the distal end 151 of the device 150, e.g., disposed within the lumen or extended beyond the distal end 151.

[0044] The optical fiber 160 may be coupled with an optical cable 163 via an optical connector 164, where the optical connector 164 enables the optical fiber 160 to be selectively coupled with and decoupled from the optical cable 163. The optical fiber 160 is optically coupled with the console 115 via the optical cable 163 and the optical cable 163 may be physically (e.g., permanently) attached to the system module 110. The device 150 and / or the optical fiber 160 may be configured for single use or multi-use.

[0045] The sensor module 170 is configured for placement on the patient 50 such that the sensor module 170 is sonically coupled with the skin surface 51. The sensor module 170 is generally configured to detect pressure pulses 174 (i.e., sound waves including ultrasonic waves) at a skin surface 51 of the patient 50. In some embodiments, the sensor module 170 may detect the pressure pulses at the skin surface 51. In some embodiments, the sensor module 170 may include or be composed of an ultrasound probe. The sensor module 170 includes a number of transducers 172 (e.g., piezo-electric ultrasound transducers) disposed along a patient contact surface 173 of the sensor module 170. The transducers 172 may define a onedimensional or two-dimensional array extending across the patient contact surface 173. The sensor module 170 is operatively coupled with the console 115 via an electrical cable 176.

[0046] The console 115 includes components that generally define the operation of the system 100. It can be appreciated that the console 115 can take one of a variety of forms. A processor 116 and memory 120 (including a non-transitory computer-readable medium) may be combined in a single device, such as an EEPROM, for example. The processor 116 and memory 120 control system function during operation of the system module 110. The memory 220 includes pulse control logic 121 and pulse processing logic 122. A digital controller / analog interface 175 is also included with the console 115 and is in communication with the processor 210 and other system components. The digital controller / analog interface 175 is coupled with the sensor module 170 via the electrical cable 176 and converts pressure pulse signals (i.e., electrical signals from the transducers 172) into pressure pulse data for processing by the pulseprocessing logic 123. An optical interface 162 provides operatively coupling between the optical fiber 150 and a light source 161. The light source 161 is coupled with the digital controller / analog interface 175 so that the pulse control logic 121 can control the operation of the light source 161.

[0047] The light 165 may include a preferred wavelength or multiple preferred wavelengths, such as wavelengths between 700 nm and 1100 nm. In some embodiments, the light source 161 may include a laser that defines the wavelength(s) of the light 165, such as laser diode, for example. Such a laser diode may include a semiconductor device similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. In other embodiments, the optical fiber 160 may include a fiber laser that defines the wavelength(s) of the light 165, where the fiber laser is excited by the light source 161. One example of a fiber laser is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and holmium.

[0048] The console 115 can further include a plurality of ports 117 for connection with optional components 119 including a printer, storage media, keyboard, etc. The ports 117 in one embodiment may include USB ports, though other port types or a combination of port types can be used for this and the other interface connections described herein. In certain embodiments, the console 115 may include a wireless module 118 to enable wireless communication over a network. The console 115 may also include a display 112 (e.g., a graphical user interface) configured to provide notification to the user. The display 112 may also be configured to receive input from the user.

[0049] A power connection 131 may be included with the console 115 to enable operable connection to an external power supply 132. An internal power supply 133 (e.g., a battery) can also be employed, either with or exclusive of the external power supply 253. Power management circuitry 130 is included to regulate power use and distribution.

[0050] The pulse control logic 121 is generally configured to control the optical operation of the optical fiber 160. The optical fiber 160 is configured to receive the light 165 from the light source 161, propagate the light 165 along the optical fiber 160 to the distal tip 161, and project the light 165 outward (including radially outward) from the optical fiber 160. During use, the light 165 is projected onto anatomical elements of the patient 50. According toone implementation (i.e., the illustrated implementation) the light 165 is projected through the blood 61 of the blood vessel 60 onto and through the blood vessel wall 62. Energy from the light 165 causes the blood vessel wall 62 and other surrounding anatomical elements according to expand or otherwise change shape, e.g., due to heating as a result of the light 165. The expansion of the blood vessel wall 62 and surrounding anatomical elements defines a localized pressure change within the patient 50. According to the illustrated implementation, the light source 161 generates a light pulse that propagates along the optical fiber 160 projects onto the blood vessel wall 62 and surrounding anatomical elements. The blood vessel wall 62 and surrounding anatomical elements expand in response to the light pulse which generates a pressure pulse 174. The pressure pulse 174 propagates to the skin surface 51 where the sensor module 170 detects the pressure pulse 174 via the transducers 712. The pulse processing logic 122 receives pressure pulse data from the digital controller / analog interface 175 and processes the pressure pulse data.

