Shape sensing systems and methods for medical devices

Abstract

Shape sensing systems and methods for medical devices. The shape sensing system may include a medical device, an optical interrogator, a console, and a display screen. A medical device may include an integrated fiber optic stylet having a fiber Bragg grating ("FBG") sensor along at least a distal portion thereof. The optical interrogator may be configured to send an input optical signal into the fiber optic stylet and receive an optical signal reflected by the FBG sensor therefrom. The console may be configured to convert the reflected optical signal into drawable data to display a graph thereof on the display screen. The plot may include a curvature-to-time plot of each of the FBG sensors selected in the distal end portion of the fiber optic stylet for identifying a significant change in strain of the fiber optic stylet when the tip of the medical device is advanced into the superior vena cava of the patient.

Description

[0001] Divisional Information

[0002] This application is a divisional application of the patent application with application number 202010771128.3, titled "Shape Sensing System and Method for Medical Devices", filed on August 3, 2020.

[0003] Priority

[0004] This application claims the priority benefit of U.S. Provisional Application No. 62 / 885,702, filed on August 12, 2019, the entire content of which is incorporated herein by reference. Technical Field

[0005] This application is related to medical devices, and more particularly to a shape sensing system and method for medical devices. Background Art

[0006] Sometimes, the tip of a peripherally inserted central catheter ("PICC") or a central venous catheter ("CVC") may move and displace from an ideal position in a patient's superior vena cava ("SVC"). Clinicians who suspect that such a PICC or CVC has shifted typically check for displacement by means of a chest X-ray and, if necessary, replace the PICC or CVC. However, X-rays expose the patient to ionizing radiation. Accordingly, there is a need for clinicians to easily and safely check whether the PICC and CVC have shifted in order to replace them if necessary.

[0007] Disclosed herein are a shape sensing system and method for medical devices that solve the above problems. Summary of the Invention

[0008] The present disclosure relates to a shape sensing system for a medical device, which in some embodiments includes a medical device, an optical interrogator, a console, and a display screen. The medical device includes a body of implementation that contains optical fibers, where the optical fibers are composed of a plurality of fiber Bragg grating ("FBG") sensors along at least a distal portion of the optical fibers. As will be mainly discussed throughout this disclosure, one embodiment of the body of implementation is a fiber optic integrated stylet. However, other embodiments of the body of implementation include, but are not limited to, an integrated fiber optic guidewire or an integrated fiber optic catheter. The optical interrogator is configured to send an input optical signal into the fiber optic stylet and receive the optical signal reflected by the FBG sensors from the fiber optic stylet. The console includes a memory and one or more processors configured to convert the optical signal reflected by the FBG sensors from the fiber optic stylet into plottable data by means of various optical signal converter logics, which may include one or more algorithms. The display screen is configured to display any of a plurality of graphs of the plottable data. The plurality of graphs at least includes a graph of the curvature of each of the selected FBG sensors in the distal portion of the fiber optic stylet versus time, for identifying a significant change in the strain of the fiber optic stylet at the moment when the tip of the medical device is pushed into the patient's SVC.

[0009] In some embodiments, the shape sensing system further includes an SVC determiner algorithm configured to automatically determine a significant change in the strain of the fiber optic stylet at the moment when the tip of the medical device is pushed into the patient's SVC. The significant change in strain is an instantaneous increase in strain followed by an instantaneous decrease in strain.

[0010] In some embodiments, the SVC determiner algorithm is configured to confirm that the tip of the medical device is in the SVC by means of a periodic change in the strain of the fiber optic stylet sensed by the selected FBG sensors. The periodic change in strain is due to the periodic change in blood flow within the SVC, such as the patient's heartbeat.

[0011] In some embodiments, the shape sensing system further includes an optical fiber connector module configured to establish a first optical connection from the medical device to the optical fiber connection module and a second optical connection from the optical fiber connection module to the optical interrogator. The first optical connection is through a sterile drape, where the medical device is in a sterile area defined by the sterile drape and the optical fiber connector module is in a non-sterile area defined by the sterile drape.

[0012] In some embodiments, the fiber optic connector module includes one or more sensors selected from a gyroscope, an accelerometer, and a magnetometer. The one or more sensors are configured to provide sensor data to a console via one or more data lines to determine a reference plane for shape sensing using the fiber optic ferrule through an algorithm.

[0013] In some embodiments, the optical interrogator is an integrated optical interrogator integrated into the console.

[0014] In some embodiments, the display screen is an integrated display screen integrated into the console.

[0015] Also disclosed herein is a method for determining that the tip of a medical device is located within the SVC of a patient. In some embodiments, the method includes advancing the tip of the medical device through the vasculature of the patient towards the SVC. The medical device includes an integrated fiber optic ferrule having a plurality of FBG sensors along at least a distal portion of the fiber optic ferrule for shape sensing using a shape sensing system including the medical device. The method further includes enabling an input optical signal (e.g., broadband incident light) to be sent into the fiber optic ferrule while advancing the tip of the medical device through the vasculature of the patient. In one embodiment, the broadband incident light is provided by a light source, which may be a tunable swept laser, but other suitable light sources may be employed in addition to lasers, including semi-coherent light sources, LED light sources, etc. The method further includes enabling the optical signal reflected by the FBG sensors to be received from the fiber optic ferrule while advancing the tip of the medical device through the vasculature of the patient. The method further includes identifying a significant change in the strain of the fiber optic ferrule sensed by a selected FBG sensor in the distal portion of the fiber optic ferrule on a display screen of the shape sensing system at the moment the tip of the medical device is pushed into the SVC, thereby determining that the tip of the medical device is located within the SVC.

[0016] In some embodiments, the method further includes enabling the optical signal reflected by the FBG sensors received from the fiber optic ferrule to be converted into a plurality of different graphs through an algorithm for display on the display screen.

[0017] In some embodiments, each of the plurality of different graphs is selected from a graph of curvature versus arc length, torsion versus arc length, angle versus arc length, and position versus time of at least a distal portion of the fiber optic ferrule.

