Patent Publication Number: US-2022211442-A1

Title: Needle Guidance Using Fiber Optic Shape Sensing

Description:
PRIORITY 
     This application claims the benefit of priority to U.S. Provisional Application No. 63/134,523, filed Jan. 6, 2021, which is incorporated by reference in its entirety into this application. 
    
    
     BACKGROUND 
     In the past, certain intravascular guidance of medical instruments, such as guidewires and catheters for example, have used fluoroscopic methods for tracking tips of the medical instruments and determining whether distal tips are appropriately localized in their target anatomical structures. However, such fluoroscopic methods expose patients and their attending clinicians to harmful X-ray radiation. Moreover, in some cases, the patients are exposed to potentially harmful contrast media needed for the fluoroscopic methods. 
     More recently, electromagnetic tracking systems have been used involving stylets. Generally, electromagnetic tracking systems feature three components: a field generator, a sensor unit and control unit. The field generator uses several coils to generate a position-varying magnetic field, which is used to establish a coordinate space. Attached to the stylet, such as near a distal end (tip) of the stylet for example, the sensor unit includes small coils in which current is induced via the magnetic field. Based on the electrical properties of each coil, the position and orientation of the medical instrument may be determined within the coordinate space. The control unit controls the field generator and captures data from the sensor unit. 
     Although electromagnetic tracking systems avoid line-of-sight reliance in tracking the tip of a stylet while obviating radiation exposure and potentially harmful contrast media associated with fluoroscopic methods, electromagnetic tracking systems are prone to interference. More specifically, since electromagnetic tracking systems depend on the measurement of magnetic fields produced by the field generator, these systems are subject to electromagnetic field interference, which may be caused by the presence of many different types of consumer electronics such as cellular telephones. Additionally, electromagnetic tracking systems are subject to signal drop out, depend on an external sensor, and are defined to a limited depth range. 
     Disclosed herein is a system including a medical instrument monitoring system including a medical instrument having disposed therein an optical fiber and methods performed thereby where the system is configured to provide tracking information of a distal tip of the medical instrument using optical fiber technology to assist a clinician in inserting the medical instrument within a patient vasculature. In some embodiments, an optical fiber may be coupled to the medical instrument and to a console, where the optical fiber includes a known bend or kink, which may serve as a point of reference when determining a positioning or orientation of the medical instrument. In some embodiments, the optical fiber may be coupled to an ultrasound probe such that the known bend or kink is disposed at the coupling point. In other embodiments, the optical fiber may be coupled to the patient such that the known bend or kink is disposed at the coupling point. Further, some embodiments combine the fiber optic shape sensing functionality with one or more of intravascular electrocardiogram (ECG) monitoring, impedance/conductance sensing and blood flow directional detection. 
     SUMMARY 
     Briefly summarized, embodiments disclosed herein are directed to systems, apparatus and methods for providing tracking information of a distal tip of the medical instrument using optical fiber technology. In some embodiments, the medical instrument includes an optical fiber having one or more optical fiber cores, where each are configured with an array of sensors (reflective gratings), which are spatially distributed over a prescribed length of the core fiber to generally sense external strain and temperature on those regions of the core fiber occupied by the sensor. Each optical fiber core is configured to receive light (e.g., broadband) from a console during advancement through the vasculature of a patient, where the broadband light propagates along at least a partial distance of the optical fiber core toward the distal end. Given that each sensor positioned along the optical fiber core is configured to reflect light of a different, specific spectral width, the array of sensors enables distributed measurements throughout the prescribed length of the medical instrument. These distributed measurements may include wavelength shifts having a correlation with strain and/or temperature experienced by the sensor. 
     The reflected light from the sensors (reflective gratings) within an optical fiber core is returned from the medical instrument for processing by the console. The physical state of the medical instrument may be ascertained based on analytics of the wavelength shifts of the reflected light. For example, the strain caused through bending of the medical instrument and hence angular modification of the optical fiber core, causes different degrees of deformation. The different degrees of deformation alter the shape of the sensors (reflective grating) positioned on the optical fiber core, which may cause variations (shifts) in the wavelength of the reflected light from the sensors positioned on the optical fiber core. The optical fiber core may comprise a single optical fiber, or a plurality of optical fibers (in which case, the optical fiber core is referred to as a “multi-core optical fiber”). 
     As used herein, the term “core fiber,” generally refers to a single optical fiber core disposed within a medical instrument. Thus, discussion of a core fiber refers to single optical fiber core and discussion of a multi-core optical fiber refers to a plurality of core fibers. Various embodiments discussed below to detection of the health (and particularly the damage) that occurs in each of an optical fiber core of medical instrument including (i) a single core fiber, and (ii) a plurality of core fibers. It is noted that in addition to strain altering the shape of a sensor, ambient temperature variations may also alter the shape of a sensor, thereby causing variations (shifts) in the wavelength of the reflected light from the sensors positioned on the optical fiber core. 
     Specific embodiments of the disclosure include utilization of a medical instrument, such as a stylet, featuring a multi-core optical fiber and a conductive medium that collectively operate for tracking placement with a body of a patient of the stylet or another medical instrument (such as a catheter) in which the stylet is disposed. In lieu of a stylet, a guidewire may be utilized. For convenience, embodiments are generally discussed where the optical fiber core is disposed within a stylet; however, the disclosure is not intended to be so limited as the functionality involving detection of the health of an optical fiber core disclosed herein may be implemented regardless of the medical instrument in which the optical fiber core is disposed. In some embodiments, the optical fiber core may be integrated directly into a wall of the catheter. 
     In some embodiments, the optical fiber core of a stylet is configured to return information for use in identifying its physical state (e.g., shape length, shape, and/or form) of (i) a portion of the stylet (e.g., tip, segment of stylet, etc.) or a portion of a catheter inclusive of at least a portion of the stylet (e.g., tip, segment of catheter, etc.) or (ii) the entirety or a substantial portion of the stylet or catheter within the body of a patient (hereinafter, described as the “physical state of the stylet” or the “physical state of the catheter”). According to one embodiment of the disclosure, the returned information may be obtained from reflected light signals of different spectral widths, where each reflected light signal corresponds to a portion of broadband incident light propagating along a core of the multi-core optical fiber (core fiber) that is reflected back over the core fiber by a particular sensor located on the core fiber. One illustrative example of the returned information may pertain to a change in signal characteristics of the reflected light signal returned from the sensor, where wavelength shift is correlated to (mechanical) strain on the core fiber or a detected change in ambient temperature. 
     In some embodiments, the core fiber utilizes a plurality of sensors and each sensor is configured to reflect a different spectral range of the incident light (e.g., different light frequency range). Based on the type and degree of strain asserted on each core fiber, the sensors associated with that core fiber may alter (shift) the wavelength of the reflected light to convey the type and degree of stain on that core fiber at those locations of the stylet occupied by the sensors. The sensors are spatially distributed at various locations of the core fiber between a proximal end and a distal end of the stylet so that shape sensing of the stylet may be conducted based on analytics of the wavelength shifts. Herein, the shape sensing functionality is paired with the ability to simultaneously pass an electrical signal through the same member (stylet) through conductive medium included as part of the stylet. 
     Similarly, the sensors may alter (shift) the wavelength of the reflected light to convey sensed variations in ambient temperature. The alterations in response to detected variations in ambient temperature thereby provide for a temperature sensing functionality. 
     More specifically, in some embodiments each core fiber of the multi-core optical fiber is configured with an array of sensors, which are spatially distributed over a prescribed length of the core fiber to generally sense external strain on or variations in ambient temperature proximate those regions of the core fiber occupied by the sensor. Given that each sensor positioned along the same core fiber is configured to reflect light of a different, specific spectral width, the array of sensors enables distributed measurements throughout the prescribed length of the multi-core optical fiber. These distributed measurements may include wavelength shifts having a correlation with strain experienced and/or temperature variations detected by the sensor. 
     In more detail, each sensor may operate as a reflective grating such as a fiber Bragg grating (FBG), namely an intrinsic sensor corresponding to a permanent, periodic refractive index change inscribed into the core fiber. Stated differently, the sensor operates as a light reflective mirror for a specific spectral width (e.g., a specific wavelength or specific range of wavelengths). As a result, as broadband incident light is supplied by an optical light source and propagates through a particular core fiber, upon reaching a first sensor of the distributed array of sensors for that core fiber, light of a prescribed spectral width associated with the first sensor is reflected back to an optical receiver within a console, including a display and the optical light source. The remaining spectrum of the incident light continues propagation through the core fiber toward a distal end of the stylet. The remaining spectrum of the incident light may encounter other sensors from the distributed array of sensors, where each of these sensors is fabricated to reflect light with different specific spectral widths to provide distributed measurements, as described above. 