[0051] The pulse control logic 121 may define a series of light pulses in accordance with a defined pulse rate or frequency. In some embodiments, the frequency may include a frequency range of 20 kilohertz to 500 megahertz or more narrowly a range of 2 megahertz to 18 megahertz The pulse control logic 121 may also define a pulse duration, i.e., an “on” time of each pulse. More specifically, the pulse control logic 121 may define a duty cycle of the light pulses, where the duty cycle is the percent “on” time for the light pulses. In some embodiments, the duty cycle may be between 5 and 50 percent. When the pulse control logic 121 defines light pulses at the defined frequency or frequencies, the blood vessel wall 62 vibrates at the defined frequency and generates sound waves that propagate to the skin surface 51. The pulse processing logic 122 analyzes the sound waves via photo-acoustic techniques to obtain an image of the blood vessel 60 and the surround anatomical elements (e.g., the vasculature) based on the sound waves (pressure pulses). The pulse processing logic 122 may also determine from the sound waves properties of the blood vessel 60 as further described below.

[0052] FIG. 2 illustrates a non-limiting model of the exemplary photo-acoustic functionalities of the system 100, according to some embodiments. The blood vessel 60 is shown, where a size of the blood vessel 60 includes a first diameter 206A, a second diameter 206B, and third diameter 206C. The second diameter 206B is greater than the first diameter 206A and the third diameter 206C is greater than the second diameter 206B. The optical fiber160 is shown at three positions such that the distal tip 161 having the light 165 projected radially outward therefrom is disposed at a first position 205A, a second position 205B and a third position 205B in accordance with the first diameter 206A, the second diameter 206B, and the third diameter 206C. The sensor module 170, in contact with skin surface 51, is also positioned in alignment with the first position 205A, a second position 205B and a third position 205B of the distal tip 161. At each of the first, second, and third positions 205A-205C, the blood vessel 260 is located at a first, second, and third depth 207A-207C, respectively from the skin surface 51.

[0053] The light 165 travels through the blood 61 within the blood vessel 60 between the optical fiber 160 and the blood vessel wall 62, where the distance between the optical fiber 160 and the blood vessel wall 62 is related to the diameter of the blood vessel 60. Accordingly, in the illustrated model, the light 165 travels through the blood 61 a distance 209A at the first location 205A, a distance 209B at the second location 205B, and a distance 209C at the third location 205C. In some embodiments, the distance the light 165 travels through the blood 61 may affect (e.g., reduce) the energy of the light 165 received by the blood vessel wall 62 due to absorption of light energy by the blood 61. In more general terms, the diameter of the blood vessel 60 may affect the pressure pulse resulting from the light 165.

[0054] During operation, the light 165 causes the blood vessel wall 62 to change shape (e.g., expand or move) in response to the light 165 projected thereon due to a temperature change of the blood vessel wall 62 or other tissue in the proximity of the light projection. The shape change causes a pressure pulse (i.e., a sound wave) to propagate through bodily tissue from the blood vessel wall 62 to the skin surface 51 at the speed of sound through the tissue. At each of the first, second, and third positions 205A-205C, the light 165 defines a corresponding first, second, and third pressure pulses 208A-208C, respectively. The first pressure pulse 208A travels the distance 207A, the second pressure pulse 208B travels the distance 207B, and the third pressure pulse 208C travels the distance 207C to the skin surface 51.