[0018] In some embodiments, the plurality of different graphs includes a graph of curvature versus time for each FBG sensor selected from the FBG sensors of the fiber optic ferrule.

[0019] In some embodiments, the method further includes enabling an optical signal reflected from an FBG sensor received from an optical fiber stylet to be converted by an algorithm into a displayable shape of a medical device for display on a display screen.

[0020] In some embodiments, a significant change in the strain of the optical fiber stylet is an instantaneous increase in the drawn curvature of the optical fiber stylet, followed by an instantaneous decrease in the drawn curvature.

[0021] In some embodiments, the magnitude of the instantaneous decrease in the drawn curvature of the optical fiber stylet is approximately twice the magnitude of the instantaneous increase in the drawn curvature.

[0022] In some embodiments, the selected FBG sensors are the last three FBG sensors in the distal portion of the optical fiber stylet.

[0023] In some embodiments, the method further includes, after determining that the tip of the medical device is in the SVC, stopping the advancement of the tip of the medical device through the patient's vasculature. The method also includes confirming that the tip of the medical device is in the SVC by means of a periodic change in the strain of the optical fiber stylet sensed by the selected FBG sensors. The periodic change in the strain is due to the periodic change in blood flow within the SVC (such as the patient's heartbeat).

[0024] In some embodiments, advancing the tip of the medical device through the patient's vasculature includes advancing the tip of the medical device through the right internal jugular vein, the right brachiocephalic vein, and into the SVC.

[0025] In some embodiments, the medical device is a CVC.

[0026] In some embodiments, advancing the tip of the medical device through the patient's vasculature includes advancing the tip of the medical device through the right basilic vein, the right axillary vein, the right subclavian vein, the right brachiocephalic vein, and into the SVC.

[0027] In some embodiments, the medical device is a peripherally inserted central catheter (PICC).

[0028] The present disclosure also provides a method for determining that the tip of a medical device is located within a patient's SVC. In some embodiments, the method includes advancing the tip of the medical device through the patient's vasculature toward the SVC. The medical device includes an integrated fiber optic stylet having a plurality of FBG sensors along at least a distal portion of the fiber optic stylet for shape sensing using a shape sensing system including the medical device. The method further includes enabling an input optical signal to be sent into the fiber optic stylet while advancing the tip of the medical device through the patient's vasculature. The method further includes enabling an optical signal reflected by the FBG sensors to be received from the fiber optic stylet while advancing the tip of the medical device through the patient's vasculature. The method further includes enabling the optical signal reflected by the FBG sensors received from the fiber optic stylet to be converted by an algorithm into a graph of curvature versus time for each of the FBG sensors in the FBG sensors. The method further includes, at the moment the tip of the medical device is pushed into the SVC, identifying on a display screen of the shape sensing system an instantaneous increase in strain of the fiber optic stylet sensed by each of the last three FBG sensors in the distal portion of the fiber optic stylet, followed by an instantaneous decrease in strain, thereby determining that the tip of the medical device is located within the SVC. The method further includes confirming that the tip of the medical device is in the SVC by means of a periodic change in strain of the fiber optic stylet sensed by the last three FBG sensors in the distal portion of the fiber optic stylet. The periodic change in strain is due to a periodic change in blood flow within the SVC (such as the patient's heartbeat).

[0029] These and other features of the concepts provided herein will become more apparent to those skilled in the art in view of the drawings and the following description of specific embodiments of such concepts, which are described in more detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a block diagram of a first shape sensing system according to some embodiments.

[0031] Figure 2 is a block diagram of a second shape sensing system according to some embodiments.

[0032] Figure 3 shows a second shape sensing system according to some embodiments.

[0033] Figure 4A shows a cross-section of a catheter tube of a medical device according to some embodiments.

[0034] Figure 4B shows a longitudinal section of a catheter tube of a medical device according to some embodiments.

[0035] Figure 5Shows a detailed portion of an optical fiber connector module according to some embodiments.

[0036] Figure 6 Shows a second shape sensing system having a first optical fiber connector module according to some embodiments.

[0037] Figure 7 Shows a second shape sensing system having a first optical fiber connector module within a fenestration of a surgical drape according to some embodiments.

[0038] Figure 8 Shows a second shape sensing system having a second optical fiber connector module according to some embodiments.

[0039] Figure 9 Shows a second shape sensing system having a second optical fiber connector module beneath a surgical drape according to some embodiments.

[0040] Figure 10 Provides a plurality of different graphs on a display screen of a shape sensing system according to some embodiments.

[0041] Figure 11 Provides as Figure 10 A detailed graph of the curvature versus arc length and twist versus arc length of at least the distal portion of an optical fiber stylet as one of the graphs.

[0042] Figure 12 Provides as Figure 10 A detailed graph of the angle versus arc length of at least the distal portion of an optical fiber stylet as one of the graphs.

[0043] Figure 13 Provides as Figure 10 A detailed graph of the position versus time of at least the distal portion of an optical fiber stylet as one of the graphs.

[0044] Figure 14 Provides a displayable shape of at least the distal portion of a medical device or an optical fiber stylet according to some embodiments.

[0045] Figure 15 Provides as Figure 10 A detailed graph of the curvature versus time of each FBG sensor selected from a plurality of FBG sensors of an optical fiber stylet as some of the graphs. Detailed Description

[0046] Before disclosing some specific embodiments in more detail, it should be understood that the specific embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that the specific embodiments disclosed herein may have features that can be easily separated from the specific embodiments and can be combined with or replaced by any of the features of a plurality of other embodiments disclosed herein at will.

[0047] Regarding the terms used herein, it should also be understood that these terms are for the purpose of describing some specific embodiments, and these 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 different steps in a group of features or a group of steps, and do not provide a sequence or numerical limitation. For example, the "first", "second", and "third" features or steps do not necessarily need to occur in sequence, and a specific embodiment including such features or steps does not necessarily need to be limited to these three features or steps. Labels such as "left", "right", "up", "down", "front", "back" are used for convenience and are not intended to imply, for example, any particular fixed position, orientation, or direction. Instead, such labels are used to reflect, for example, relative position, orientation, or direction. Unless otherwise clearly specified in the context, the singular forms "a", "an", and "the" include plural references.

