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. The 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 therefrom an optical signal reflected by the FBG sensor. The console may be configured to convert the reflected optical signal into plottable data to display a graph thereof on a display screen. The graph may include a graph of curvature versus time for each of the FBG sensors selected in the distal portion of the fiber optic stylet, for identifying significant changes 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] priority

[0002] This application claims the benefit of priority to U.S. Provisional Application No. 62 / 885,702, filed on August 12, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application relates to medical devices, and more particularly to shape sensing systems and methods for medical devices. Background Art

[0004] Sometimes, the tip of a peripherally inserted central catheter ("PICC") or central venous catheter ("CVC") may move and shift from the ideal position in the patient's superior vena cava ("SVC"). Clinicians who believe that such PICC or CVC has shifted usually check whether it is shifted through a chest X-ray and replace the PICC or CVC if necessary. However, X-rays expose patients to ionizing radiation. Therefore, clinicians need to easily and safely check whether PICC and CVC are displaced to reset them when necessary.

[0005] Disclosed herein are shape sensing systems and methods for medical devices that address the above-mentioned issues. Summary of the invention

[0006] Disclosed herein is 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 comprising an optical fiber, wherein the optical fiber is composed of a plurality of fiber Bragg grating ("FBG") sensors along at least a distal portion of the optical fiber. As will be discussed throughout this disclosure, one embodiment of the implementation body is an optical fiber integrated stylet. However, other embodiments of the implementation body include, but are not limited to, an integrated optical fiber guidewire or an integrated optical fiber catheter. The optical interrogator is configured to send an input optical signal into the optical fiber stylet and receive an optical signal reflected by the FBG sensor from the optical fiber stylet. The console includes a memory and one or more processors, which are configured to convert the optical signal reflected by the FBG sensor from the optical fiber stylet into plottable data by means of a plurality of 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 plottable data. The plurality of graphs includes at least a graph of curvature versus time for each of the selected FBG sensors in the distal portion of the fiber optic stylet for identifying significant changes in strain of the fiber optic stylet at the moment the tip of the medical device is advanced into the patient's SVC.

[0007] In some embodiments, the shape sensing system further includes an SVC determinator algorithm configured to automatically determine a significant change in strain of the fiber optic stylet at the moment the tip of the medical device is advanced into the patient's SVC. A significant change in strain is a transient increase in strain followed by a transient decrease in strain.

[0008] In some embodiments, the SVC Determinant Algorithm is configured to confirm that the tip of the medical device is in the SVC by means of cyclical changes in strain of the fiber optic stylet sensed by the selected FBG sensor. The cyclical changes in strain are due to cyclical changes in blood flow within the SVC (such as the patient's heartbeat).

[0009] In some embodiments, the shape sensing system further includes a fiber optic connector module configured to establish a first optical connection from the medical device to the fiber optic connection module and a second optical connection from the fiber optic connection module to the optical interrogator. The first optical connection is through a sterile drape, wherein the medical device is in a sterile area defined by the sterile drape and the fiber optic connector module is in a non-sterile area defined by the sterile drape.

[0010] 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 a fiber optic stylet through an algorithm.

[0011] In some embodiments, the optical interrogator is an integrated optical interrogator that is integrated into a console.

[0012] In some embodiments, the display screen is an integrated display screen integrated into the console.

[0013] 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 patient's vascular system 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 also includes enabling an input optical signal (e.g., broadband incident light) to be sent into the fiber optic stylet while advancing the tip of the medical device through the patient's vascular system. 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 used in addition to lasers, including semi-coherent light sources, LED light sources, and the like. The method also includes enabling an optical signal reflected by the FBG sensor to be received from the fiber optic stylet while advancing the tip of the medical device through the patient's vascular system. The method also includes identifying, on a display screen of the shape sensing system, a significant change in strain of the fiber optic stylet sensed by a selected FBG sensor in a distal portion of the fiber optic stylet when the tip of the medical device is advanced into the SVC, thereby determining that the tip of the medical device is within the SVC.

[0014] In some embodiments, the method further includes enabling an optical signal reflected from the FBG sensor received from the optical fiber stylet to be converted by an algorithm into a plurality of different graphs for display on a display screen.

[0015] In some embodiments, each of the plurality of different graphs is selected from a graph of curvature versus arc length, a graph of twist versus arc length, a graph of angle versus arc length, and a graph of position versus time of at least a distal portion of the fiber optic stylet.

[0016] 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 optical fiber stylet.

[0017] In some embodiments, the method further includes enabling an optical signal reflected from the FBG sensor received from the fiber optic stylet to be converted by an algorithm into a displayable shape of the medical device for display on a display screen.

[0018] In some embodiments, a significant change in strain of the optical fiber stylet is a transient increase in the drawn curvature of the optical fiber stylet, followed by a transient decrease in the drawn curvature.