[0055] FIG. 2 further illustrates graphs 202A-202C that depict a various parameters of the pressure pulses 208A-208C, respectively, where the various parameters define a pressure pulse state. Each graph shows a light pulse 210 as projected from the optical fiber 160 and a resulting pressure pulse state 211A-211C as detected by the sensor module 170. Each graph includes an x-axis representing time and y-axis representing a magnitude (intensity) of thepressure pulse. In the illustrated model, each pressure pulse state 211A-211C represents the parameters of the pressure pulses 208A-208C. Again, in the exemplary non-limiting model, each pressure pulse state 211 A-211C may include a corresponding magnitude 212A-212C and a corresponding time delay 213A-213C. Of course, other parameters of the pressure pulse are considered and may be included, such as a width of the pressure pulse a detected by different transducers 172 positioned at different locations, variations in the magnitude or time delay based on different wavelengths of the light 165 or different pulse frequencies, for example. Indeed, the parameters of the pressure pulse (sound wave) may include any subset of parameters typically included with photo-acoustic imaging

[0056] Graph 202A shows a magnitude 212A of the pressure pulse state 211 A that corresponds to or is at least partially defined by the diameter 206A and the graph 202C shows a magnitude 212C of the pressure pulse state 211C that corresponds to or is at least partially defined by the diameter 206C. As the diameter 206C is greater that the diameter 206A, the magnitude 212A may be greater than the magnitude 212C. In this way, the pulse processing logic 122 may detect difference in diameter between the diameter 206 A and the diameter 206C. More specifically, the pulse processing logic 122 determine a pressure pulse state in accordance with the diameter 206A that is different than a pressure pulse state in accordance with the diameter 206C.

[0057] Similarly, the graph 202A shows a time delay 213 A of the pressure pulse response 211 A that corresponds to or is at least partially defined by the distance 207A and the graph 202B shows a time delay 213B of the pressure pulse response 211C that corresponds to or is at least partially defined by the distance 207B. As the distance 207B is greater that the distance 207A, the time delay 213B may be greater than the time delay 213 A. In this way, the pulse processing logic 122 may detect difference in distance between the distance 207A and the distance 207B. More specifically, the pulse processing logic 122 determine a pressure pulse state in accordance with the distance 207A that is different than a pressure pulse state in accordance with the distance 207B.

[0058] By way of one example of use, the user may advance the optical fiber 160 along the blood vessel 60 such that the distal tip 161 is displaced from the position 205 A to the position 205B. As the distal tip 161 is displaced from the position 205 A to the position 205B, the magnitude of the pressure pulse state transitions (e.g., decreases) from the magnitude 212A to the magnitude 212B as a result of the increase in diameter from the diameter 206 A to thediameter 206B. Further as the distal tip 161 is displaced from the position 205A to the position 205B, the time delay of the pressure pulse state transitions (e.g., increases) from the time delay 213 A to the time delay 213B as a result of the increase in depth from the depth 207A to the depth 207B.

[0059] By way of another example of use, the user may advance the optical fiber 160 along the blood vessel 60 such that the distal tip 161 is displaced from the position 205B to the position 205C resulting in a change of the pressure pulse state. As the distal tip 161 is displaced from the position 205B to the position 205C, the magnitude of the pressure pulse state transitions (e.g., decreases) from the magnitude 212B to the magnitude 212C as a result of the increase in diameter from the diameter 206B to the diameter 206C. Further as the distal tip 161 is displaced from the position 205A to the position 205C, the time delay of the pressure pulse response transitions (e.g., decreases) from the time delay 213B to the time delay 213C as a result of the decrease in depth from the depth 207B to the depth 207C. In an instance (not shown) where the sensor module 170 is positioned laterally offset from the distal tip 161, the time delay may be related to the total distance between the sensor module 170 and the distal tip 161 which may include a depth component and a lateral offset component.

[0060] FIG. 3 illustrates one exemplary implementation (e.g., an instance of use) of the system 100 in use with a patient 50, in accordance with some embodiments. The system 100 is generally configured to enable a clinician to place the distal end 151 of device 150 at a defined location within a vasculature of the patient 50. FIG. 3 further illustrates various exemplary elements of the patient 50. A heart 360 of the patient 50 includes a right atrium 361. A venous vasculature 370 includes a brachial vein 371, a subclavian vein 372, and a superior vena cava373. The superior vena cava 373 couples with the right atrium 361 at the cavoatrial junction374.