[0048] For example, the "proximal", "proximal portion", or "proximal part" of a catheter disclosed herein includes the portion of the catheter that is intended to be close to the clinician when the catheter is used on a patient. Similarly, for example, the "proximal length" of a catheter includes a certain length of the catheter that is intended to be close to the clinician when the catheter is used on a patient. For example, the "proximal end" of a catheter includes one end of the catheter that is intended to be close to the clinician when the catheter is used on a patient. The proximal portion, proximal part, or proximal length of the catheter may include the proximal end of the catheter; however, the proximal portion, proximal part, or proximal length of the catheter does not need to include the proximal end of the catheter. That is, unless otherwise specified in the context, the proximal portion, proximal part, or proximal length of the catheter is not the terminal portion or terminal length of the catheter.

[0049] For example, the “distal,” “distal portion,” or “distal end portion” of the catheter disclosed herein includes the portion of the catheter that is intended to be near or within the patient when the catheter is used on a patient. Similarly, for example, the “distal length” of the catheter includes a length of the catheter that is intended to be near or within the patient when the catheter is used on a patient. For example, the “distal end” of the catheter includes one end of the catheter that is intended to be near or within the patient when the catheter is used on a patient. The distal portion, distal end portion, or distal length of the catheter may include the distal end of the catheter; however, the distal portion, distal end portion, or distal length of the catheter need not include the distal end of the catheter. That is, unless the context otherwise indicates, the distal portion, distal end portion, or distal length of the catheter is not the terminal portion or terminal length of the catheter.

[0050] The term “logic” can represent hardware, firmware, or software configured to perform one or more functions. As hardware, the term logic can refer to or include circuitry having data processing and / or storage capabilities. Embodiments of such circuitry can include, but are not limited to or restricted to, a hardware processor (e.g., a microprocessor, one or more processor cores, a digital signal processor, a programmable gate array, a microcontroller, an application specific integrated circuit “ASIC”, etc.), a semiconductor memory, or a combination thereof.

[0051] Additionally or alternatively, the term logic can refer to or include software such as one or more processes, one or more instances, application programming interface(s) (API(s)), 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. The software can be stored in any type of suitable non-transitory storage medium or transitory storage medium (e.g., an electrical, optical, acoustic, or other form of propagated signal such as a carrier wave, an infrared signal, or a digital signal). Embodiments of non-transitory storage media can include, but are not limited to or restricted to, programmable circuitry, non-permanent memory such as volatile memory (e.g., any type of random access memory “RAM”), or permanent memory such as non-volatile memory (e.g., read only memory “ROM”, power-backed RAM, flash memory, phase change memory, etc.), solid state drive, hard disk drive, optical disk drive, or portable storage device. As firmware, the logic can be stored in permanent memory.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

[0053] As described above, it is necessary for clinicians to easily and safely check whether the PICC and CVC are displaced for repositioning if necessary. The present disclosure discloses a shape sensing system and method for medical devices to solve the above problems.

[0054] For example, the shape sensing system may include a medical device, an optical interrogator, a console, and a display screen. In one embodiment, the medical device includes an integrated fiber optic stylet having FBG sensors along at least a distal portion of the fiber optic stylet. As noted above, alternatives to the fiber optic stylet include, but are not limited to or restricted to, fiber optic integrated guideways or fiber optic integrated wires. The optical interrogator may be configured to send an input optical signal (e.g., broadband incident light) into the fiber optic stylet and receive the optical signal reflected by the FBG sensors therefrom.

[0055] In some embodiments, the fiber optic stylet is configured to return information identifying its physical state (e.g., shape length, shape, and / or form) of: (i) a portion of the stylet (e.g., the tip, stylet segment, etc.) or a portion of the catheter containing at least a portion of the stylet (e.g., the tip, catheter segment, etc.), or (ii) all or most of the stylet or catheter within the patient (hereinafter described as the "physical state of the stylet" or "physical state of the catheter"). According to one embodiment of the present disclosure, the returned information can be obtained from reflected light signals of different spectral widths, where each reflected light signal corresponds to a portion of the broadband incident light propagating along the core of the optical fiber (hereinafter referred to as the "core optical fiber"), and this portion of the broadband incident light is reflected back to the core optical fiber by a specific sensor located on the core optical fiber. An illustrative example of the returned information may relate to the change in the signal characteristics of the reflected light signal returned from the sensor, where the wavelength shift is related to the (mechanical) strain on the core optical fiber. It should be understood that the optical fiber may include one or more cores, and an optical fiber including multiple cores is referred to as a "multi-core optical fiber".

[0056] In some embodiments where the stylet includes a multi-core optical fiber, each core optical fiber utilizes multiple sensors, and each sensor is configured to reflect a different spectral range (e.g., different light frequency ranges) of the incident light. Based on the type and degree of strain applied to each core optical fiber, the sensors associated with that core optical fiber can change (shift) the wavelength of the reflected light to convey the type and degree of strain on the core optical fiber at those positions of the core optical fiber occupied by the sensors. The sensors are spatially distributed at various positions of the core optical fiber between the proximal and distal ends of the stylet, so that the shape sensing of the stylet can be performed based on the analysis of the wavelength shift. In some embodiments, the shape sensing function is paired with the ability to pass an electrical signal through a conductive medium included as part of the stylet while passing through the same member (the stylet).

[0057] More specifically, in some embodiments, each core fiber in the multi-core optical fiber is configured with a sensor array that is spatially distributed over a defined length of the core fiber to generally sense external strain in those regions of the core fiber occupied by the sensors. Assuming that each sensor positioned along the same core fiber is configured to reflect light of a different specific spectral width, the sensor array can perform distributed measurements over the entire defined length of the multi-core optical fiber. These distributed measurements can include wavelength shifts related to the strain experienced by the sensors.