[0019] 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.

[0020] In some embodiments, the selected FBG sensors are the last three FBG sensors in the distal portion of the optical fiber stylet.

[0021] In some embodiments, the method further includes stopping advancing the tip of the medical device through the patient's vasculature after determining that the tip of the medical device is located in the SVC. The method also includes confirming that the tip of the medical device is in the SVC by means of a cyclical change in strain of the fiber optic stylet sensed by the selected FBG sensor. The cyclical change in strain is due to cyclical changes in blood flow within the SVC (such as the patient's heartbeat).

[0022] 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.

[0023] In some embodiments, the medical device is a CVC.

[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 basilic vein, the right axillary vein, the right subclavian vein, the right brachiocephalic vein and into the SVC.

[0025] In some embodiments, the medical device is a peripherally inserted central catheter (PICC).

[0026] 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 patient's vascular system 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 also 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 vascular system. The method also includes enabling an optical signal reflected by the FBG sensor to be received from the fiber optic stylet while advancing the tip of the medical device through the patient's vascular system. The method also includes enabling an optical signal reflected by the FBG sensor received from the fiber optic stylet to be converted by an algorithm into a graph of curvature versus time for each FBG sensor in the FBG sensor. The method also includes identifying on a display screen of a shape sensing system a momentary increase in strain of the fiber optic stylet as sensed by each of the last three FBG sensors in the distal portion of the fiber optic stylet, followed by a momentary decrease in strain, at the moment the tip of the medical device is advanced into the SVC, thereby determining that the tip of the medical device is within the SVC. The method also includes confirming that the tip of the medical device is within the SVC by means of a periodic change in strain of the fiber optic stylet as sensed by the last three FBG sensors in the distal portion of the fiber optic stylet. The periodic change in strain is due to periodic changes in blood flow within the SVC (such as a patient's heartbeat).

[0027] These and other features of the concepts provided herein will become more readily apparent to those skilled in the art in view of the accompanying drawings and the following description, which describe in more detail specific embodiments of such concepts. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a block diagram of a first shape sensing system according to some embodiments.

[0029] Figure 2 is a block diagram of a second shape sensing system according to some embodiments.

[0030] Figure 3 A second shape sensing system is presented in accordance with some embodiments.

[0031] Figure 4A Shown is a cross-section of a catheter tube of a medical device according to some embodiments.

[0032] Figure 4B A longitudinal cross-section of a catheter tube of a medical device according to some embodiments is shown.

[0033] Figure 5Detailed portions of a fiber optic connector module are shown according to some embodiments.

[0034] Figure 6 A second shape sensing system having a first fiber optic connector module is presented according to some embodiments.

[0035] Figure 7 A second shape sensing system having a first fiber optic connector module within a fenestration of a surgical drape is shown according to some embodiments.

[0036] Figure 8 A second shape sensing system having a second fiber optic connector module is presented in accordance with some embodiments.

[0037] Fig. 9 A second shape sensing system with a second fiber optic connector module beneath a surgical drape is shown in accordance with some embodiments.

[0038] Fig.10 A plurality of different graphs on a display screen of a shape sensing system according to some embodiments are provided.

[0039] Fig.11 Provided as Fig.10 Detailed graphs of curvature versus arc length and twist versus arc length of at least a distal portion of a fiber optic stylet of one of the graphs.

[0040] Fig.12 Provided as Fig.10 One of the graphs is a detailed graph of angle versus arc length of at least a distal portion of a fiber optic stylet.

[0041] Fig.13 Provided as Fig.10 One of the graphs is a detailed graph of the position of at least a distal portion of the fiber optic stylet versus time.

[0042] Fig.14 A displayable shape of at least a distal portion of a medical device or fiber optic stylet according to some embodiments is provided.

[0043] Fig.15 Provided as Fig.10 Some graphs are detailed graphs of curvature versus time for each FBG sensor selected from a plurality of FBG sensors of an optical fiber stylet. DETAILED DESCRIPTION

[0044] 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 or replaced with any feature in multiple other embodiments disclosed herein at will.

[0045] About the terms used in this article, 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 set of features or a set of steps, and do not provide sequence or numerical restrictions. For example, "first", "second" and "third" features or steps do not necessarily need to appear in order, and the specific embodiments including such features or steps do 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, rather than being intended to imply any specific fixed position, orientation or direction, for example. On the contrary, such labels are used to reflect, for example, relative position, orientation or direction. Unless otherwise clearly indicated in the context, singular forms "one", "a kind of" and "the" include plural references.