[0061] The device 150 is configured for insertion within the venous vasculature 70 and may include any suitable medical device, such as a catheter, a stylet or guidewire, for example. In the illustrated implementation, the device 150 is inserted into the brachial vein 371 at the insertion site 351. The device 150 is advanced along the brachial vein 371, the subclavian vein 372, and the superior vena cava 373. During advancement of the device 150, the distal end 151 (including the distal tip 161) is displaced from a first location 301 within the superior vena cava 373 to a second location 302 within the right atrium 61. As such, the distal end 151 is displaced across the cavoatrial junction 374 as the distal end 151 is displaced between the first location301 the second location 302. As is known, the right atrium 361 includes a greater cross- sectional area or diameter than the superior vena cava 373. As such, the cavoatrial junction 374 defines a transition between the cross-sectional area of the superior vena cava 373 and the cross-sectional area of the right atrium 361.

[0062] The sensor module 170 is placed on the skin surface 51 of the patient 50 to be located over the cavoatrial junction 374. The size and shape of the sensor module 170 may vary in relation to the size and shape shown. For example, the sensor module 170 may be configured to cover larger portion of the patient 50. The sensor module 170 is illustrated as transparent to allow details beneath the sensor module 170 to be shown.

[0063] During advancement, the light 165 distal tip 161 is projected away from the distal tip 161 to excite (i.e., cause to vibrate) the body tissue in the proximity of the distal tip 161 such that the anatomical elements can be visualized as described. More specifically, pressure pulses (sound waves) are detected by the sensor module 170 and the pressure pulse data is processed by the pulse processing logic 122 to create an image 308 of the anatomical elements including the vasculature 370 that is depicted on the display 112. In some embodiments, the pulse processing logic 122 may determine a location of the distal tip 161 by analyzing the vibration intensity (e.g., magnitude of the sound waves) since the vibration intensity can decrease with distance from the distal tip 165. As such, the image 308 may visually indicate the location 309 of the distal tip 161 as the device 150 is advanced along the vasculature 370. In this way, the user may visually track the location of the distal end 151 of the device 150 during advancement.

[0064] The pulse processing logic 122 may also cause a graph 310 to be depicted on the display 112, where the graph 310 indicates the pressure pulse state as described above in relation to FIG. 2. The graph 112 indicates a (i) first pressure pulse state 311 consistent with the distal end 151 located at the first position 301 and (ii) a second pressure pulse state 312 consistent with the distal end 151 located at the second position 302. During advancement of the device 150, the graph 112 transitions from the first pressure pulse state 311 to the second pressure pulse state 312 as the distal end 151 is displaced across the cavoatrial junction 374 from the superior vena cava 373 to the right atrium 361. Similarly, during retraction of the device 150, the graph 112 transitions from the second pressure pulse state 312 to the first pressure pulse state 312 as the distal end 151 is displaced across the cavoatrial junction 374 from the right atrium 361 to the superior vena cava 373. As such, the user can determine theposition of the distal end 151 with respect to the cavoatrial junction 374 by distally advancing the device 150 with respect to the insertion site 351 and / or proximally retracting the device 150 with respect to the insertion site 351 while observing the graph 112 and noting the transitioning of the graph 112 between the first pressure pulse state 311 and the second pressure pulse state 312.

[0065] As described above, (although not specifically shown) the device 150 may include a catheter having the optical fiber 160 slidably disposed within the lumen of the catheter. During advancement of the catheter (the device 150 including the optical fiber 160) and positioning of the distal tip 161, the distal tip 161 may be extended distally away for the distal end 151 of the catheter so that the light 165 may be projected radially away from the optical fiber 160. Once the distal tip 161 is finally positioned as described above, the user may distally displace the catheter with respect to the optical fiber 160 so as to finally position the distal end 151 of the catheter. As the distal end 151 of the catheter is distally displaced with respect to the optical fiber 160, the catheter covers the distal tip 161, thereby inhibiting projection of the light 165 onto the blood vessel wall. As such, the pressure pulse state response is affected which may include a decrease in the magnitude of the pressure pulse state. In this way, the user may know that the distal end 151 is positioned at the same location as the distal tip 161.