     During operation, multiple light reflections (also referred to as “reflected light signals”) are returned to the console from each of the plurality of core fibers of the multi-core optical fiber. Each reflected light signal may be uniquely associated with a different spectral width. Information associated with the reflected light signals may be used to determine a three-dimensional representation of the physical state of the stylet within the body of a patient through detection of strain in response to emitted incident light. Herein, the core fibers are spatially separated with the cladding of the multi-mode optical fiber and each core fiber is configured to separately return light of different spectral widths (e.g., specific light wavelength or a range of light wavelengths) reflected from the distributed array of sensors fabricated in each of the core fibers. 
     During vasculature insertion and advancement of the catheter, the clinician may rely on the console to visualize a current physical state (e.g., shape) of a catheter guided by the stylet to avoid potential path deviations. As the periphery core fibers reside at spatially different locations within the cladding of the multi-mode optical fiber, changes in angular orientation (such as bending with respect to the center core fiber, etc.) of the stylet imposes different types (e.g., compression or tension) and degrees of strain on each of the periphery core fibers as well as the center core fiber. The different types and/or degree of strain may cause the sensors of the core fibers to apply different wavelength shifts, which can be measured to extrapolate the physical state of the stylet (catheter). 
     Additionally, in some embodiments, a predetermined bend may be created within the optical fiber transmitting incident light and reflected light signals between a console and the optically-enabled medical instrument such that the predetermined bend results in a constant and consistent wavelength shift such that logic of the console may determine a positioning and orientation of the medical instrument, and particularly a distal tip thereof, relative to the known bend. Determining the positioning and orientation of the medical instrument enables the logic to generate an image of the medical instrument in space relative to the known bend, the image may then be utilized as an overlay on an ultrasound image providing a clinician a visual representation of the positioning and orientation of the medical instrument within the ultrasound imaging area. In some embodiments, the predetermined bend may be due to attaching the optical fiber to an ultrasound probe such that the positioning and orientation of the medical instrument are determined relative to the positioning of the ultrasound probe. 
     Embodiments of the disclosure may include a combination of one or more of the methodologies to confirm that an optical fiber within a medical instrument (e.g., an introducer wire, a guidewire, a stylet within a needle, a needle with fiber optic inlayed into the cannula, a stylet configured for use with a catheter, an optical fiber between a needle and a catheter, and/or an optical fiber integrated into a catheter) is located at a specified location with the vasculature based on oximetry readings determined from light reflected from one or more sensors disposed at the distal tip of the optical fiber. 
     Herein, some embodiments disclose a medical instrument system for inserting a medical instrument within a patient body, the system comprising the medical instrument comprising a first optical fiber having one or more of core fibers, an interconnect, wherein a distal end of the interconnect is optically coupled to the medical instrument, the interconnect including a second optical fiber having one or more of core fibers, wherein a predetermined bend is formed in the interconnect at a point along the length of the interconnect, and a console optically coupled to a proximal end of the interconnect. The console includes one or more processors and a non-transitory computer-readable medium having stored thereon logic, when executed by the one or more processors, causes operations including providing an incident light signal to the first optical fiber and the second optical fiber, receiving reflected light signals of different spectral widths of the incident light from the first optical fiber and the second optical fiber, processing the reflected light signals to determine a positioning and an orientation of the medical instrument relative to the predetermined bend, generating a display of the medical instrument based on the reflected light signals and the determination of the positioning and the orientation of the medical instrument relative to the predetermined bend, and causing rendering of the display of the medical instrument on a display screen. 
     In some embodiments, the medical instrument includes a stylet. In additional embodiments, the medical instrument further includes a needle, and wherein the stylet is disposed within a lumen of the needle. In some embodiments, the system further comprises an ultrasound probe coupled to the console, wherein the interconnect is coupled to the ultrasound probe causing the predetermined bend in the interconnect such that the positioning and the orientation of the medical instrument is determined relative to the ultrasound probe. In some embodiments, the logic, when executed by the one or more processors, causes further operations including receiving ultrasound imaging data from the ultrasound probe, and causing rendering of an ultrasound image from the ultrasound imaging data, wherein the display of the medical instrument is rendered as an overlay on the ultrasound image. 
     In yet further embodiments, the interconnect is coupled to the patient causing the predetermined bend in the interconnect such that the positioning and the orientation of the medical instrument is determined relative to the patient. In some embodiments, each of the one or more core fibers of the first optical fiber and the second optical fiber includes a plurality of sensors distributed along a longitudinal length of a corresponding core fiber and each sensor of the plurality of sensors is configured to (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of a corresponding optical fiber. 
     In yet additional embodiments, the optical fiber is a single-core optical fiber, and wherein the incident light is provided in pulses. In some embodiments, the optical fiber is a multi-core optical fiber including a plurality of core fibers. In some embodiments, the medical instrument is one of an introducer wire, a guidewire, a needle with the first optical fiber inlayed into a cannula of the needle or a catheter with the first optical fiber inlayed into one or more walls of the catheter. 
     Other embodiments disclose a method for inserting a medical instrument within a patient body, the method comprising providing an incident light signal to a first optical fiber included within the medical instrument and a second optical fiber included within an interconnect, wherein each of the first optical fiber and the second optical fiber include one or more of core fibers, and wherein a distal end of the interconnect is optically coupled to the medical instrument, receiving reflected light signals of different spectral widths of the incident light from the first optical fiber and the second optical fiber, processing the reflected light signals to determine a positioning and an orientation of the medical instrument relative to the predetermined bend, generating a display of the medical instrument based on the reflected light signals and the determination of the positioning and the orientation of the medical instrument relative to the predetermined bend, and causing rendering of the display of the medical instrument on a display screen. 
     In some embodiments, the medical instrument includes a stylet. In additional embodiments, the medical instrument further includes a needle, and wherein the stylet is disposed within a lumen of the needle. In some embodiments, the system further comprises an ultrasound probe coupled to the console, wherein the interconnect is coupled to the ultrasound probe causing the predetermined bend in the interconnect such that the positioning and the orientation of the medical instrument is determined relative to the ultrasound probe. In some embodiments, the logic, when executed by the one or more processors, causes further operations including receiving ultrasound imaging data from the ultrasound probe, and causing rendering of an ultrasound image from the ultrasound imaging data, wherein the display of the medical instrument is rendered as an overlay on the ultrasound image. 
     In yet further embodiments, the interconnect is coupled to the patient causing the predetermined bend in the interconnect such that the positioning and the orientation of the medical instrument is determined relative to the patient. In some embodiments, each of the one or more core fibers of the first optical fiber and the second optical fiber includes a plurality of sensors distributed along a longitudinal length of a corresponding core fiber and each sensor of the plurality of sensors is configured to (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of a corresponding optical fiber. 
     In yet additional embodiments, the optical fiber is a single-core optical fiber, and wherein the incident light is provided in pulses. In some embodiments, the optical fiber is a multi-core optical fiber including a plurality of core fibers. In some embodiments, the medical instrument is one of an introducer wire, a guidewire, a needle with the first optical fiber inlayed into a cannula of the needle or a catheter with the first optical fiber inlayed into one or more walls of the catheter. 
     Still other embodiments disclose a non-transitory, computer-readable medium having logic stored thereon that, when executed by one or more processors, causes operations comprising providing an incident light signal to a first optical fiber included within a medical instrument and a second optical fiber included within an interconnect, wherein each of the first optical fiber and the second optical fiber include one or more of core fibers, and wherein a distal end of the interconnect is optically coupled to the medical instrument, receiving reflected light signals of different spectral widths of the incident light from the first optical fiber and the second optical fiber, processing the reflected light signals to determine a positioning and an orientation of the medical instrument relative to the predetermined bend, generating a display of the medical instrument based on the reflected light signals and the determination of the positioning and the orientation of the medical instrument relative to the predetermined bend, and causing rendering of the display of the medical instrument on a display screen. 
     In some embodiments, the medical instrument includes a stylet. In additional embodiments, the medical instrument further includes a needle, and wherein the stylet is disposed within a lumen of the needle. In some embodiments, the system further comprises an ultrasound probe coupled to the console, wherein the interconnect is coupled to the ultrasound probe causing the predetermined bend in the interconnect such that the positioning and the orientation of the medical instrument is determined relative to the ultrasound probe. In some embodiments, the logic, when executed by the one or more processors, causes further operations including receiving ultrasound imaging data from the ultrasound probe, and causing rendering of an ultrasound image from the ultrasound imaging data, wherein the display of the medical instrument is rendered as an overlay on the ultrasound image. 