[0058] During operation, multiple optical reflections (also referred to as "reflected optical signals") return from each of the multiple core fibers of the multi-core optical fiber to the console. Each reflected optical signal can be uniquely associated with a different spectral width. The information associated with the reflected optical signals can be used to determine a three-dimensional representation of the physical state of the stylet within the patient. The core fibers can be spatially separated from the cladding of the optical fiber, and each core fiber is configured to individually return light of different spectral widths (e.g., specific optical wavelengths or ranges of optical wavelengths) reflected from a distributed array of sensors fabricated in each core fiber. A comparison of the detected wavelength shifts of the reflected light returned by the central core fiber (as a reference) and the surrounding peripheral core fibers can be used to determine the physical state of the stylet.

[0059] During the insertion and advancement of the catheter into the vasculature, the clinician can rely on the console to visualize the current physical state (e.g., shape) of the catheter guided by the stylet to avoid potential path deviations. Due to the different spatial positions of the peripheral core fibers within the multi-mode optical fiber cladding, changes in the angular direction of the stylet (such as bending relative to the central core fiber) will impose different types (e.g., compression or tension) and degrees of strain on each of the peripheral core fibers as well as the central core fiber. Different types and / or degrees of strain may cause different wavelength shifts to be imposed by the sensors in the core fibers, and the wavelength shifts can be measured to infer the physical state of the stylet (catheter).

[0060] The console is configured to convert the reflected optical signals into plottable data for display as a graph on a display screen. The graph includes a graph of the curvature of each FBG sensor in a selected FBG sensor in the distal portion of the fiber optic stylet versus time for identifying significant changes in the strain of the fiber optic stylet as the tip of the medical device is pushed into the patient's superior vena cava.

[0061] The console can further be configured to receive one or more electrical signals from the stylet, which, as mentioned above, can be configured to support both optical and electrical connections. The electrical signals can be processed by the logic of the console to determine the ECG waveform to be displayed when executed by a processor.

[0062] These and other features of the shape sensing systems and methods provided herein will become more apparent with reference to the accompanying drawings and following description, which provide in greater detail specific embodiments of the shape sensing systems and methods thereof.

[0063] Shape Sensing System

[0064] Figure 1 is a block diagram of a first shape sensing system 100 according to some embodiments. Figure 2 is a block diagram of a second shape sensing system 200 according to some embodiments. Figure 3 A second shape sensing system 200 is shown in accordance with some embodiments. Figure 10 A display screen 150 or 250 of a shape sensing system 100 or 200 according to some embodiments is provided. Figures 11 to 15 Provided in Figure 10 A detailed graph of multiple different graphs on the display screen 150 or 250.

[0065] As shown, shape sensing system 100 includes a medical device 110, a stand-alone optical interrogator 130, a console 140, and a display screen 150, such as a display screen of a stand-alone monitor. Shape sensing system 200 includes medical device 110, an integrated optical interrogator 230, a console 240, and an integrated display screen 250, wherein both the integrated optical interrogator 230 and the integrated display screen 250 are integrated into the console 240. Each of shape sensing systems 100 and 200 may further include a fiber optic connector module 120 configured to connect the medical device 110 to the rest of the shape sensing system 100 or 200, such as the optical interrogator 130 or a console 240 including the integrated optical interrogator 230.

[0066] As described in more detail below, the medical device 110 includes an integrated fiber optic stylet having a plurality of FBG sensors along at least a distal portion of the fiber optic stylet for shape sensing using the shape sensing system 100 or 200. (For embodiments of the integrated fiber optic stylet of the medical device 110, see Figure 4B The integrated optical fiber stylet 424 in the embodiment of the present invention. )

[0067] Certain features of the medical device 110, such as the PICC 310, are described in more detail below with respect to specific embodiments of the medical device 110. That is, some of the features described below with respect to one or more embodiments of the medical device 110 are shared between two or more embodiments of the medical device 110. Thus, when convenient for illustration, "medical device 110" generally refers herein to more than one embodiment of the medical device 110. Although certain features have been described with respect to specific embodiments of the medical device 110, such as the PICC 310.

[0068] Although shown only for the console 240, each of the consoles 140 and 240 includes one or more processors 242 and a memory 244 that includes a plurality of algorithms 246, such as one or more optical signal converter algorithms. The one or more optical signal converter algorithms are configured to convert optical signals reflected by FBG sensors of the fiber cannula of the medical device 110 into plottable data corresponding to a displayable shape of the medical device 110. The one or more optical signal converter algorithms are also configured to convert the reflected optical signals from the fiber cannula of the medical device 110 into plottable data for a plurality of other graphs of plottable data. The display screen 150 or 250 is configured to display the displayable shape of the medical device 110, or any graph of a plurality of graphs of other plottable data, on the 3D grid 1002.

[0069] More specifically, in some embodiments, the algorithm 246 may include shape sensing logic that is configured to compare the wavelength shifts measured by sensors deployed in each outer core fiber at the same measurement region (or the same spectral width) of the cannula, catheter, or guidewire with the wavelength shift at a central core fiber that is positioned along the central axis and operates as a bending neutral axis. Based on these analyses, the shape sensing logic may determine the shape presented by the core fiber in 3D space and may further determine the current physical state of the cannula, catheter, or guidewire in 3D space for rendering on the display screen 150 or 250.