[0066] FIG. 4 illustrates an exemplary device tracking system 400 in use with a patient 50 that may, in some respects, resemble the components and functions of the system 100, in accordance with some embodiments. The system 400 is generally configured to enable a clinician to track the location of the distal end 151 of device 150 (which includes the distal tip 161) during advancement of the device 150 along the vasculature of the patient 50. FIG. 4 further illustrates various exemplary elements of the patient 50 similar to FIG. 3. In the illustrated embodiment, the device 150 is inserted into the brachial vein 371 at the insertion site 351. The device 150 including the distal tip 161 is advanced along the brachial vein 371, the subclavian vein 372, and the superior vena cava 373 to the right atrium 361.

[0067] A navigation sensor module 470 is placed on the skin surface 51 of the patient 50. The navigation sensor module 470 includes a number of sensor modules spaced away from each other, such as the sensor modules 470A-470C, for example. Each of the sensor modules 470A-470C may in some respects resemble the components and functionality of the sensor module 170. The navigation sensor module 470 is illustrated as transparent to allow detailsbeneath the navigation sensor module 470 to be shown. In accordance with the photo acoustic functionalities and parameters illustrated in FIG. 2 and described therewith, the device tracking system 400 is configured to determine the location of the distal tip 161 with respect to the navigation sensor module 470 and track the location of the distal tip 161 during advancement of the device 150 along the vasculature or at any other location within the patient 50 within a detectable proximity of the navigation sensor module 470.

[0068] The pulse processing logic 122 may process the pressure pulse data as similarly described above to determine a distance (through the patient) between distal tip 161 and each of the sensor modules 470A-470C. The pulse processing logic 122 may further process the pressure pulse data utilizing navigational techniques (e.g., triangulated navigational techniques) to determine the location of the distal tip 161 with respect to the navigation sensor module 470. As the navigation sensor module 470 may be located on the patient 50 with respect to known anatomical landmarks, the location of the distal tip 151 with respect to the navigation sensor module 470 may be related to the location of the distal tip 151with respect to one or more anatomical elements of the patient 50, such as the heart, for example, as the device 150 is advanced along the vasculature.

[0069] An image depicted on the display 112 may include a representation of the navigation sensor module 471 and a location (or track) 451 of the distal tip 161 shown in relation to the representation of the navigation sensor module 471. As such, the user may determine the location of the distal tip 161 with respect to the navigation sensor module 470 by observing the image on the distal 112.

[0070] FIG. 5 is a block diagram of a method 500 that includes all or any subset of the following steps, operations, actions, or process, according to some embodiments. The method 500 utilizes components of the device tracking system as performed by logic of the device tracking system. The method 500 includes projecting a light pulse away from a distal tip of the optical fiber, where the distal tip is disposed within a patient (block 510). The method 500 further includes detecting a pressure pulse at a skin surface of the patient, where the pressure pulse is a result of the light pulse (block 520)

[0071] The method 500 further includes converting a pressure pulse signal into pressure pulse data for processing by logic (block 530). In some embodiments of the method 500, projecting the light includes projecting a series of light pulses, and converting the pressurepulse signal includes converting a series of pressure pulses signals resulting from the series of light pulses into the pressure pulse data.

[0072] The method 500 further includes processing the pressure pulse data to define therefrom a pressure pulse state, where the pressure pulse state is related to a location of the distal tip (block 540). In some embodiments of the method 500, processing the pressure pulse data includes determining a magnitude of the pressure pulse, and the pressure pulse state is defined at least partially by the magnitude. In some embodiments of the method 500, processing the pressure pulse data includes determining a time delay of the pressure pulse with respect to the light pulse, and the pressure pulse state is defined at least partially by the time delay.

[0073] In some embodiments of the method 500, the optical fiber is advanced along a vasculature of the patient, and the distal tip portion the optical fiber is configured to project the light pulse radially outward from the optical fiber.

[0074] In some embodiments, the method 500 further includes continually processing the pressure pulse data during advancement of the optical fiber along the vasculature, such that the distal tip is displaced from a first location within the vasculature to a second location within the vasculature, where the vasculature includes a first cross-sectional size at the first location and a second cross-sectional size at the second location, and where the second cross-sectional size is larger than the first cross-sectional size.