[0046] For example, the "proximal side", "proximal portion" or "proximal end portion" of the catheter disclosed herein includes the portion of the catheter that is intended to be close to the clinician when the catheter is used on the patient. Similarly, for example, the "proximal length" of the catheter includes a certain length of the catheter that is intended to be close to the clinician when the catheter is used on the patient. For example, the "proximal end" of the catheter includes an end of the catheter that is intended to be close to the clinician when the catheter is used on the patient. The proximal portion, proximal portion or proximal length of the catheter can include the proximal end of the catheter; however, the proximal portion, proximal portion or proximal length of the catheter does not need to include the proximal end of the catheter. That is, unless the context otherwise indicates, the proximal portion, proximal portion or proximal length of the catheter is not the terminal portion or terminal length of the catheter.

[0047] For example, the "distal side", "distal portion" or "distal end portion" of the catheter disclosed herein includes the portion of the catheter intended to be close to the patient or in the patient when the catheter is used on the patient. Similarly, for example, the "distal length" of the catheter includes a certain length of the catheter intended to be close to the patient or in the patient when the catheter is used on the patient. For example, the "distal end" of the catheter includes an end of the catheter intended to be close to the patient or in the patient when the catheter is used on the patient. The distal portion, distal portion or distal length of the catheter can include the distal end of the catheter; however, the distal portion, distal portion or distal length of the catheter does not need to include the distal end of the catheter. That is, unless the context otherwise indicates, the distal portion, distal portion or distal length of the catheter is not the terminal portion or terminal length of the catheter.

[0048] The term "logic" may refer to hardware, firmware, or software configured to perform one or more functions. As hardware, the term logic may refer to or include circuitry having data processing and / or storage functions. Embodiments of such circuitry may include, but are not limited to, hardware processors (e.g., microprocessors, one or more processor cores, digital signal processors, programmable gate arrays, microcontrollers, application specific integrated circuits "ASICs", etc.), semiconductor memories, or a combination of elements.

[0049] Additionally or alternatively, the term logic may refer to or include software such as one or more processes, one or more instances, application programming interface (API) (one or more), subroutine (one or more), function (one or more), applet (one or more), servlet (one or more), routine (one or more), source code, object code, shared library / dynamic link library (dll) or even one or more instructions. The software may be stored in any type of suitable non-transient storage medium or transient storage medium (e.g., electrical, optical, acoustic or other forms of propagation signals, such as carrier waves, infrared signals or digital signals). Embodiments of non-transient storage media may include, but are not limited to, programmable circuits, non-permanent memories such as volatile memories (e.g., any type of random access memory "RAM"), or permanent memories such as non-volatile memories (e.g., read-only memory "ROM", RAM with power support, flash memory, phase change memory, etc.), solid-state drives, hard drives, optical disk drives or portable storage devices. As firmware, logic may be stored in permanent memory.

[0050] Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

[0051] As mentioned above, there is a need for clinicians to easily and safely check whether PICCs and CVCs are displaced so as to reposition them when necessary. This document discloses a shape sensing system and method for medical devices that solves the above problems.

[0052] 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 a FBG sensor 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, a fiber optic integrated guideway or a fiber optic integrated wire. The optical interrogator may be configured to send an input optical signal (e.g., broadband incident light) into the fiber optic stylet and receive an optical signal reflected by the FBG sensor.

[0053] In some embodiments, the optical fiber 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., tip, stylet segment, etc.) or a portion of a catheter containing at least a portion of the stylet (e.g., tip, catheter segment, etc.), or (ii) all or a majority of the stylet or catheter in a patient's body (hereinafter described as "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, wherein each reflected light signal corresponds to a portion of broadband incident light propagating along the core of the optical fiber (hereinafter referred to as the "core fiber"), which is reflected back to the core fiber by a specific sensor located on the core fiber. An illustrative example of the returned information can involve changes in signal characteristics of the reflected light signal returned from the sensor, wherein the wavelength shift is related to the (mechanical) strain on the core fiber. It should be understood that an optical fiber may include one or more cores, wherein an optical fiber including multiple cores is referred to as a "multi-core fiber."

[0054] 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 of incident light (e.g., a different optical frequency range). Based on the type and degree of strain applied to each core optical fiber, the sensor associated with the 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 stylet occupied by the sensor. The sensors are spatially distributed at various locations of the core optical fiber between the proximal and distal ends of the stylet, so that shape sensing of the stylet can be performed based on analysis of the wavelength shift. In some embodiments, the shape sensing functionality 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 component (the stylet).

[0055] More specifically, in some embodiments, each core fiber in a multi-core optical fiber is configured with a sensor array that is spatially distributed over a specified length of the core fiber to collectively sense external strains in those areas 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 make distributed measurements over the entire specified length of the multi-core optical fiber. These distributed measurements can include wavelength shifts that are related to the strain experienced by the sensors.