     In yet further embodiments, the interconnect is coupled to the patient causing the predetermined bend in the interconnect such that the positioning and the orientation of the medical instrument is determined relative to the patient. In some embodiments, each of the one or more core fibers of the first optical fiber and the second optical fiber includes a plurality of sensors distributed along a longitudinal length of a corresponding core fiber and each sensor of the plurality of sensors is configured to (i) reflect a light signal of a different spectral width based on received incident light, and (ii) change a characteristic of the reflected light signal for use in determining a physical state of a corresponding optical fiber. 
     In yet additional embodiments, the optical fiber is a single-core optical fiber, and wherein the incident light is provided in pulses. In some embodiments, the optical fiber is a multi-core optical fiber including a plurality of core fibers. In some embodiments, the medical instrument is one of an introducer wire, a guidewire, a needle with the first optical fiber inlayed into a cannula of the needle or a catheter with the first optical fiber inlayed into one or more walls of the catheter. 
     Some embodiments of the disclosure include a medical instrument system for inserting a medical instrument within a patient body, the system comprising the medical instrument comprising a first optical fiber having one or more of core fibers, a console optically coupled to the medical instrument, the console including one or more processors and a non-transitory computer-readable medium having stored thereon logic, when executed by the one or more processors, causes operations including providing an incident light signal to the first optical fiber, receiving reflected light signals of different spectral widths of the incident light from the first optical fiber, processing the reflected light signals to determine a positioning and an orientation of the medical instrument, generating a display of the medical instrument based on the reflected light signals and the determination of the positioning and the orientation of the medical instrument, and causing rendering of the display of the medical instrument on a display screen. 
     In some embodiments, the system further comprises an interconnect, wherein a distal end of the interconnect is optically coupled to the medical instrument and a proximal end of the interconnect is optically coupled to the console, wherein the interconnect includes a second optical fiber having one or more of core fibers. In some embodiments, the incident light signal and the reflected light signals are transmitted between the console and the medical instrument via the interconnect. In some embodiments, wherein a portion of the interconnect includes a predetermined bend. 
     In other embodiments, the system further comprises an ultrasound probe coupled to the console via an ultrasound connection, wherein a portion of the interconnect that includes a predetermined bend is coupled to the ultrasound probe. In some embodiments, a length of the interconnect is collocated with the ultrasound connection. In yet other embodiments, the determination of the positioning and the orientation of the medical instrument is relative to the predetermined bend. 
     These and other features of the concepts provided herein will become more apparent to those of skill in the art in view of the accompanying drawings and following description, which disclose particular embodiments of such concepts in greater detail. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the disclosure are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: 
         FIG. 1A  is an illustrative embodiment of a medical instrument monitoring system including a medical instrument with optic shape sensing and fiber optic-based oximetry capabilities in accordance with some embodiments; 
         FIG. 1B  is an alternative illustrative embodiment of the medical instrument monitoring system  100  in accordance with some embodiments; 
         FIG. 2  is an exemplary embodiment of a structure of a section of the multi-core optical fiber included within the stylet  120  of  FIG. 1A  in accordance with some embodiments; 
         FIG. 3A  is a first exemplary embodiment of the stylet of  FIG. 1A  supporting both an optical and electrical signaling in accordance with some embodiments; 
         FIG. 3B  is a cross sectional view of the stylet of  FIG. 3A  in accordance with some embodiments; 
         FIG. 4A  is a second exemplary embodiment of the stylet of  FIG. 1B  in accordance with some embodiments; 
         FIG. 4B  is a cross sectional view of the stylet of  FIG. 4A  in accordance with some embodiments; 
         FIG. 5A  is an elevation view of a first illustrative embodiment of a catheter including integrated tubing, a diametrically disposed septum, and micro-lumens formed within the tubing and septum in accordance with some embodiments; 
         FIG. 5B  is a perspective view of the first illustrative embodiment of the catheter of  FIG. 5A  including core fibers installed within the micro-lumens in accordance with some embodiments; 
         FIGS. 6A-6B  are flowcharts of the methods of operations conducted by the medical instrument monitoring system of  FIGS. 1A-1B  to achieve optic 3D shape sensing in accordance with some embodiments; 
         FIG. 7  is an exemplary embodiment of the medical instrument monitoring system of  FIGS. 1A-1B  during operation and insertion of the catheter into a patient in accordance with some embodiments; 
         FIG. 8A  is an alternative embodiment of the medical instrument monitoring system of  FIGS. 1A-1B  including an optically-enabled needle during operation in accordance with some embodiments; 
         FIG. 8B  is a second exemplary embodiment of the medical instrument monitoring system of  FIG. 8A  during operation in accordance with some embodiments; 
         FIG. 8C  is a third exemplary embodiment of the medical instrument monitoring system of  FIG. 8A  during operation in accordance with some embodiments; 
         FIG. 9A  is a second alternative embodiment of the medical instrument monitoring system of  FIGS. 1A-1B  including an optically-enabled stylet within a needle during operation in accordance with some embodiments; 
         FIG. 9B  is a second exemplary embodiment of the medical instrument monitoring system of  FIG. 9A  during operation in accordance with some embodiments; 
         FIG. 10  is an illustration of the medical instrument monitoring system of  FIG. 8A  including a sterile drape during operation in accordance with some embodiments; 
         FIG. 11  is an illustration of the medical instrument monitoring system of  FIG. 8A  during use including an exemplary visualization rendered on a display in accordance with some embodiments; and 
         FIG. 12  is a flowchart of an exemplary methodology of inserting a medical instrument into a patient vasculature in accordance with some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Before some particular embodiments are disclosed in greater detail, it should be understood that the particular embodiments disclosed herein do not limit the scope of the concepts provided herein. It should also be understood that a particular embodiment disclosed herein can have features that can be readily separated from the particular embodiment and optionally combined with or substituted for features of any of a number of other embodiments disclosed herein. 
     Regarding terms used herein, it should also be understood the terms are for the purpose of describing some particular embodiments, and the terms do not limit the scope of the concepts provided herein. Ordinal numbers (e.g., first, second, third, etc.) are generally used to distinguish or identify different features or steps in a group of features or steps, and do not supply a serial or numerical limitation. For example, “first,” “second,” and “third” features or steps need not necessarily appear in that order, and the particular embodiments including such features or steps need not necessarily be limited to the three features or steps. Labels such as “left,” “right,” “top,” “bottom,” “front,” “back,” and the like are used for convenience and are not intended to imply, for example, any particular fixed location, orientation, or direction. Instead, such labels are used to reflect, for example, relative location, orientation, or directions. Singular forms of “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise. 
     With respect to “proximal,” a “proximal portion” or a “proximal end portion” of, for example, a probe disclosed herein includes a portion of the probe intended to be near a clinician when the probe is used on a patient. Likewise, a “proximal length” of, for example, the probe includes a length of the probe intended to be near the clinician when the probe is used on the patient. A “proximal end” of, for example, the probe includes an end of the probe intended to be near the clinician when the probe is used on the patient. The proximal portion, the proximal end portion, or the proximal length of the probe can include the proximal end of the probe; however, the proximal portion, the proximal end portion, or the proximal length of the probe need not include the proximal end of the probe. That is, unless context suggests otherwise, the proximal portion, the proximal end portion, or the proximal length of the probe is not a terminal portion or terminal length of the probe. 
     With respect to “distal,” a “distal portion” or a “distal end portion” of, for example, a probe disclosed herein includes a portion of the probe intended to be near or in a patient when the probe is used on the patient. Likewise, a “distal length” of, for example, the probe includes a length of the probe intended to be near or in the patient when the probe is used on the patient. A “distal end” of, for example, the probe includes an end of the probe intended to be near or in the patient when the probe is used on the patient. The distal portion, the distal end portion, or the distal length of the probe can include the distal end of the probe; however, the distal portion, the distal end portion, or the distal length of the probe need not include the distal end of the probe. That is, unless context suggests otherwise, the distal portion, the distal end portion, or the distal length of the probe is not a terminal portion or terminal length of the probe. 
     The term “logic” may be representative of hardware, firmware or software that is configured to perform one or more functions. As hardware, the term logic may refer to or include circuitry having data processing and/or storage functionality. Examples of such circuitry may include, but are not limited or restricted to a hardware processor (e.g., microprocessor, one or more processor cores, a digital signal processor, a programmable gate array, a microcontroller, an application specific integrated circuit “ASIC”, etc.), a semiconductor memory, or combinatorial elements. 