[0075] In some embodiments of the method 500, continually processing the pressure pulse data during advancement includes defining a first pressure pulse state when the distal tip is located at the first location, where the first pressure pulse state defined at least partially by the first cross-sectional size, and defining a second pressure pulse state when the distal tip is located at the second location, where the second pressure pulse state defined at least partially by the second cross-sectional size.

[0076] In some embodiments, the method 500 further includes providing a notification to the user when the pressure pulse state transitions from first pressure pulse state transitions to the second pressure pulse state (block 550).

[0077] In some embodiments, the method 500 further includes (i) continually processing the pressure pulse data during insertion of the catheter into the patient such that thedistal tip is displaced from a first depth to a second depth; (ii) defining a third pressure pulse state when the distal tip is disposed at the first depth; (iii) defining a fourth pressure pulse state when the distal tip is disposed at the second depth; and (iv) providing a notification to the user when the third pressure pulse state transitions to the fourth pressure pulse state.

[0078] In some embodiments of the method 500, the optical fiber is slidably disposed within a lumen of a catheter, and the method further comprises (i) continually processing the pressure pulse data during displacement of the catheter with respect to the optical fiber such that the distal tip is displaced from beyond a distal end of the catheter to within the lumen of the catheter; (ii) defining a fifth pressure pulse state when the distal tip is disposed beyond the distal end of the catheter; (iii) defining a sixth pressure pulse state when the distal tip is disposed within the lumen; and (iv) providing a notification to the user when the fifth pressure pulse state transitions to the sixth pressure pulse state indicating that the catheter covers the distal tip.

[0079] While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and / or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and / or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein.

Claims

CLAIMSWhat is claimed is:

1. A medical system, comprising: an elongate medical device configured for insertion into a patient, the elongate medical device comprising an optical fiber extending along the elongate medical device, wherein a distal tip the optical fiber is configured to project light pulses away from the optical fiber; a sensor module configured for placement on a skin surface of the patient, the sensor module including a number of transducers configured to detect at the skin surface pressure pulses resulting from the light pulses; a system module including a console operatively coupled with the optical fiber and the sensor module, the console including a processor and a memory having logic stored thereon that, when executed by the processor, performs operations that include: activating a light source of the console to define the light pulses; detecting by the sensor module the pressure pulses resulting from the light pulses; converting a pressure pulse signal from the sensor module into pressure pulse data; and processing the pressure pulse data to determine therefrom properties of anatomical elements within a proximity of the distal tip.

2. The system according to claim 1, wherein: activating the light source includes defining laser light pulses at one or more defined frequencies within the 20 kilohertz to 500 megahertz, the laser light pulses having one or more wavelengths within the range of 700 nm and 1100 nm.

3. The system according to claim 1 or claim 2, wherein: determining the properties includes obtaining an image of the anatomical elements, and the operations further include depicting the image on a display of the system.

4. The system according to claim 3, wherein depicting the image includes indicating in the image a location of the distal tip in relation to the anatomical elements.

5. The system according to any of the preceding claims, wherein: the elongate medical device is configured for advancement along a vasculature of the patient, and the distal tip the optical fiber is configured to project the light pulses radially outward from the optical fiber.

6. The system according to claim 5, wherein: processing the pressure pulse data includes defining therefrom a pressure pulse state, and the pressure pulse state is related to a location of the distal tip within the within the vasculature.

7. The system according to claim 6, wherein: processing the pressure pulse data includes determining a magnitude of the pressure pulses, and the pressure pulse state is defined at least partially by the magnitude.

8. The system according to claim 6 or claim 7, wherein: processing the pressure pulse data includes determining a time delay of the pressure pulses with respect to the light pulses, and the pressure pulse state is defined at least partially by the time delay.

9. The system according to claim 8, wherein: the operations further include continually processing the pressure pulse data during advancement of the elongate medical device along the vasculature such that the distal tip is displaced from a first location within the vasculature to a second location within the vasculature, the vasculature includes a first cross-sectional size at the first location and a second cross-sectional size at the second location, and the second cross-sectional size is larger than the first cross-sectional size.