[0056] During operation, multiple light reflections (also referred to as "reflected light signals") are returned to the console from each of the multiple core fibers of the multi-core optical fiber. Each reflected light signal can be uniquely associated with a different spectral width. Information associated with the reflected light signals can be used to determine a three-dimensional representation of the physical state of a stylet within a patient's body. 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., a specific wavelength of light or a range of wavelengths of light) reflected from a distributed array of sensors fabricated in each core fiber. Comparison of the detected shift in the wavelength of reflected light returned by the central core fiber (as a reference) with the surrounding peripheral core fibers can be used to determine the physical state of the stylet.

[0057] During 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 fiber cladding, changes in the angular orientation of the stylet (such as bending relative to the central core fiber, etc.) will apply different types of strain (e.g., compression or tension) and degrees to each peripheral core fiber and the central core fiber. Different types and / or degrees of strain may cause the core fiber's sensor to apply different wavelength shifts, which can be measured to infer the physical state of the stylet (catheter).

[0058] The console is configured to convert the reflected optical signal into plottable data for displaying a graph thereof on a display screen. The graph includes a graph of curvature versus time for each of the selected FBG sensors in the distal portion of the fiber optic stylet for identifying significant changes in strain of the fiber optic stylet when the tip of the medical device is advanced into the superior vena cava of the patient.

[0059] The console may further be configured to receive one or more electrical signals from the stylet, which, as mentioned above, may be configured to support both optical and electrical connections. The electrical signals may be processed by logic of the console, which, when executed by the processor, determines the ECG waveform to be displayed.

[0060] 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.

[0061] Shape Sensing System

[0062] 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. Fig.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 Fig.10 A detailed graph of multiple different graphs on the display screen 150 or 250.

[0063] 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.

[0064] 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. )

[0065] Certain features of the medical device 110 are described in more detail below with respect to specific embodiments of the medical device 110, such as the PICC 310. That is, some 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 necessary for ease of description, "medical device 110" herein generally refers 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,

[0066] Although only shown with respect to console 240, each of consoles 140 and 240 includes one or more processors 242 and a memory 244, the memory 244 including 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 an optical signal reflected from an FBG sensor of an optical fiber stylet of medical device 110 into plottable data corresponding to a displayable shape of medical device 110. The one or more optical signal converter algorithms are also configured to convert an optical signal reflected from an optical fiber stylet of medical device 110 into plottable data of a plurality of other graphs of plottable data. Display screen 150 or 250 is configured to display a displayable shape of medical device 110, or any of a plurality of graphs of other plottable data, on 3-dimensional grid 1002.

[0067] More specifically, in some embodiments, the algorithm 246 may include shape sensing logic configured to compare the wavelength shift measured by the sensors deployed in each outer core fiber at the same measurement area (or the same spectral width) of the stylet, catheter, or guidewire with the wavelength shift at the center core fiber positioned along the central axis and operating as the bending neutral axis. Based on these analyses, the shape sensing logic can determine the shape that the core fiber presents in 3D space, and can further determine the current physical state of the stylet, catheter, or guidewire in 3D space for rendering on the display screen 150 or 250.

[0068] Reference Fig.10, the plurality of graphs may 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 of at least a distal portion of the fiber optic stylet. The plurality of graphs may further include graphs 1012a, 1012b, 1012c...1012n of at least curvature versus time of 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 of the selected FBG sensors in the distal portion of the fiber optic stylet may be used to manually identify significant changes in strain of the fiber optic stylet by means of significant changes in the plotted curvature of the fiber optic stylet at the moment the tip of the medical device 110 is advanced into the patient's SVC. However, at Fig.10 and 15 The three graphs 1012a, 1012b, and 1012c of curvature versus time shown in FIG. 1 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 significant changes in the drawn curvature of the fiber optic stylet because the FBG sensors directly experience the physical changes in curvature caused by the tensile and compressive strains of the fiber optic stylet as the tip of the medical device 110 is advanced into the patient's SVC. The significant changes in the drawn curvature of the fiber optic stylet are exemplified as follows: Fig.15 A transient increase in the plotted curvature, illustrated by an arrow in any of the curvature versus time graphs 1012a, 1012b, or 1012c shown in FIG. 1 , is followed by a transient decrease in the plotted curvature that is approximately twice the magnitude of the transient increase in the plotted curvature.

[0069] In addition to being able to use any one or more of the curvature versus time graphs to manually identify significant changes in the strain of the fiber optic stylet at the moment the tip of the medical device 110 is advanced into the patient's SVC, any one or more of the curvature versus time graphs 1012a, 1012b, 1012c...1012n of the selected FBG sensors in the distal portion of the fiber optic stylet can be used to manually determine that the tip of the medical device 110 is in the SVC by virtue 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 plotted curvature of the fiber optic stylet sensed by the selected FBG sensors. (See Fig.10 and 151012a, 1012b and 1012c in the three curvature versus time graphs 1012a, 1012b and 1012c, as shown in the position versus time graph 1010, when the distal portion of the fiber optic stylet is maintained in position in the SVC, between approximately 860s and 1175s. ) 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).