[0070] Referring to Figure 10, the plurality of graphs can include a graph 1004 of curvature versus arc length, a graph 1006 of twist versus arc length, a graph 1008 of angle versus arc length, or a graph 1010 of position versus time for at least a distal portion of the fiber optic stylet. The plurality of graphs can further include at least a graph 1012a, 1012b, 1012c... 1012n of curvature versus time for each of the selected FBG sensors in the distal portion of the fiber optic stylet. Any one or more of the graphs 1012a, 1012b, 1012c... 1012n of curvature versus time for the selected FBG sensors in the distal portion of the fiber optic stylet can be used to manually identify a significant change in the strain of the fiber optic stylet by means of a significant change in the drawn curvature of the fiber optic stylet at the moment the tip of the medical device 110 is pushed into the patient's SVC. However, in Figure 10 and 15 , the three graphs 1012a, 1012b, and 1012c of curvature versus time shown are graphs of curvature versus time for the last three FBG sensors in the distal portion of the fiber optic stylet. The last three FBG sensors in the distal portion of the fiber optic stylet are particularly useful in identifying a significant change in the drawn curvature of the fiber optic stylet because when the tip of the medical device 110 is pushed into the patient's SVC, the above FBG sensors directly experience a physical change in curvature caused by tensile and compressive strains of the fiber optic stylet. An example of a significant change in the drawn curvature of the fiber optic stylet is as follows: as shown by the arrows in any of the graphs 1012a, 1012b, or 1012c of curvature versus time shown in Figure 15 , an instantaneous increase in the drawn curvature is followed by an instantaneous decrease in the drawn curvature with an amplitude approximately twice that of the instantaneous increase in the drawn curvature.

[0071] In addition to being able to use any one or more of the graphs of curvature versus time to manually identify a significant change in the strain of the fiber optic stylet at the moment the tip of the medical device 110 is pushed into the patient's SVC, any one or more of the graphs 1012a, 1012b, 1012c... 1012n of curvature versus time for the selected FBG sensors in the distal portion of the fiber optic stylet can be used to manually determine the position of the tip of the medical device 110 in the SVC by means of periodic changes in the strain of the fiber optic stylet. The periodic changes in the strain of the fiber optic stylet are evidenced by periodic changes in the drawn curvature of the fiber optic stylet sensed by the selected FBG sensors. (See Figure 10 and 15Three curvature vs. time graphs 1012a, 1012b, and 1012c, as shown in the position vs. time graph 1010, between approximately 860 s and 1175 s when the distal portion of the fiber cannula is held in place within the SVC. The periodic variation in the plotted curvature is due to the periodic variation in blood flow within the SVC sensed by the selected FBG sensor (such as the patient's heartbeat).

[0072] Each of the consoles 140 and 240 may also include an SVC determinant algorithm of one or more algorithms 246, configured to automatically determine a significant change in the strain of the fiber cannula at the moment the tip of the medical device 110 is pushed into the patient's SVC, by means of a significant change in the plotted curvature of the fiber cannula or the plottable data therefor. Again, a significant change in the plotted curvature is an instantaneous increase in the plotted curvature, followed by an instantaneous decrease in the plotted curvature having an amplitude approximately twice that of the instantaneous increase in the plotted curvature. The SVC determinant algorithm may also be configured to confirm that the tip of the medical device 110 is within the SVC by automatically determining the periodic variation in the plotted curvature of the fiber cannula sensed by the selected FBG sensor. (See Figure 10 and 15 Three curvature vs. time graphs 1012a, 1012b, and 1012c, as shown in the position vs. time graph 1010, between approximately 860 s and 1175 s when the distal portion of the fiber cannula is held in place within the SVC. The periodic variation in the plotted curvature is due to the periodic variation in blood flow within the SVC sensed by the selected FBG sensor with the patient's heartbeat.

[0073] The optical interrogator 130 or 230 is configured to send an input optical signal into the fiber cannula of the medical device 110 and receive a reflected optical signal from the fiber cannula. When the fiber optic connector module 120 is present in the shape sensing system 100 or 200, the optical interrogator 130 or 230 is configured to send an input optical signal into the fiber cannula of the medical device 110 by means of the fiber optic connector module 120 and receive a reflected optical signal from the fiber cannula by means of the fiber optic connector module 120.

[0074] In some embodiments, the optical interrogator 130 or 230 can be a photodetector such as a positive-intrinsic-negative "PIN" photodiode, an avalanche photodiode, etc. For such embodiments, the optical interrogator 130 or 230 can be configured to: (i) receive the returned optical signal, i.e., the reflected optical signal received from each fiber-based reflection grating (sensor) fabricated within each core optical fiber deployed within the stylet, catheter, wire, etc., and (ii) convert the reflected optical signal into reflected data, i.e., data in the form of an electrical signal representing the reflected optical signal including a wavelength shift caused by strain. The reflected optical signals associated with different spectral widths include the reflected optical signal provided by the sensor in the central core optical fiber (reference) of the multi-core optical fiber located in the stylet, catheter, guide wire, etc., and the reflected optical signal provided by the sensor in the outer core optical fiber located in the stylet, catheter, guide wire, etc.

[0075] The fiber optic connector module 120 includes a housing 324, a cable 326 extending from the housing 324, and an optical fiber 528 at least within the cable 326. (For the optical fiber 528, see Figure 5 .) The fiber optic connector module 120 is configured to establish a first optical connection between the fiber optic stylet of the medical device 110 and the optical fiber 528 of the fiber optic connector module 120. The fiber optic connector module 120 is also configured with a plug 330 at the end of the cable 326 to establish a second optical connection between the optical fiber 528 of the fiber optic connector module 120 and the optical interrogator 130 or 230. The optical fiber 528 of the fiber optic connector module 120 is configured to convey an input optical signal from the optical interrogator 130 or 230 to the fiber optic stylet of the medical device 110, and to transmit the reflected optical signal from the fiber optic stylet to the optical interrogator 130 or 230.

[0076] The fiber optic connector module 120 can further include one or more sensors 222 selected from at least a gyroscope, an accelerometer, and a magnetometer disposed within the housing 324. The one or more sensors 222 are configured to provide sensor data to the console 140 or 240 via one or more data lines at least within the cable 326 to determine a reference plane using a reference plane determinant algorithm of one or more algorithms 246, so as to perform shape sensing using the fiber optic stylet of the medical device 110.

[0077] The following specific embodiments of the fiber optic connector module 120, such as fiber optic connector modules 620 and 820, elaborate certain features of the fiber optic connector module 120 in more detail. That is, some of the features described below for one or more embodiments of the fiber optic connector module 120 are shared between two or more embodiments of the fiber optic connector module 120. Thus, when convenient for illustration purposes, "fiber optic connector module 120" is generally used herein to refer to more than one embodiment of the fiber optic connector module 120. Although certain features have been described with respect to specific embodiments of the fiber optic connector module 120, such as fiber optic connector modules 620 and 820.