10. The system according to claim 9, wherein: processing the pressure pulse data during advancement includes defining a first pressure pulse state when the distal tip is located at the first location, the first pressure pulse state defined at least partially by the first cross-sectional size, and defining a second pressure pulse state when the distal tip is located at the second location, the second pressure pulse state defined at least partially by the second cross-sectional size.

11. The system according to claim 10, wherein the operations further include providing a notification to the user when the first pressure pulse state transitions to the second pressure pulse state.

12. The system according to claim 11, wherein the notification includes depicting indicia on the display, the indicia indicating a state change from the first pressure pulse state to the second pressure pulse state.

13. The system according to any of claims 5-12, further including a navigational sensor module coupled with the console that includes a plurality of the sensor modules spaced away from each other on the patient, and the operations further include: detecting by each of the plurality of sensor modules the pressure pulses resulting from the light pulses, converting pressure pulse signals from each of the plurality of sensor modules into the pressure pulse data; and continually processing the pressure pulse data during advancement of the elongate medical device along the vasculature utilizing navigation techniques to determine the location of the distal tip with respect to the navigational sensor module.

14. A method, comprising: projecting a light pulse away from a distal tip of the optical fiber, the distal tip disposed within a patient; detecting a pressure pulse at a skin surface of the patient, the pressure pulse resulting from the light pulse;converting a pressure pulse signal into pressure pulse data for processing by logic executed by a processor; and processing the pressure pulse data to define therefrom a pressure pulse state, wherein the pressure pulse state is related to a location of the distal tip.

15. The method according to claim 14, wherein: processing the pressure pulse data includes determining a magnitude of the pressure pulse, and the pressure pulse state is defined at least partially by the magnitude.

16. The method according to claim 14 or claim 15, wherein: processing the pressure pulse data includes determining a time delay of the pressure pulse with respect to the light pulse, and the pressure pulse state is defined at least partially by the time delay.

17. The method according to any of claims 14-16, wherein: projecting the light pulse includes projecting a series of light pulses, and converting the pressure pulse signal includes converting a series of pressure pulses signals resulting from the series of light pulses into the pressure pulse data.

18. The method according to any of claims 14-17, wherein: the optical fiber is advanced along a vasculature of the patient, and the distal tip portion the optical fiber is configured to project the light pulse radially outward from the optical fiber.

19. The method according to claim 18, further comprising continually processing the pressure pulse data during advancement of the optical fiber along the vasculature such that the distal tip is displaced from a first location within the vasculature to a second location within the vasculature, wherein: the vasculature includes a first cross-sectional size at the first location and a second cross-sectional size at the second location, and the second cross-sectional size is larger than the first cross-sectional size.

20. The method according to claim 19, wherein: continually processing the pressure pulse data during advancement includes defining a first pressure pulse state when the distal tip is located at the first location, the first pressure pulse state defined at least partially by the first cross-sectional size, and defining a second pressure pulse state when the distal tip is located at the second location, the second pressure pulse state defined at least partially by the second cross-sectional size.

21. The method according to claim 20, further comprising providing a notificationser when the first pressure pulse state transitions to the second pressure pulse state.

22. The method according to any of claims 14-21, further comprising: continually processing the pressure pulse data during insertion of the catheter into the patient such that the distal tip is displaced from a first depth to a second depth; defining a third pressure pulse state when the distal tip is disposed at the first depth; defining a fourth pressure pulse state when the distal tip is disposed at the second depth; and providing a notification to the user when the third pressure pulse state transitions to the fourth pressure pulse state.

23. The method according to any of claims 14-22, wherein: the optical fiber is slidably disposed within a lumen of a catheter, and the method further comprises: continually processing the pressure pulse data during displacement of the catheter with respect to the optical fiber such that the distal tip is displaced from beyond a distal end of the catheter to within the lumen of the catheter; defining a fifth pressure pulse state when the distal tip is disposed beyond the distal end of the catheter; defining a sixth pressure pulse state when the distal tip is disposed within the lumen; andproviding a notification to the user when the fifth pressure pulse state transitions to the sixth pressure pulse state indicating that the catheter covers the distal tip.

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