[0070] Each of consoles 140 and 240 may also include one or more algorithms 246 of an SVC Determinant algorithm configured to automatically determine, at the moment the tip of the medical device 110 is advanced into the patient's SVC, a significant change in strain of the fiber optic stylet by means of a significant change in the drawn curvature of the fiber optic stylet or plottable data therefor. Again, a significant change in the drawn curvature is a momentary increase in the drawn curvature followed by a momentary decrease in the drawn curvature having a magnitude approximately twice that of the momentary increase in the drawn curvature. The SVC Determinant algorithm may also be configured to confirm that the tip of the medical device 110 is in the SVC by means of automatically determining periodic changes in the drawn curvature of the fiber optic stylet sensed by a selected FBG sensor. (See Fig.10 and 15 1012a, 1012b and 1012c of the three curvature versus time graphs 1012a, 1012b and 1012c of the position versus time graph 1010, when the distal portion of the fiber optic stylet is maintained in position in the SVC, between approximately 860s and 1175s. ) The periodic variation of the plotted curvature is due to the periodic variation of blood flow within the SVC sensed by the selected FBG sensor with the patient's heartbeat.

[0071] The optical interrogator 130 or 230 is configured to send an input optical signal into the optical fiber stylet of the medical device 110 and receive a reflected optical signal from the optical fiber stylet. When the optical fiber 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 optical fiber stylet of the medical device 110 via the optical fiber connector module 120 and receive a reflected optical signal from the optical fiber stylet via the optical fiber connector module 120.

[0072] 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 a return optical signal, i.e., a reflected optical signal received from a fiber-based reflection grating (sensor) fabricated within each core optical fiber deployed within a stylet, catheter, guidewire, etc., and (ii) convert the reflected optical signal into reflection 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 reflected optical signals provided from a sensor in a central core optical fiber (reference) of a multi-core optical fiber located in a stylet, catheter, guidewire, etc., and reflected optical signals provided from a sensor in an outer core optical fiber of the stylet, catheter, guidewire, etc.

[0073] The fiber optic connector module 120 includes a housing 324, a cable 326 extending from the housing 324, and at least an optical fiber 528 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 optical fiber 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 the input optical signal from the optical interrogator 130 or 230 to the optical fiber stylet of the medical device 110, and to convey the reflected optical signal from the optical fiber stylet to the optical interrogator 130 or 230.

[0074] The fiber optic connector module 120 may 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 at least one or more data lines within the cable 326 to determine a reference plane using a reference plane determinant algorithm of the one or more algorithms 246 to perform shape sensing using the fiber optic stylet of the medical device 110.

[0075] Certain features of the fiber optic connector module 120 are described in more detail below with respect to specific embodiments of the fiber optic connector module 120, such as the fiber optic connector modules 620 and 820. That is, some features described below with respect to 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 necessary for ease of description, "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 the fiber optic connector modules 620 and 820.

[0076] Medical Devices

[0077] Figure 3 Also shown is a PICC 310 as the medical device 110 according to some embodiments. Figure 4A A cross-section of a catheter tube 312 of a PICC 310 including an integrated fiber optic stylet 424 is shown, according to some embodiments. Figure 4B A longitudinal cross-section of a catheter tube 312 of a PICC 310 including an integrated fiber optic stylet 424 is shown according to some embodiments.

[0078] As shown, PICC 310 includes a catheter tube 312, a branch sleeve (bifurcated hub) 314, two extension legs (extension leg) 316 and two Luer connectors (Luer connector) 318 that are operably connected in the aforementioned order. The catheter tube 312 includes two catheter lumens 413 and a fiber optic stylet 424, which is arranged in the longitudinal seam (longitudinal bead) 425 of the catheter tube 312 when extruded, such as between the two catheter lumens 413. In some embodiments, the fiber optic stylet 424 includes a single-core optical fiber. In other embodiments, the fiber optic stylet 424 is a multi-core fiber optic stylet. Optionally, in the same or different longitudinal seams of the catheter tube 312, the PICC 310 can further include an electrocardiogram ("ECG") stylet. The branch sleeve 314 has two sleeve lumens that are fluidly connected to the two catheter lumens 413 respectively. Each of the two extension branches 316 has an extension branch lumen that is fluidically connected to the lumen of the two cannula lumens. The PICC 310 further includes a stylet extension tube 320 extending from the branch cannula 314. The stylet extension tube 320 can be a thinned portion of the catheter tube 312 including the optical fiber stylet 424, or a thinned portion of the catheter tube 312 arranged in another tube, both of which can be terminated in a plug 322 for establishing an optical connection between the optical fiber 528 of the optical fiber connector module 120 and the optical fiber stylet 424 of the PICC 310.