     Additionally, or in the alternative, the term logic may refer to or include software such as one or more processes, one or more instances, Application Programming Interface(s) (API), subroutine(s), function(s), applet(s), servlet(s), routine(s), source code, object code, shared library/dynamic link library (dll), or even one or more instructions. This software may be stored in any type of a suitable non-transitory storage medium, or transitory storage medium (e.g., electrical, optical, acoustical or other form of propagated signals such as carrier waves, infrared signals, or digital signals). Examples of a non-transitory storage medium may include, but are not limited or restricted to a programmable circuit; non-persistent storage such as volatile memory (e.g., any type of random access memory “RAM”); or persistent storage such as non-volatile memory (e.g., read-only memory “ROM”, power-backed RAM, flash memory, phase-change memory, etc.), a solid-state drive, hard disk drive, an optical disc drive, or a portable memory device. As firmware, the logic may be stored in persistent storage. 
     Referring to  FIG. 1A , an illustrative embodiment of a medical instrument monitoring system including a medical instrument with optic shape sensing and fiber optic-based oximetry capabilities is shown in accordance with some embodiments. As shown, the system  100  generally includes a console  110  and a stylet assembly  119  communicatively coupled to the console  110 . For this embodiment, the stylet assembly  119  includes an elongate probe (e.g., stylet)  120  on its distal end  122  and a console connector  133  on its proximal end  124 . The console connector  133  enables the stylet assembly  119  to be operably connected to the console  110  via an interconnect  145  including one or more optical fibers  147  (hereinafter, “optical fiber(s)”) and a conductive medium terminated by a single optical/electric connector  146  (or terminated by dual connectors. Herein, the connector  146  is configured to engage (mate) with the console connector  133  to allow for the propagation of light between the console  110  and the stylet assembly  119  as well as the propagation of electrical signals from the stylet  120  to the console  110 . 
     An exemplary implementation of the console  110  includes a processor  160 , a memory  165 , a display  170  and optical logic  180 , although it is appreciated that the console  110  can take one of a variety of forms and may include additional components (e.g., power supplies, ports, interfaces, etc.) that are not directed to aspects of the disclosure. An illustrative example of the console  110  is illustrated in U.S. Publication No. 2019/0237902, the entire contents of which are incorporated by reference herein. The processor  160 , with access to the memory  165  (e.g., non-volatile memory or non-transitory, computer-readable medium), is included to control functionality of the console  110  during operation. As shown, the display  170  may be a liquid crystal diode (LCD) display integrated into the console  110  and employed as a user interface to display information to the clinician, especially during a catheter placement procedure (e.g., cardiac catheterization). In another embodiment, the display  170  may be separate from the console  110 . Although not shown, a user interface is configured to provide user control of the console  110 . 
     For both of these embodiments, the content depicted by the display  170  may change according to which mode the stylet  120  is configured to operate: optical, TLS, ECG, or another modality. In TLS mode, the content rendered by the display  170  may constitute a two-dimensional (2D) or three-dimensional (3D) representation of the physical state (e.g., length, shape, form, and/or orientation) of the stylet  120  computed from characteristics of reflected light signals  150  returned to the console  110 . The reflected light signals  150  constitute light of a specific spectral width of broadband incident light  155  reflected back to the console  110 . According to one embodiment of the disclosure, the reflected light signals  150  may pertain to various discrete portions (e.g., specific spectral widths) of broadband incident light  155  transmitted from and sourced by the optical logic  180 , as described below 
     According to one embodiment of the disclosure, an activation control  126 , included on the stylet assembly  119 , may be used to set the stylet  120  into a desired operating mode and selectively alter operability of the display  170  by the clinician to assist in medical device placement. For example, based on the modality of the stylet  120 , the display  170  of the console  110  can be employed for optical modality-based guidance during catheter advancement through the vasculature or TLS modality to determine the physical state (e.g., length, form, shape, orientation, etc.) of the stylet  120 . In one embodiment, information from multiple modes, such as optical, TLS or ECG for example, may be displayed concurrently (e.g., at least partially overlapping in time). 
     Referring still to  FIG. 1A , the optical logic  180  is configured to support operability of the stylet assembly  119  and enable the return of information to the console  110 , which may be used to determine the physical state associated with the stylet  120  along with monitored electrical signals such as ECG signaling via an electrical signaling logic  181  that supports receipt and processing of the received electrical signals from the stylet  120  (e.g., ports, analog-to-digital conversion logic, etc.). The physical state of the stylet  120  may be based on changes in characteristics of the reflected light signals  150  received at the console  110  from the stylet  120 . The characteristics may include shifts in wavelength caused by strain on certain regions of the core fibers integrated within an optical fiber core  135  positioned within or operating as the stylet  120 , as shown below. As discussed herein, the optical fiber core  135  may be comprised of core fibers  137   1 - 137   M  (M=1 for a single core, and M≥2 for a multi-core), where the core fibers  137   1 - 137   M  may collectively be referred to as core fiber(s)  137 . Unless otherwise specified or the instant embodiment requires an alternative interpretation, embodiments discussed herein will refer to a multi-core optical fiber  135 . From information associated with the reflected light signals  150 , the console  110  may determine (through computation or extrapolation of the wavelength shifts) the physical state of the stylet  120 , and also that of a catheter  195  configured to receive the stylet  120 . 
     According to one embodiment of the disclosure, as shown in  FIG. 1A , the optical logic  180  may include a light source  182  and an optical receiver  184 . The light source  182  is configured to transmit the incident light  155  (e.g., broadband) for propagation over the optical fiber(s)  147  included in the interconnect  145 , which are optically connected to the multi-core optical fiber core  135  within the stylet  120 . In one embodiment, the light source  182  is a tunable swept laser, although other suitable light sources can also be employed in addition to a laser, including semi-coherent light sources, LED light sources, etc. 
     The optical receiver  184  is configured to: (i) receive returned optical signals, namely reflected light signals  150  received from optical fiber-based reflective gratings (sensors) fabricated within each core fiber of the multi-core optical fiber  135  deployed within the stylet  120 , and (ii) translate the reflected light signals  150  into reflection data  192 , namely data in the form of electrical signals representative of the reflected light signals including wavelength shifts caused by strain. The reflected light signals  150  associated with different spectral widths may include reflected light signals  151  provided from sensors positioned in the center core fiber (reference) of the multi-core optical fiber  135  and reflected light signals  152  provided from sensors positioned in the periphery core fibers of the multi-core optical fiber  135 , as described below. Herein, the optical receiver  184  may be implemented as a photodetector, such as a positive-intrinsic-negative “PIN” photodiode, avalanche photodiode, or the like. 
     As shown, both the light source  182  and the optical receiver  184  are operably connected to the processor  160 , which governs their operation. Also, the optical receiver  184  is operably coupled to provide the reflection data  192  to the memory  165  for storage and processing by reflection data classification logic  190 . The reflection data classification logic  190  may be configured to: (i) identify which core fibers pertain to which of the received reflection data  192  and (ii) segregate the reflection data  192  provided from reflected light signals  150  pertaining to similar regions of the stylet  120  or spectral widths into analysis groups. The reflection data for each analysis group is made available to shape sensing analytic logic  194  for analytics. 
     According to one embodiment of the disclosure, the shape sensing analytic logic  194  is configured to compare wavelength shifts measured by sensors deployed in each periphery core fiber at the same measurement region of the stylet  120  (or same spectral width) to the wavelength shift at a center core fiber of the multi-core optical fiber  135  positioned along central axis and operating as a neutral axis of bending. From these analytics, the shape sensing analytic logic  194  may determine the shape the core fibers have taken in 3D space and may further determine the current physical state of the catheter  195  in 3D space for rendering on the display  170 . 
     According to one embodiment of the disclosure, the shape sensing analytic logic  194  may generate a rendering of the current physical state of the stylet  120  (and potentially the catheter  195 ), based on heuristics or run-time analytics. For example, the shape sensing analytic logic  194  may be configured in accordance with machine-learning techniques to access a data store (library) with pre-stored data (e.g., images, etc.) pertaining to different regions of the stylet  120  (or catheter  195 ) in which reflected light from core fibers have previously experienced similar or identical wavelength shifts. From the pre-stored data, the current physical state of the stylet  120  (or catheter  195 ) may be rendered. Alternatively, as another example, the shape sensing analytic logic  194  may be configured to determine, during run-time, changes in the physical state of each region of the multi-core optical fiber  135  based on at least: (i) resultant wavelength shifts experienced by different core fibers within the optical fiber  135 , and (ii) the relationship of these wavelength shifts generated by sensors positioned along different periphery core fibers at the same cross-sectional region of the multi-core optical fiber  135  to the wavelength shift generated by a sensor of the center core fiber at the same cross-sectional region. It is contemplated that other processes and procedures may be performed to utilize the wavelength shifts as measured by sensors along each of the core fibers within the multi-core optical fiber  135  to render appropriate changes in the physical state of the stylet  120  (and/or catheter  195 ), especially to enable guidance of the stylet  120 , when positioned at a distal tip of the catheter  195 , within the vasculature of the patient and at a desired destination within the body. 