[0078] Medical device

[0079] Figure 3 Also shown is a PICC 310 as a medical device 110 according to some embodiments. Figure 4A Shown is a cross-section of a catheter fitting 312 of a PICC 310 including an integrated fiber optic stylet 424 according to some embodiments. Figure 4B Shown is a longitudinal section of a catheter fitting 312 of a PICC 310 including an integrated fiber optic stylet 424 according to some embodiments.

[0080] As shown, the PICC 310 includes a catheter fitting 312, a bifurcated hub 314, two extension legs 316, and two Luer connectors 318 operatively connected in the foregoing order. The catheter fitting 312 includes two catheter lumens 413 and an optical fiber stylet 424 that, when extruded, is disposed in a longitudinal bead 425 of the catheter fitting 312, such as between the two catheter lumens 413. In some embodiments, the optical fiber stylet 424 includes a single-core optical fiber. In other embodiments, the optical fiber stylet 424 is a multi-core optical fiber stylet. Optionally, the PICC 310 may further include an electrocardiogram (“ECG”) stylet in the same or different longitudinal beads of the catheter fitting 312. The bifurcated hub 314 has two hub lumens fluidly connected to the two catheter lumens 413, respectively. Each of the two extension legs 316 has an extension leg lumen fluidly connected to one of the two hub lumens. The PICC 310 further includes a stylet extension tube 320 extending from the bifurcated hub 314. The stylet extension tube 320 may be a thinned portion of the catheter fitting 312 that includes the optical fiber stylet 424, or a thinned portion of the catheter fitting 312 disposed in another tube, both of which may terminate at a plug 322 for establishing an optical connection between the optical fiber 528 of the fiber optic connector module 120 and the optical fiber stylet 424 of the PICC 310.

[0081] The optical fiber stylet 424 includes a plurality of FBG sensors 426a, 426b, 426c... 426n along at least a distal portion of the optical fiber stylet 424 configured for shape sensing using the shape sensing system 100 or 200. The FBG sensors 426a, 426b, 426c... 426n include periodic variations in the refractive index of the optical fiber of the optical fiber stylet 424, thereby forming wavelength-specific reflectors configured to reflect an input optical signal transmitted by the optical interrogator 130 or 230 back into the optical fiber stylet 424. In embodiments where the optical fiber stylet 424 is a multi-core optical fiber stylet, each core fiber includes a plurality of FBG sensors 426a, 426b, 426c... 426n, Figure 4BParticularly shown are the last three FBG sensors 426a, 426b, and 426c in the distal portion of the fiber optic stylet 424, where the FBG sensors 426a, 426b, and 426c are particularly useful in some embodiments for identifying significant changes in the drawn curvature of the fiber optic stylet 424 as stated above. This is because, in this case, when the tip of the PICC 310 is pushed into the patient's SVC, the last three FBG sensors 426a, 426b, and 426c directly experience the physical change in the curvature of the fiber optic stylet 424. However, in other embodiments, in addition to, or in place of, the farthest three FBG sensors 426a, 426b, and 426c, the reflected light received from other FBG sensors can be used in the shape sensing function of the shape sensing system 100 or 200.

[0082] Although the PICC 310 is provided as a specific embodiment of the medical device 110 of the shape sensing system 100 or 200, it should be understood that any of a plurality of medical devices including catheters (such as CVCs) can include at least a fiber optic stylet and a stylet extension tube terminating in a plug to optionally establish an optical connection between the fiber optic stylet of the medical device and the optical interrogator 130 or 230 by means of the optical fiber 528 of the fiber optic connector module 120.

[0083] Fiber optic connector module

[0084] Figure 6 Shown is a second shape sensing system 200 having a first fiber optic connector module 620 according to some embodiments. Figure 7 Shown is a second shape sensing system 200 having a first fiber optic connector module 620 within the window 601 of the surgical drape 603 according to some embodiments. Figure 8 Shown is a second shape sensing system 200 having a second fiber optic connector module 820 according to some embodiments. Figure 9 Shown is a second shape sensing system 200 having a second fiber optic connector module 820 under the surgical drape 603 according to some embodiments. Figure 5 Shown is a detailed portion of a fiber optic connector module 120 such as the first fiber optic connector module 620 or the second fiber optic connector module 820 according to some of its embodiments.

[0085] As shown, the fiber optic connector module 620 or 820 includes a housing 324, a receptacle 532 disposed in the housing 324, a cable 326 extending from the housing 324, and an optical fiber 528 at least within the cable 326.

[0086] The receiving socket 532 includes an optical receiver configured to receive the insertion of an optical terminal of a plug of the medical device 110 (e.g., the plug 322 of the PICC 310) for establishing an optical connection between the fiber optic connector module 620 or 820 and the fiber optic cannula of the medical device 110 (e.g., the fiber optic cannula 424 of the PICC 310) when the plug is inserted into the receiving socket 532.

[0087] The cable 326 includes a plug 330 for establishing an optical connection between the fiber optic connector module 620 or 820 and the optical interrogator 230 of the console 240.

[0088] The optical fiber 528 extends from the receiving socket 532 through the cable 326 to the plug 330. The optical fiber 528 is configured to convey an input optical signal from the optical interrogator 230 to the fiber optic cannula of the medical device 110 (e.g., the fiber optic cannula 424 of the PICC 310), and to convey a reflected optical signal from the fiber optic cannula to the optical interrogator 230.

[0089] As described above, the fiber optic connector module 620 or 820 may further include one or more sensors 222 selected from a gyroscope, an accelerometer, and a magnetometer disposed within the housing 324. The one or more sensors 222 are configured to provide sensor data for determining a reference plane for shape sensing using the fiber optic cannula of the medical device 110 (e.g., the fiber optic cannula 424 of the PICC 310).