[0079] 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, which are 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 a wavelength-specific reflector configured to reflect an input optical signal sent by the optical interrogator 130 or 230 into the optical fiber stylet 424. In an embodiment in which the optical fiber stylet 424 is a multi-core optical fiber stylet, each core optical fiber includes a plurality of FBG sensors 426a, 426b, 426c ... 426n, Figure 4BThe last three FBG sensors 426a, 426b, and 426c in the distal portion of the fiber optic stylet 424 are particularly illustrated, where the FBG sensors 426a, 426b, and 426c are particularly useful in identifying significant changes in the plotted curvature of the fiber optic stylet 424 as stated above in some embodiments. This is because, in this case, the last three FBG sensors 426a, 426b, and 426c directly experience the physical changes in the curvature of the fiber optic stylet 424 as the tip of the PICC 310 is advanced into the patient's SVC. However, in other embodiments, in addition to or in place of the farthest three FBG sensors 426a, 426b, and 426c, reflected light received from other FBG sensors can be used in the shape sensing function of the shape sensing system 100 or 200.

[0080] Although 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 a catheter (e.g., a CVC) may include at least a fiber optic stylet and a stylet extension tube terminating in a plug to establish an optical connection between the fiber optic stylet of the medical device and the optical interrogator 130 or 230, optionally with the aid of an optical fiber 528 of a fiber optic connector module 120.

[0081] Fiber Optic Connector Module

[0082] Figure 6 A second shape sensing system 200 is shown having a first fiber optic connector module 620 according to some embodiments. Figure 7 A second shape sensing system 200 is shown with a first fiber optic connector module 620 within a fenestration 601 of a surgical drape 603, according to some embodiments. Figure 8 A second shape sensing system 200 is shown having a second fiber optic connector module 820 according to some embodiments. Fig. 9 A second shape sensing system 200 with a second fiber optic connector module 820 is shown beneath a surgical drape 603 in accordance with some embodiments. Figure 5 Detailed portions of a fiber optic connector module 120, such as the first fiber optic connector module 620 or the second fiber optic connector module 820, are shown according to some embodiments thereof.

[0083] 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 at least an optical fiber 528 within the cable 326 .

[0084] The receiving seat 532 includes an optical receiver, which is 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), and is used to establish an optical connection between the fiber optic connector module 620 or 820 and the optical fiber stylet of the medical device 110 (e.g., the optical fiber stylet 424 of the PICC 310) when the plug is inserted into the receiving seat 532.

[0085] 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 .

[0086] The optical fiber 528 extends from the receptacle 532 through the cable 326 to the plug 330. The optical fiber 528 is configured to communicate the input optical signal from the optical interrogator 230 to the optical fiber stylet of the medical device 110 (e.g., the optical fiber stylet 424 of the PICC 310), and to communicate the reflected optical signal from the optical fiber stylet to the optical interrogator 230.

[0087] 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 a fiber optic stylet of a medical device 110 (e.g., a fiber optic stylet 424 of a PICC 310).

[0088] Although not shown, the fiber optic connector module 620 or 820 may further include power lines and data lines extending 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 lines and the data lines are configured to transmit power to the one or more sensors 122 and transmit data from the one or more sensors 122 to the console 240, respectively.

[0089] The fiber optic connection module 620 is configured to be located within the fenestration 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). Because the fiber optic connection module 620 is configured to be located within the fenestration 601 of the surgical drape 603, the fiber optic connection module 620 can be disinfected or sterilized. For example, the housing 324 of the fiber optic connection module 620 can be non-porous or chemically resistant to oxidizing agents. The fiber optic connection module 620 can be configured to be used with a Becton, Dickinson and Company (Franklin Lakes, NJ) The product may be manually sterilized, or the fiber optic connection module 620 may be configured for automatic high-level disinfection or sterilization using vaporized hydrogen peroxide with the aid of a Trophon from Nanosonics Inc. (Indianapolis, IN).

[0090] Compared to the fiber optic connection module 620 , the fiber optic connection module 820 is configured to be located below the surgical drape 603 on the chest of the patient P. As such, the fiber optic connection module 820 does not require the same level of disinfection or sterilization as the fiber optic connection module 620 .

[0091] Although not shown, the housing 324 of the fiber optic connection module 820 includes a ring 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 ring, 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 patient's chest. Additionally or alternatively, the housing 324 includes a patient-facing surface (e.g., the back 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 patient's chest when placed on the patient's chest, regardless of whether the fiber optic connection module 820 is also secured to the patient's neck.

[0092] Again, the receiving seat 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 an optical connection is formed when the plug is inserted into the receiving seat 532; however, using the fiber optic connector module 820, the optical connection is formed between the fiber optic connector module 820 and the medical device 110 together with the surgical drape 603. By opening a notch in the surgical drape 603, the receiving seat 532 and the plug of the medical device 110 at least realize an optical connection from the sterile area including the medical device 110 such as the PICC 310 (e.g., above the surgical drape 603) to the non-sterile area including the fiber optic connection module 820 (e.g., below the surgical drape 603).