     The console  110  may further include electrical signaling logic  181 , which is positioned to receive one or more electrical signals from the stylet  120 . The stylet  120  is configured to support both optical connectivity as well as electrical connectivity. The electrical signaling logic  181  receives the electrical signals (e.g., ECG signals) from the stylet  120  via the conductive medium. The electrical signals may be processed by electrical signal analytic logic  196 , executed by the processor  160 , to determine ECG waveforms for display. 
     Referring to  FIG. 1B , an alternative exemplary embodiment of a medical instrument monitoring system  100  is shown. Herein, the medical instrument monitoring system  100  features a console  110  and a medical instrument  130  communicatively coupled to the console  110 . For this embodiment, the medical instrument  130  corresponds to a catheter, which features an integrated tubing with two or more lumen extending between a proximal end  131  and a distal end  132  of the integrated tubing. The integrated tubing (sometimes referred to as “catheter tubing”) is in communication with one or more extension legs  140  via a bifurcation hub  142 . An optical-based catheter connector  144  may be included on a proximal end of at least one of the extension legs  140  to enable the catheter  130  to operably connect to the console  110  via an interconnect  145  or another suitable component. Herein, the interconnect  145  may include a connector  146  that, when coupled to the optical-based catheter connector  144 , establishes optical connectivity between one or more optical fibers  147  (hereinafter, “optical fiber(s)”) included as part of the interconnect  145  and core fibers  137  deployed within the catheter  130  and integrated into the tubing. Alternatively, a different combination of connectors, including one or more adapters, may be used to optically connect the optical fiber(s)  147  to the core fibers  137  within the catheter  130 . The core fibers  137  deployed within the catheter  130  as illustrated in  FIG. 1B  include the same characteristics and perform the same functionalities as the core fibers  137  deployed within the stylet  120  of  FIG. 1A . 
     The optical logic  180  is configured to support graphical rendering of the catheter  130 , most notably the integrated tubing of the catheter  130 , based on characteristics of the reflected light signals  150  received from the catheter  130 . The characteristics may include shifts in wavelength caused by strain on certain regions of the core fibers  137  integrated within (or along) a wall of the integrated tubing, which may be used to determine (through computation or extrapolation of the wavelength shifts) the physical state of the catheter  130 , notably its integrated tubing or a portion of the integrated tubing such as a tip or distal end of the tubing to read fluctuations (real-time movement) of the tip (or distal end). 
     More specifically, the optical logic  180  includes a light source  182 . The light source  182  is configured to transmit the broadband incident light  155  for propagation over the optical fiber(s)  147  included in the interconnect  145 , which are optically connected to multiple core fibers  137  within the catheter tubing. Herein, the optical receiver  184  is configured to: (i) receive returned optical signals, namely reflected light signals  150  received from optical fiber-based reflective gratings (sensors) fabricated within each of the core fibers  137  deployed within the catheter  130 , and (ii) translate the reflected light signals  150  into reflection data  192 , namely data in the form of electrical signals representative of the reflected light signals including wavelength shifts caused by strain. The reflected light signals  150  associated with different spectral widths include reflected light signals  151  provided from sensors positioned in the center core fiber (reference) of the catheter  130  and reflected light signals  152  provided from sensors positioned in the outer core fibers of the catheter  130 , as described below. 
     As noted above, the shape sensing logic  194  is configured to compare wavelength shifts measured by sensors deployed in each outer core fiber at the same measurement region of the catheter (or same spectral width) to the wavelength shift at the center core fiber positioned along central axis and operating as a neutral axis of bending. From these analytics, the shape sensing logic  190  may determine the shape the core fibers have taken in 3D space and may further determine the current physical state of the catheter  130  in 3D space for rendering on the display  170 . 
     According to one embodiment of the disclosure, the shape sensing logic  194  may generate a rendering of the current physical state of the catheter  130 , especially the integrated tubing, based on heuristics or run-time analytics. For example, the shape sensing logic  194  may be configured in accordance with machine-learning techniques to access a data store (library) with pre-stored data (e.g., images, etc.) pertaining to different regions of the catheter  130  in which the core fibers  137  experienced similar or identical wavelength shifts. From the pre-stored data, the current physical state of the catheter  130  may be rendered. Alternatively, as another example, the shape sensing logic  194  may be configured to determine, during run-time, changes in the physical state of each region of the catheter  130 , notably the tubing, based on at least (i) resultant wavelength shifts experienced by the core fibers  137  and (ii) the relationship of these wavelength shifts generated by sensors positioned along different outer core fibers at the same cross-sectional region of the catheter  130  to the wavelength shift generated by a sensor of the center core fiber at the same cross-sectional region. It is contemplated that other processes and procedures may be performed to utilize the wavelength shifts as measured by sensors along each of the core fibers  137  to render appropriate changes in the physical state of the catheter  130 . 
     Referring to  FIG. 2 , an exemplary embodiment of a structure of a section of the multi-core optical fiber included within the stylet  120  of  FIG. 1A  is shown in accordance with some embodiments. The multi-core optical fiber section  200  of the multi-core optical fiber  135  depicts certain core fibers  137   1 - 137   M  (M≥2, M=4 as shown, see  FIG. 3A ) along with the spatial relationship between sensors (e.g., reflective gratings)  210   11 - 210   NM  (N≥2; M≥2) present within the core fibers  137   1 - 137   M , respectively. As noted above, the core fibers  137   1 - 137   M  may be collectively referred to as “the core fibers  137 .” 
     As shown, the section  200  is subdivided into a plurality of cross-sectional regions  220   1 - 220   N , where each cross-sectional region  220   1 - 220   N  corresponds to reflective gratings  210   11 - 210   14  . . .  210   N1 - 210   N4 . Some or all of the cross-sectional regions  220   1  . . .  220   N  may be static (e.g., prescribed length) or may be dynamic (e.g., vary in size among the regions  220   1  . . .  220   N ). A first core fiber  137   1  is positioned substantially along a center (neutral) axis  230  while core fiber  137   2  may be oriented within the cladding of the multi-core optical fiber  135 , from a cross-sectional, front-facing perspective, to be position on “top” the first core fiber  137   1 . In this deployment, the core fibers  137   3  and  137   4  may be positioned “bottom left” and “bottom right” of the first core fiber  137   1 . As examples,  FIGS. 3A-4B  provides illustrations of such. 
     Referencing the first core fiber  137   1  as an illustrative example, when the stylet  120  is operative, each of the reflective gratings  210   1 - 210   N  reflects light for a different spectral width. As shown, each of the gratings  210   1i - 210   Ni  (1≤i≤M) is associated with a different, specific spectral width, which would be represented by different center frequencies of f 1  . . . f N , where neighboring spectral widths reflected by neighboring gratings are non-overlapping according to one embodiment of the disclosure. 
     Herein, positioned in different core fibers  137   2 - 137   3  but along at the same cross-sectional regions  220 - 220   N  of the multi-core optical fiber  135 , the gratings  210   12 - 210   N2  and  210   13 - 210   N3  are configured to reflect incoming light at same (or substantially similar) center frequency. As a result, the reflected light returns information that allows for a determination of the physical state of the optical fibers  137  (and the stylet  120 ) based on wavelength shifts measured from the returned, reflected light. In particular, strain (e.g., compression or tension) applied to the multi-core optical fiber  135  (e.g., at least core fibers  137   2 - 137   3 ) results in wavelength shifts associated with the returned, reflected light. Based on different locations, the core fibers  137   1 - 137   4  experience different types and degree of strain based on angular path changes as the stylet  120  advances in the patient. 
     For example, with respect to the multi-core optical fiber section  200  of  FIG. 2 , in response to angular (e.g., radial) movement of the stylet  120  is in the left-veering direction, the fourth core fiber  137   4  (see  FIG. 3A ) of the multi-core optical fiber  135  with the shortest radius during movement (e.g., core fiber closest to a direction of angular change) would exhibit compression (e.g., forces to shorten length). At the same time, the third core fiber  137   3  with the longest radius during movement (e.g., core fiber furthest from the direction of angular change) would exhibit tension (e.g., forces to increase length). As these forces are different and unequal, the reflected light from reflective gratings  210   N2  and  210   N3  associated with the core fiber  137   2  and  137   3  will exhibit different changes in wavelength. The differences in wavelength shift of the reflected light signals  150  can be used to extrapolate the physical configuration of the stylet  120  by determining the degrees of wavelength change caused by compression/tension for each of the periphery fibers (e.g., the second core fiber  137   2  and the third core fiber  137   3 ) in comparison to the wavelength of the reference core fiber (e.g., first core fiber  137   1 ) located along the neutral axis  230  of the multi-core optical fiber  135 . These degrees of wavelength change may be used to extrapolate the physical state of the stylet  120 . The reflected light signals  150  are reflected back to the console  110  via individual paths over a particular core fiber  137   1 - 137   M . 