[0090] Although not shown, the fiber optic connector module 620 or 820 may further include a power line and a data line that extend from the one or more sensors 222 through the cable 326 to the plug 330 or another plug. When the one or more sensors 122 are present in the fiber optic connector module 620 or 820, the power line and the data line are configured to convey power to the one or more sensors 122, respectively, and to convey data from the one or more sensors 122 to the console 240.

[0091] The fiber optic connection module 620 is configured to be located within the window 601 of the surgical drape 603 adjacent to the percutaneous insertion site of the medical device 110 (e.g., a catheter such as the PICC 310). Since the fiber optic connection module 620 is configured to be located within the window 601 of the surgical drape 603, the fiber optic connection module 620 can be subjected to disinfection or sterilization. For example, the housing 324 of the fiber optic connection module 620 may be non-porous or chemically resistant to oxidizing agents. The fiber optic connection module 620 may be configured to use The product is manually disinfected, or the fiber optic connection module 620 can be configured to perform automatic high-level disinfection or sterilization using vaporized hydrogen peroxide by means of the Trophon from Nanosonics Inc. (Indianapolis, IN).

[0092] Compared to the fiber optic connection module 620, the fiber optic connection module 820 is configured to be located under the surgical drape 603 on the chest of the patient P. Thus, the fiber optic connection module 820 does not require the same level of disinfection or sterilization as the fiber optic connection module 620.

[0093] Although not shown, the housing 324 of the fiber optic connection module 820 includes a loop extending from the housing 324, a tether point integrated into the housing 324, a ball-lock-pin receiver integrated into the housing 324, or a similar device configured to attach a neck strap to the fiber optic connector module 820. The loop, tether point, ball-lock-pin receiver, etc. enable the fiber optic connector module 820 to be secured to the neck of the patient P when placed on the chest of the patient. Additionally or alternatively, the housing 324 includes a patient-facing surface (e.g., the back surface of the fiber optic connection module 820) configured to be adhered to the patient's chest. The patient-facing surface enables the fiber optic connector module 820 to be secured to the chest of the patient when placed on the chest of the patient, regardless of whether the fiber optic connection module 820 is also secured to the patient's neck.

[0094] Again, the receiving socket 532 includes an optical receiver configured to receive the insertion of the optical terminal of the plug of the medical device 110 (e.g., the plug 322 of the PICC 310) and form an optical connection when the plug is inserted into the receiving socket 532; however, with the fiber optic connection module 820, the optical connection is formed between the fiber optic connection module 820 and the medical device 110 together with the surgical drape 603. By opening a notch in the surgical drape 603, the receiving socket 532 and the plug of the medical device 110 at least achieve an optical connection from a sterile area (e.g., above the surgical drape 603) including the medical device 110 such as the PICC 310 to a non-sterile area (e.g., under the surgical drape 603) including the fiber optic connection module 820.

[0095] Method

[0096] Each of the various methods for determining whether the tip of the medical device 110 is located within the patient's SVC includes advancing the tip of the medical device 110 through the patient's vasculature toward the SVC. As described above, the medical device 110 (e.g., PICC 310) includes an integrated fiber optic stylet (e.g., fiber optic stylet 424) having a plurality of FBG sensors (e.g., FBG sensors 426a, 426b, 426c...426n) along at least a distal portion of the fiber optic stylet for shape sensing using a shape sensing system 100 or 200 that includes the medical device 110. When the medical device 110 is a PICC 310, advancing the tip of the PICC 310 through the patient's vasculature includes advancing the tip of the PICC 310 through the right internal jugular vein, the right brachiocephalic vein, and into the SVC. When the medical device is a CVC, advancing the tip of the CVC through the patient's vasculature includes advancing the tip of the CVC through the right basilic vein, the right axillary vein, the right subclavian vein, the right brachiocephalic vein, and into the SVC.

[0097] The method may include implementing certain functions of the shape sensing system 100 or 200 by: turning on the console 140 or 240, running one or more programs on the console 140 or 240, selecting FBG sensors in the distal portion of the fiber optic stylet for the curvature vs. time graphs 1012a, 1012b, 1012c... 1012n (e.g., selecting FBG sensors 426a, 426b, 426c... 426n), and performing operations required for various functions of the shape sensing system 100 or 200 such as optical or electrical connections. Implementing certain functions of the shape sensing system 100 or 200 may include enabling an input optical signal to be sent into the fiber optic stylet by the optical interrogator 130 or 230 of the shape sensing system 100 or 200 while advancing the tip of the medical device 110 through the patient's vasculature. Implementing certain functions of the shape sensing system 100 or 200 may include enabling an optical signal reflected by the FBG sensors to be received from the fiber optic stylet by the optical interrogator 130 or 230 while advancing the tip of the medical device 110 through the patient's vasculature. Implementing certain functions of the shape sensing system 100 or 200 may include enabling the optical signal reflected by the FBG sensors received from the fiber optic stylet to be algorithmically converted into a plurality of different graphs (e.g., curvature vs. arc length graph 1004, torque vs. arc length graph 1006, angle vs. arc length graph 1008, position vs. time graph 1010, one or more of the curvature vs. time graphs 1012a, 1012b, 1012c... 1012n, etc.) for display on the display screen 150 or 250. Implementing certain functions of the shape sensing system 100 or 200 may include enabling the optical signal reflected by the FBG sensors received from the fiber optic stylet to be algorithmically converted into a displayable shape of the medical device 110 on the 3D grid 1002 for display on the display screen 150 or 250.

[0098] The method may include manually identifying, at the moment when the tip of the medical device 110 is pushed into the SVC, a significant change in the curvature of the fiber cannula sensed by an FBG sensor in the distal portion of the fiber cannula by selecting on the display screen 150 or 250, thereby determining that the tip of the medical device 110 is within the SVC. Identifying a significant change on the display screen 150 or 250 may include, at the moment when the medical device 110 is pushed into the SVC, identifying an instantaneous increase in the drawn curvature of the fiber cannula sensed by each of the last three FBG sensors (e.g., FBG sensors 426a, 426b, and 426c) in the distal portion of the fiber cannula, followed by an instantaneous decrease in the drawn curvature. Additionally or alternatively, the method may include automatically determining, at the moment when the medical device 110 is pushed into the SVC, a significant change in the drawn curvature of the fiber cannula sensed by a selected FBG sensor in the distal portion of the fiber cannula or in its plottable data using an SVC determinant algorithm.