[0093] method

[0094] Each of the plurality of methods for determining whether the tip of the medical device 110 is located within the SVC of the patient includes advancing the tip of the medical device 110 through the vasculature of the patient 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 including the medical device 110. When the medical device 110 is a PICC 310, advancing the tip of the PICC 310 through the vasculature of the patient 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 vasculature of the patient 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.

[0095] The method may include implementing certain functions of the shape sensing system 100 or 200 by opening the console 140 or 240, running one or more programs on the console 140 or 240, selecting a FBG sensor in the distal portion of the fiber optic stylet for the curvature versus time graphs 1012a, 1012b, 1012c ... 1012n (e.g., selecting FBG sensors 426a, 426b, 426c ... 426n), making optical or electrical connections, etc., as required for various functions of the shape sensing system 100 or 200. 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 vasculature of the patient. Implementing certain functions of shape sensing system 100 or 200 may include enabling optical signals reflected from the FBG sensor to be received by optical interrogator 130 or 230 from the fiber optic stylet while advancing the tip of medical device 110 through the vasculature of the patient. Implementing certain functions of shape sensing system 100 or 200 may include enabling optical signals reflected from the FBG sensor received from the fiber optic stylet to be algorithmically converted into a plurality of different graphs (e.g., graph 1004 of curvature versus arc length, graph 1006 of torque versus arc length, graph 1008 of angle versus arc length, graph 1010 of position versus time, one or more of graphs 1012a, 1012b, 1012c, ... 1012n of curvature versus time, etc.) for display on display screen 150 or 250. Implementing certain functions of shape sensing system 100 or 200 may include enabling algorithmically converting optical signals reflected from a FBG sensor received from a fiber optic stylet into a displayable shape of medical device 110 on a 3-dimensional grid 1002 for display on display screen 150 or 250 .

[0096] The method may include manually identifying on display screen 150 or 250 a significant change in the curvature of the fiber optic stylet sensed by a selected FBG sensor in the distal portion of the fiber optic stylet at the moment the tip of the medical device 110 is advanced into the SVC, thereby determining that the tip of the medical device 110 is located within the SVC. Identifying the significant change on display screen 150 or 250 may include identifying a momentary increase in the plotted curvature of the fiber optic stylet sensed by each of the last three FBG sensors (e.g., FBG sensors 426a, 426b, and 426c) in the distal portion of the fiber optic stylet, followed by a momentary decrease in the plotted curvature at the moment the medical device 110 is advanced into the SVC. Additionally or alternatively, the method may include automatically determining, using an SVC Determinant algorithm, a significant change in the plotted curvature of the fiber optic stylet sensed by a selected FBG sensor in the distal portion of the fiber optic stylet, or plottable data thereof, at the moment the medical device 110 is advanced into the SVC.

[0097] The method may include stopping advancing the tip of the medical device 110 through the patient's vasculature after determining that the tip of the medical device 110 is located in the SVC. The method may include confirming that the tip of the medical device 110 is in the SVC by means of a periodic change in the plotted curvature of the fiber optic stylet sensed by the selected FBG sensor. The periodic change in the plotted curvature is due to periodic changes in blood flow within the SVC with the patient's heartbeat.

[0098] In some alternative or additional embodiments, the logic of the shape sensing system 100 or 200 can be configured to generate a rendering of the current physical state of the stylet based on heuristics or run-time analysis, and thus generate a rendering of the current physical state of the catheter. For example, the logic can be configured according to machine learning techniques to access a data store (library) having pre-stored data (e.g., images, etc.) associated with different regions of the stylet in which the core fiber experiences similar or identical wavelength shifts. Based on the pre-stored data, the current physical state of the stylet and / or catheter can be rendered. Alternatively, as another embodiment, the logic can be configured to determine the change in the physical state of each region of the stylet (and catheter) at runtime based on at least the following: (i) the resulting wavelength shift experienced by the core fiber, and (ii) the relationship between these wavelength shifts generated by sensors positioned along different external core fibers at the same cross-sectional region of the stylet (or catheter) and the wavelength shift generated by the center core fiber sensor at the same cross-sectional region. It is contemplated that other processes and procedures may be performed to utilize the wavelength shifts measured by sensors along each core fiber to make appropriate changes in the physical state of the stylet and / or catheter.