     Referring to  FIG. 3A , a first exemplary embodiment of the stylet of  FIG. 1A  supporting both an optical and electrical signaling is shown in accordance with some embodiments. Herein, the stylet  120  features a centrally located multi-core optical fiber  135 , which includes a cladding  300  and a plurality of core fibers  137   1 - 137   M  (M≥2; M=4) residing within a corresponding plurality of lumens  320   1 - 320   M . While the multi-core optical fiber  135  is illustrated within four (4) core fibers  137   1 - 137   4 , a greater number of core fibers  137   1 - 137   M  (M&gt;4) may be deployed to provide a more detailed three-dimensional sensing of the physical state (e.g., shape, etc.) of the multi-core optical fiber  135  and the stylet  120  deploying the optical fiber  135 . 
     For this embodiment of the disclosure, the multi-core optical fiber  135  is encapsulated within a concentric braided tubing  310  positioned over a low coefficient of friction layer  335 . The braided tubing  310  may feature a “mesh” construction, in which the spacing between the intersecting conductive elements is selected based on the degree of rigidity desired for the stylet  120 , as a greater spacing may provide a lesser rigidity, and thereby, a more pliable stylet  120 . 
     According to this embodiment of the disclosure, as shown in  FIGS. 3A-3B , the core fibers  137   1 - 137   4  include (i) a central core fiber  137   1  and (ii) a plurality of periphery core fibers  137   2 - 137   4 , which are maintained within lumens  320   1 - 320   4  formed in the cladding  300 . According to one embodiment of the disclosure, one or more of the lumen  320   1 - 320   4  may be configured with a diameter sized to be greater than the diameter of the core fibers  137   1 - 137   4 . By avoiding a majority of the surface area of the core fibers  137   1 - 137   4  from being in direct physical contact with a wall surface of the lumens  320   1 - 320   4 , the wavelength changes to the incident light are caused by angular deviations in the multi-core optical fiber  135  thereby reducing influence of compression and tension forces being applied to the walls of the lumens  320   1 - 320   M , not the core fibers  137   1 - 137   M  themselves. 
     As further shown in  FIGS. 3A-3B , the core fibers  137   1 - 137   4  may include central core fiber  137   1  residing within a first lumen  320   1  formed along the first neutral axis  230  and a plurality of core fibers  137   2 - 137   4  residing within lumens  320   2 - 320   4  each formed within different areas of the cladding  300  radiating from the first neutral axis  230 . In general, the core fibers  137   2 - 137   4 , exclusive of the central core fiber  137   1 , may be positioned at different areas within a cross-sectional area  305  of the cladding  300  to provide sufficient separation to enable three-dimensional sensing of the multi-core optical fiber  135  based on changes in wavelength of incident light propagating through the core fibers  137   2 - 137   4  and reflected back to the console for analysis. 
     For example, where the cladding  300  features a circular cross-sectional area  305  as shown in  FIG. 3B , the core fibers  137   2 - 137   4  may be positioned substantially equidistant from each other as measured along a perimeter of the cladding  300 , such as at “top” (12 o&#39;clock), “bottom-left” (8 o&#39;clock) and “bottom-right” (4 o&#39;clock) locations as shown. Hence, in general terms, the core fibers  137   2 - 137   4  may be positioned within different segments of the cross-sectional area  305 . Where the cross-sectional area  305  of the cladding  300  has a distal tip  330  and features a polygon cross-sectional shape (e.g., triangular, square, rectangular, pentagon, hexagon, octagon, etc.), the central core fiber  137   1  may be located at or near a center of the polygon shape, while the remaining core fibers  137   2 - 137   M  may be located proximate to angles between intersecting sides of the polygon shape. 
     Referring still to  FIGS. 3A-3B , operating as the conductive medium for the stylet  120 , the braided tubing  310  provides mechanical integrity to the multi-core optical fiber  135  and operates as a conductive pathway for electrical signals. For example, the braided tubing  310  may be exposed to a distal tip of the stylet  120 . The cladding  300  and the braided tubing  310 , which is positioned concentrically surrounding a circumference of the cladding  300 , are contained within the same insulating layer  350 . The insulating layer  350  may be a sheath or conduit made of protective, insulating (e.g., non-conductive) material that encapsulates both for the cladding  300  and the braided tubing  310 , as shown. 
     Referring to  FIG. 4A , a second exemplary embodiment of the stylet of  FIG. 1B  is shown in accordance with some embodiments. Referring now to  FIG. 4A , a second exemplary embodiment of the stylet  120  of  FIG. 1B  supporting both an optical and electrical signaling is shown. Herein, the stylet  120  features the multi-core optical fiber  135  described above and shown in  FIG. 3A , which includes the cladding  300  and the first plurality of core fibers  137   1 - 137   M  (M≥3; M=4 for embodiment) residing within the corresponding plurality of lumens  320   1 - 320   M . For this embodiment of the disclosure, the multi-core optical fiber  135  includes the central core fiber  137   1  residing within the first lumen  320   1  formed along the first neutral axis  230  and the second plurality of core fibers  137   2 - 137   4  residing within corresponding lumens  320   2 - 320   4  positioned in different segments within the cross-sectional area  305  of the cladding  300 . Herein, the multi-core optical fiber  135  is encapsulated within a conductive tubing  400 . The conductive tubing  400  may feature a “hollow” conductive cylindrical member concentrically encapsulating the multi-core optical fiber  135 . 
     Referring to  FIGS. 4A-4B , operating as a conductive medium for the stylet  120  in the transfer of electrical signals (e.g., ECG signals) to the console, the conductive tubing  400  may be exposed up to a tip  410  of the stylet  120 . For this embodiment of the disclosure, a conductive epoxy  420  (e.g., metal-based epoxy such as a silver epoxy) may be affixed to the tip  410  and similarly joined with a termination/connection point created at a proximal end  430  of the stylet  120 . The cladding  300  and the conductive tubing  400 , which is positioned concentrically surrounding a circumference of the cladding  300 , are contained within the same insulating layer  440 . The insulating layer  440  may be a protective conduit encapsulating both for the cladding  300  and the conductive tubing  400 , as shown. 
     Referring to  FIG. 5A , an elevation view of a first illustrative embodiment of a catheter including integrated tubing, a diametrically disposed septum, and micro-lumens formed within the tubing and septum is shown in accordance with some embodiments. Herein, the catheter  130  includes integrated tubing, the diametrically disposed septum  510 , and the plurality of micro-lumens  530   1 - 530   4  which, for this embodiment, are fabricated to reside within the wall  500  of the integrated tubing of the catheter  130  and within the septum  510 . In particular, the septum  510  separates a single lumen, formed by the inner surface  505  of the wall  500  of the catheter  130 , into multiple lumen, namely two lumens  540  and  545  as shown. Herein, the first lumen  540  is formed between a first arc-shaped portion  535  of the inner surface  505  of the wall  500  forming the catheter  130  and a first outer surface  555  of the septum  510  extending longitudinally within the catheter  130 . The second lumen  545  is formed between a second arc-shaped portion  565  of the inner surface  505  of the wall  500  forming the catheter  130  and a second outer surfaces  560  of the septum  510 . 
     According to one embodiment of the disclosure, the two lumens  540  and  545  have approximately the same volume. However, the septum  510  need not separate the tubing into two equal lumens. For example, instead of the septum  510  extending vertically (12 o&#39;clock to 6 o&#39;clock) from a front-facing, cross-sectional perspective of the tubing, the septum  510  could extend horizontally (3 o&#39;clock to 9 o&#39;clock), diagonally (1 o&#39;clock to 7 o&#39;clock; 10 o&#39;clock to 4 o&#39;clock) or angularly (2 o&#39;clock to 10 o&#39;clock). In the later configuration, each of the lumens  540  and  545  of the catheter  130  would have a different volume. 
     With respect to the plurality of micro-lumens  530   1 - 530   4 , the first micro-lumen  530   1  is fabricated within the septum  510  at or near the cross-sectional center  525  of the integrated tubing. For this embodiment, three micro-lumens  530   2 - 530   4  are fabricated to reside within the wall  500  of the catheter  130 . In particular, a second micro-lumen  530   2  is fabricated within the wall  500  of the catheter  130 , namely between the inner surface  505  and outer surface  507  of the first arc-shaped portion  535  of the wall  500 . Similarly, the third micro-lumen  530   3  is also fabricated within the wall  500  of the catheter  130 , namely between the inner and outer surfaces  505 / 507  of the second arc-shaped portion  555  of the wall  500 . The fourth micro-lumen  530   4  is also fabricated within the inner and outer surfaces  505 / 507  of the wall  500  that are aligned with the septum  510 . 