[0099] The method may include stopping the advancement of the tip of the medical device 110 through the patient's vasculature after determining that the tip of the medical device 110 is within the SVC. The method may include confirming that the tip of the medical device 110 is within the SVC by means of a periodic change in the drawn curvature of the fiber cannula sensed by a selected FBG sensor. The periodic change in the drawn curvature is due to the periodic change in the blood flow within the SVC with the patient's heartbeat.

[0100] In some alternative or additional embodiments, the logic of the shape sensing system 100 or 200 may be configured to generate a rendering of the current physical state of the cannula and thus a rendering of the current physical state of the catheter based on heuristics or run-time analysis. For example, the logic may be configured according to machine learning techniques to access a data store (repository) having pre-stored data (e.g., images, etc.) associated with different regions of the cannula where the core fiber experiences similar or identical wavelength shifts. Based on the pre-stored data, the current physical state of the cannula and / or catheter may be rendered. Alternatively, as another embodiment, the logic may be configured to determine, at run-time, a change in the physical state of each region of the cannula (and catheter) based on at least: (i) the resulting wavelength shift experienced by the core fiber, and (ii) the relationship of these wavelength shifts generated by sensors located along different outer core fibers at the same cross-sectional region of the cannula (or catheter) to the wavelength shift generated by the central core fiber sensor at the same cross-sectional region. It is contemplated that other processes and programs may be performed to utilize the wavelength shifts measured by the sensors along each core fiber to effect appropriate changes in the physical state of the cannula and / or catheter.

[0101] It should be noted that neither the shape sensing system 100 nor 200 requires X-rays to determine whether the tip of the medical device 110 is located within the patient's SVC. Thus, when using the shape sensing system 100 or 200, the patient need not be exposed to ionizing X-ray radiation. Additionally, neither the shape sensing system 100 nor 200 requires additional magnetic sensor fixation devices to determine whether the tip of the medical device 110 is located within the patient's SVC. Further, since the shape sensing system 100 or 200 does not require the use of a reliable ECG P wave (for placement of the tip of the medical device into the patient's SVC) as do some existing systems, the shape sensing system 100 or 200 can be used in patients with atrial fibrillation or other arrhythmias.

[0102] Although some specific embodiments have been disclosed herein and although the specific embodiments have been disclosed in detail, the specific embodiments are not intended to limit the scope of the concepts provided herein. Additional adaptations and / or modifications will be apparent to the ordinary skilled person in the art and, in a broader sense, these adaptations and / or modifications are also included. Thus, departures may be made from the specific embodiments disclosed herein without departing from the scope of the concepts provided herein.

Claims

1. A medical device, comprising: An elongated implementation body configured to be advanced through a patient's vasculature; And An optical fiber, comprising a cladding and one or more core optical fibers spatially disposed within the cladding, each of the one or more core optical fibers comprising a plurality of sensors distributed along a longitudinal length of the respective core optical fiber, and each sensor of the plurality of sensors being configured to: (i) Reflect optical signals of different spectral widths based on received incident light; and (ii) Alter a characteristic of the reflected optical signal for determining a physical state of the optical fiber.

2. The medical device according to claim 1, wherein the optical fiber is a multi-core optical fiber.

3. The medical device according to claim 1, wherein the elongated implementation body is one of a stylet, a catheter, and a guide wire.

4. The medical device according to claim 1, further comprising an isolation layer, wherein the optical fiber is encapsulated within the isolation layer, and a conductive medium is encapsulated within the isolation layer.

5. The medical device according to claim 1, wherein each sensor of the plurality of sensors constitutes a reflection grating located at different regions of the respective core optical fiber, and the reflection gratings are distributed along the longitudinal length of the respective core optical fiber.

6. The medical device according to claim 1, wherein the change in the characteristic of the reflected light includes a wavelength shift applied to the reflected optical signal to at least identify a type of strain.

7. The medical device according to claim 6, wherein the type of strain is compression or tension.

8. The medical device according to claim 1, further comprising a conductive medium configured to provide a path for an electrical signal detected at a distal portion of the conductive medium.

9. The medical device according to claim 1, wherein the electrical signal includes an electrocardiogram signal.

10. A medical device system for detecting the positioning of a medical device at a target site within a patient's vasculature, the system comprising: The medical device, comprising an optical fiber having one or more core optical fibers, each of the one or more core optical fibers comprising a plurality of sensors distributed along a longitudinal length of the respective core optical fiber, and each sensor of the plurality of sensors being configured to: (i) Reflect optical signals of different spectral widths based on received incident light, and (ii) Alter a characteristic of the reflected optical signal for determining a physical state of the optical fiber; And A console, comprising one or more processors and a non-transitory computer-readable medium having logic stored thereon, which when executed by the one or more processors, causes operations including: Providing a broadband incident optical signal to the optical fiber; Receiving reflected optical signals of different spectral widths of the broadband incident light from at least one or more of the plurality of sensors; Processing the reflected optical signals associated with the plurality of core optical fibers; And Determining whether the medical device is located at the target site of the patient based on the reflected optical signals.

11. The medical device system according to claim 10, wherein the optical fiber is a multi-core optical fiber.

12. The medical device system according to claim 10, wherein the medical device is one of a stylet, a catheter, and a guide wire.

13. The medical device system according to claim 10, wherein the target site is in one of the superior vena cava, the right atrium, and the inferior vena cava of the patient's vasculature.

14. The medical device system according to claim 10, wherein when executed by the one or more processors, the logic causes further operations including: generating a visual representation of the physical state of at least a portion of the medical device based on characteristics of the reflected optical signal.

15. The medical device system according to claim 14, wherein the visual representation is a three-dimensional visual representation of the physical state of at least a portion of the medical device based on characteristics of the reflected optical signal.

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