[0099] Notably, neither shape sensing system 100 or 200 requires X-rays to be used to determine whether the tip of medical device 110 is within the patient's SVC. Thus, the patient does not have to be exposed to ionizing X-ray radiation when using shape sensing system 100 or 200. Additionally, neither shape sensing system 100 or 200 requires additional magnetic sensor fixtures to be used to determine whether the tip of medical device 110 is within the patient's SVC. Additionally, because shape sensing system 100 or 200 does not require the use of a reliable ECG P wave (for placing the tip of the medical device into the patient's SVC) as some existing systems do, shape sensing system 100 or 200 can be used with patients suffering from atrial fibrillation or other cardiac arrhythmias.

[0100] Although some specific embodiments have been disclosed herein, and although 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 those of ordinary skill in the art, and in broader aspects, these adaptations and / or modifications are also included. Therefore, departures from the specific embodiments disclosed herein may be made without departing from the scope of the concepts provided herein.

Claims

1. A shape sensing system for a medical device, comprising: A medical device comprising an integrated fiber optic stylet having a plurality of fiber Bragg grating sensors along at least a distal portion of the fiber optic stylet; an optical interrogator configured to send an input optical signal into the fiber optic stylet and receive an optical signal reflected by a fiber Bragg grating sensor from the fiber optic stylet; a console including a memory and one or more processors configured to convert optical signals reflected from the fiber Bragg grating sensor of the fiber stylet into plottable data with the aid of a plurality of optical signal converter algorithms; and a display screen configured to display any of a plurality of graphs of the plottable data, the plurality of graphs comprising at least a graph of curvature versus time of each of a selected one or more of the fiber Bragg grating sensors in the distal portion of the fiber optic stylet for identifying a significant change in strain of the fiber optic stylet at a time when the tip of the medical device is advanced into the superior vena cava of the patient, Also included is a superior vena cava determinant algorithm configured to automatically determine the significant change in the strain of the fiber optic stylet at the moment the tip of the medical device is advanced into the superior vena cava of the patient, the significant change in strain being a momentary increase in the strain followed by a momentary decrease in the strain.

2. The shape sensing system according to claim 1 further includes a fiber optic connector module configured to establish a first optical connection from the medical device to the fiber optic connector module and a second optical connection from the fiber optic connector module to the optical interrogator, the first optical connection passing through a sterile cover cloth, wherein the medical device is in a sterile area defined by the sterile cover cloth, and the fiber optic connector module is in a non-sterile area defined by the sterile cover cloth.

3. A shape sensing system according to claim 2, wherein the fiber optic connector module includes one or more sensors selected from a gyroscope, an accelerometer and a magnetometer, and the one or more sensors are configured to provide sensor data to the console through one or more data lines to determine a reference plane for shape sensing using the fiber optic core needle through an algorithm.

4. The shape sensing system of claim 1, wherein the optical interrogator is an integrated optical interrogator integrated into the console. 5 . The shape sensing system of claim 1 , wherein the display screen is an integrated display screen integrated into the console.

6. A shape sensing system for a medical device, comprising: A medical device comprising an integrated fiber optic stylet having a plurality of fiber Bragg grating sensors along at least a distal portion of the fiber optic stylet; an optical interrogator configured to send an input optical signal into the fiber optic stylet and receive an optical signal reflected by a fiber Bragg grating sensor from the fiber optic stylet; a console including a memory and one or more processors configured to convert optical signals reflected from the fiber Bragg grating sensor of the fiber stylet into plottable data with the aid of a plurality of optical signal converter algorithms; and a display screen configured to display any of a plurality of graphs of the plottable data, the plurality of graphs comprising at least a graph of curvature versus time for each of a selected one or more fiber Bragg grating sensors in the distal portion of the fiber optic stylet for identifying a significant change in strain of the fiber optic stylet at a time when the tip of the medical device is advanced into the superior vena cava of the patient, Also included is a superior vena cava determinant algorithm configured to confirm that the tip of the medical device is in the superior vena cava by means of the periodic variation of the strain of the fiber optic stylet sensed by the selected fiber Bragg grating sensor, wherein the periodic variation of the strain is due to the periodic variation of the blood flow in the superior vena cava with the patient's heartbeat.

7. The shape sensing system according to claim 6 further includes a fiber optic connector module configured to establish a first optical connection from the medical device to the fiber optic connector module and a second optical connection from the fiber optic connector module to the optical interrogator, the first optical connection passing through a sterile cover cloth, wherein the medical device is in a sterile area defined by the sterile cover cloth, and the fiber optic connector module is in a non-sterile area defined by the sterile cover cloth.

8. A shape sensing system according to claim 7, wherein the fiber optic connector module includes one or more sensors selected from a gyroscope, an accelerometer and a magnetometer, and the one or more sensors are configured to provide sensor data to the console through one or more data lines to determine a reference plane for shape sensing using the fiber optic core needle through an algorithm.

9. The shape sensing system of claim 6, wherein the optical interrogator is an integrated optical interrogator integrated into the console.

10. The shape sensing system of claim 6, wherein the display screen is an integrated display screen integrated into the console.

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