     According to one embodiment of the disclosure, as shown in  FIG. 5A , the micro-lumens  530   2 - 530   4  are positioned in accordance with a “top-left” (10 o&#39;clock), “top-right” (2 o&#39;clock) and “bottom” (6 o&#39;clock) layout from a front-facing, cross-sectional perspective. Of course, the micro-lumens  530   2 - 530   4  may be positioned differently, provided that the micro-lumens  530   2 - 530   4  are spatially separated along the circumference  520  of the catheter  130  to ensure a more robust collection of reflected light signals from the outer core fibers  570   2 - 570   4  when installed. For example, two or more of micro-lumens (e.g., micro-lumens  530   2  and  530   4 ) may be positioned at different quadrants along the circumference  520  of the catheter wall  500 . 
     Referring to  FIG. 5B , a perspective view of the first illustrative embodiment of the catheter of  FIG. 5A  including core fibers installed within the micro-lumens is shown in accordance with some embodiments. According to one embodiment of the disclosure, the second plurality of micro-lumens  530   2 - 530   4  are sized to retain corresponding outer core fibers  570   2 - 570   4 , where the diameter of each of the second plurality of micro-lumens  530   2 - 530   4  may be sized just larger than the diameters of the outer core fibers  570   2 - 570   4 . The size differences between a diameter of a single core fiber and a diameter of any of the micro-lumen  530   1 - 530   4  may range between 0.001 micrometers (μm) and 1000 μm, for example. As a result, the cross-sectional areas of the outer core fibers  570   2 - 570   4  would be less than the cross-sectional areas of the corresponding micro-lumens  530   2 - 530   4 . A “larger” micro-lumen (e.g., micro-lumen  530   2 ) may better isolate external strain being applied to the outer core fiber  570   2  from strain directly applied to the catheter  130  itself. Similarly, the first micro-lumen  530   1  may be sized to retain the center core fiber  570   1 , where the diameter of the first micro-lumen  530   1  may be sized just larger than the diameter of the center core fiber  570   1 . 
     As an alternative embodiment of the disclosure, one or more of the micro-lumens  530   1 - 530   4  may be sized with a diameter that exceeds the diameter of the corresponding one or more core fibers  570   1 - 570   4 . However, at least one of the micro-lumens  530   1 - 530   4  is sized to fixedly retain their corresponding core fiber (e.g., core fiber retained with no spacing between its lateral surface and the interior wall surface of its corresponding micro-lumen). As yet another alternative embodiment of the disclosure, all the micro-lumens  530   1 - 530   4  are sized with a diameter to fixedly retain the core fibers  570   1 - 570   4 . 
     Referring to  FIGS. 6A-6B , flowcharts of methods of operations conducted by the medical instrument monitoring system of  FIGS. 1A-1B  to achieve optic 3D shape sensing are shown in accordance with some embodiments. Herein, the catheter includes at least one septum spanning across a diameter of the tubing wall and continuing longitudinally to subdivide the tubing wall. The medial portion of the septum is fabricated with a first micro-lumen, where the first micro-lumen is coaxial with the central axis of the catheter tubing. The first micro-lumen is configured to retain a center core fiber. Two or more micro-lumen, other than the first micro-lumen, are positioned at different locations circumferentially spaced along the wall of the catheter tubing. For example, two or more of the second plurality of micro-lumens may be positioned at different quadrants along the circumference of the catheter wall. 
     Furthermore, each core fiber includes a plurality of sensors spatially distributed along its length between at least the proximal and distal ends of the catheter tubing. This array of sensors is distributed to position sensors at different regions of the core fiber to enable distributed measurements of strain throughout the entire length or a selected portion of the catheter tubing. These distributed measurements may be conveyed through reflected light of different spectral widths (e.g., specific wavelength or specific wavelength ranges) that undergoes certain wavelength shifts based on the type and degree of strain. 
     According to one embodiment of the disclosure, as shown in  FIG. 6A , for each core fiber, broadband incident light is supplied to propagate through a particular core fiber (block  600 ). Unless discharged, upon the incident light reaching a sensor of a distributed array of sensors measuring strain on a particular core fiber, light of a prescribed spectral width associated with the first sensor is to be reflected back to an optical receiver within a console (blocks  605 - 610 ). Herein, the sensor alters characteristics of the reflected light signal to identify the type and degree of strain on the particular core fiber as measured by the first sensor (blocks  615 - 620 ). According to one embodiment of the disclosure, the alteration in characteristics of the reflected light signal may signify a change (shift) in the wavelength of the reflected light signal from the wavelength of the incident light signal associated with the prescribed spectral width. The sensor returns the reflected light signal over the core fiber and the remaining spectrum of the incident light continues propagation through the core fiber toward a distal end of the catheter tubing (blocks  625 - 630 ). The remaining spectrum of the incident light may encounter other sensors of the distributed array of sensors, where each of these sensors would operate as set forth in blocks  605 - 630  until the last sensor of the distributed array of sensors returns the reflected light signal associated with its assigned spectral width and the remaining spectrum is discharged as illumination. 
     Referring now to  FIG. 6B , during operation, multiple reflected light signals are returned to the console from each of the plurality of core fibers residing within the corresponding plurality of micro-lumens formed within a catheter, such as the catheter of  FIG. 1B . In particular, the optical receiver receives reflected light signals from the distributed arrays of sensors located on the center core fiber and the outer core fibers and translates the reflected light signals into reflection data, namely electrical signals representative of the reflected light signals including wavelength shifts caused by strain (blocks  650 - 655 ). The reflection data classification logic is configured to identify which core fibers pertain to which reflection data and segregate reflection data provided from reflected light signals pertaining to a particular measurement region (or similar spectral width) into analysis groups (block  660 - 665 ). 
     Each analysis group of reflection data is provided to shape sensing logic for analytics (block  670 ). Herein, the shape sensing logic compares wavelength shifts at each outer core fiber with the wavelength shift at the center core fiber positioned along central axis and operating as a neutral axis of bending (block  675 ). From this analytics, on all analytic groups (e.g., reflected light signals from sensors in all or most of the core fibers), the shape sensing logic may determine the shape the core fibers have taken in three-dimensional space, from which the shape sensing logic can determine the current physical state of the catheter in three-dimension space (blocks  680 - 685 ). 
     Referring to  FIG. 7 , an exemplary embodiment of the medical instrument monitoring system of  FIG. 1B  during operation and insertion of the catheter into a patient are shown in accordance with some embodiments. Herein, the catheter  130  generally includes the integrated tubing of the catheter  130  with a proximal portion  720  that generally remains exterior to the patient  700  and a distal portion  730  that generally resides within the patient vasculature after placement is complete. The (integrated) catheter tubing of the catheter  130  may be advanced to a desired position within the patient vasculature such as a distal end (or tip)  735  of the catheter tubing of the catheter  130  is proximate the patient&#39;s heart, such as in the lower one-third (⅓) portion of the Superior Vena Cava (“SVC”) for example. In some embodiments, various instruments may be disposed at the distal end  735  of the catheter  130  to measure pressure of blood in a certain heart chamber and in the blood vessels, view an interior of blood vessels, or the like. In alternative embodiments, such as those that utilize the stylet assembly of  FIG. 1A  and the catheter  195 , such instruments may be disposed at a distal end of the stylet  120 . 
     During advancement through a patient vasculature, the catheter tubing of the catheter  130  receives broadband incident light  155  from the console  110  via optical fiber(s)  147  within the interconnect  145 , where the incident light  155  propagates along the core fibers  137  of the multi-core optical fiber  135  within the catheter tubing of the catheter  130 . According to one embodiment of the disclosure, the connector  146  of the interconnect  145  terminating the optical fiber(s)  147  may be coupled to the optical-based catheter connector  144 , which may be configured to terminate the core fibers  137  deployed within the catheter  130 . Such coupling optically connects the core fibers  137  of the catheter  130  with the optical fiber(s)  147  within the interconnect  145 . The optical connectivity is needed to propagate the incident light  155  to the core fibers  137  and return the reflected light signals  150  to the optical logic  180  within the console  110  over the interconnect  145 . As described below in detail, the physical state of the catheter  130  may be ascertained based on analytics of the wavelength shifts of the reflected light signals  150 . 
     Referring now to  FIG. 8A , an alternative embodiment of the medical instrument monitoring system of  FIGS. 1A-1B  including an optically-enabled needle during operation is shown in accordance with some embodiments. Herein, the medical instrument monitoring system  800  includes the optically-enabled needle  801 , which includes Bragg fiber gratings  802  at a distal end. For example, the gratings  802  may be integrated directly on an inner wall of the lumen of the needle  801 . The gratings  802  provide numerous advantages including the ability to obtain measurements of the consistency of patient tissue (e.g., via strain experienced by the gratings  802  during insertion and advancement toward a blood vessel). 
     Further, a proximal end of the needle  801  includes a needle-based optical connector  804  that is configured to couple with an optical connector  808  disposed at a distal end of an interconnect  805  which includes an optical fiber  806 . The optical fiber  806  may be a multi-core optical fiber and include one or more core fibers  807   1 - 807   P  (collectively, “core fibers  807 ” and having the properties and capabilities of the core fibers  137  discussed herein). The optical fiber  806  also includes an optical connector  810  at its proximal end that is configured to couple with the connector  146  interconnect  145 , which couples to the console  110 . The interconnect  145  houses the optical fiber  147 , as noted above. Thus, optical signals, e.g., incident light and reflected light, may be transmitted between the console  110  and the needle  801 . The medical instrument monitoring system  800  of  FIG. 8A  further includes an ultrasound probe  812  configured to obtain ultrasound imaging data of an imaging area  816 , where the ultrasound imaging data may be provided to the console  110  via the electrical/ultrasound connection  818 . 
     In particular, in the embodiment illustrated, the optical fiber  806  is coupled (or otherwise secured) to the probe  812  via the securement mechanism  814 , which may include one or more straps (e.g., elastic or otherwise) or adhesive strips (e.g., medical tape). The optical fiber  806  is coupled to the probe  812  in such a manner so as to create a bend or kink (referred to herein as “bend  820 ”) in the optical fiber  806 . The bend  820  causes a consistent strain on the gratings of a particular section of core fibers  807 , thereby providing a consistent wavelength shift of the reflected light. As a result, the shape sensing logic  194  may receive reflected light and detect the positioning along the optical fiber  806  at which point the bend  820  occurs. The shape sensing logic  194  may then utilize the position of the bend  820  as a reference point in determining a positioning, location and/or orientation of the needle  801 . In one embodiment, when determining the positioning, location and/or orientation of the needle  801 , the bend  820  may serve as a point of origin. Thus, the positioning, location and/or orientation of the needle  801  may be determined with respect to the probe  812 . 
     Thus, the medical instrument monitoring system  800  may obtain ultrasound image data of the imaging area  816  from the probe  812  and additionally determine needle tracking information based on the reflected light. The bend  820  serves as a reference point in determining a positioning of the needle  801 , and particularly a distal tip of the needle  801 , relative to the probe  812 . The needle tracking information may then be displayed as an overlay to the ultrasound image data as displayed on display  170  of the console  110 . 
     Referring to  FIG. 8B , a second exemplary embodiment of the medical instrument monitoring system of  FIG. 8A  during operation is shown in accordance with some embodiments.  FIG. 8B  illustrates the medical instrument monitoring system  800  including the optically-enabled needle  801  of  FIG. 8A , which includes Bragg fiber gratings  802  at a distal end and the needle-based optical connector  804  that is configured to couple with an optical connector  808  of the interconnect  805 . 
     In contrast to the embodiment of  FIG. 8A , the embodiment illustrated, in  FIG. 8B  discloses the interconnect  805  (and thus the core fiber  806 ) coupled, or otherwise secured, to the patient  700  via a securement mechanism  824 , which may include one or more adhesive strips or patches (e.g., medical tape, etc.) or adjustable straps. The interconnect  805  is coupled to the patient  700  in such a manner so as to create a bend or kink (referred to herein as “bend  822 ”) in the optical fiber  806 . Like the bend  820  of  FIG. 8A , the bend  822  causes a consistent strain on the gratings of a particular section of core fibers  807 , which provides a consistent wavelength shift of the reflected light. As a result, the shape sensing logic  194  may receive reflected light and detect the positioning along the optical fiber  806  at which point the bend  822  occurs and can further utilize the position of the bend  822  as a reference point in determining a positioning, location and/or orientation of the needle  801 . 
     Thus, medical instrument monitoring system  100  may obtain ultrasound image data of the imaging area  816  from the probe  812  and additionally determine needle tracking information based on the reflected light. The bend  822  serves as a reference point in determining a positioning of the needle  801 , and particularly a distal tip of the needle  801 , relative to the patient  700 . The needle tracking information may then be displayed as an overlay to the ultrasound image data as displayed on display  170  of the console  110 . 
     Referring now to  FIG. 8C , a third exemplary embodiment of the medical instrument monitoring system of  FIG. 8A  during operation is shown in accordance with some embodiments. The embodiment of  FIG. 8C  illustrates that the interconnect  145  may include a predetermined bend  826  at its distal end. Further, the interconnect  145  may be coupled (or otherwise secured) to the probe  812  via the securement mechanism  814 , as discussed above. In some embodiments, the interconnect  145  may be manufactured with the predetermined bend  826  as shown in  FIG. 8C . However, as shown in other embodiments, a predetermined bend may be formed as a result of the coupling of an interconnect to the probe  812  or patient  700 . Further,  FIG. 8C  illustrates that at least a length of the interconnect  145  be may collocated with the electrical/ultrasound connection  818 . 
     Referring now to  FIG. 9A , a second alternative embodiment of the medical instrument monitoring system of  FIGS. 1A-1B  including an optically-enabled stylet within a needle during operation is shown in accordance with some embodiments. Herein, the medical instrument monitoring system  900  includes a needle  901  one or more lumens, within which a stylet  906  is disposed. 
     The stylet  906  may be a component of a stylet assembly that is may be similar in form to and perform similar functionalities as the stylet assembly  119  discussed above. For instance, the stylet  906  may be similar in form to and perform similar functionalities as the stylet  120 . In particular, the stylet  906  may include an optical fiber  135  having core fibers  137  disposed therein, such that the physical state of the stylet  906  may be based on changes in characteristics of reflected light signals  150  received at the console from the optical fiber of stylet  906 . The characteristics may include shifts in wavelength caused by strain on certain regions of the core fibers integrated within an optical fiber core  135  positioned within the stylet  906 . From information associated with the reflected light signals  150 , the console  110  may determine (through computation or extrapolation of the wavelength shifts) the physical state, such as positioning, location and orientation, of the stylet  906 . 
     Further, the interconnect  905  may also include an optical fiber  135  having core fibers  137  that propagate incident light and reflected light signals. The core fibers  137  of the interconnect  905  may also include Bragg fiber gratings  802 , which also cause reflected light signals  150  to be returned to the console  110 . The stylet  906  may include an optical connector  902  at its proximal end that is configured to optically couple with an optical connector  904  located at a distal end of the interconnect  905 . Additionally, a proximal end of the interconnect includes an optical connector  910  that is configured to optically couple with the connector  146  of the interconnect  145 . Thus, incident light  150  may propagate from the console  110  to the distal end of the stylet  906  and reflected light signals may propagate in the opposite direction to be received by the console  110 . 
     In particular, in the embodiment illustrated, the interconnect  905  is coupled (or otherwise secured) to the probe  812  via the securement mechanism  814 . The interconnect  905  is coupled to the probe  812  in such a manner so as to create a bend or kink (referred to herein as “bend  908 ”) in the interconnect  905 . The bend  908  causes a consistent strain on the gratings strain on the gratings of a particular section of core fibers  137  of the interconnect  905  and thus provides a consistent wavelength shift of the reflected light. As a result, the shape sensing logic  194  may receive reflected light and detect the positioning along the optical fiber  135  at which point the bend  908  occurs. The shape sensing logic  194  then utilizes the position of the bend  908  as a reference point in determining a positioning, location and/or orientation of the stylet  906 , and also that of a needle  901  configured to receive the stylet  906 . 
     Thus, medical instrument monitoring system  900  may obtain ultrasound image data of the imaging area  816  from the probe  812  and additionally determine needle tracking information based on the reflected light. The bend  908  serves as a reference point in determining a positioning of the stylet  906  (and of the needle  901 ) relative to the probe  812 . The needle tracking information may then be displayed as an overlay to the ultrasound image data as displayed on display  170  of the console  110 . 
     Referring now to  FIG. 9B , second exemplary embodiment of the medical instrument monitoring system of  FIG. 9A  during operation is shown in accordance with some embodiments. The embodiment of  FIG. 9B  illustrates that the interconnect  145  may include a predetermined bend  912  at its distal end. Further, the interconnect  145  may be coupled (or otherwise secured) to the probe  812  via the securement mechanism  814 , as discussed above. 
     Referring to  FIG. 10 , an illustration of the medical instrument monitoring system of  FIG. 8A  including a sterile drape during operation is shown in accordance with some embodiments.  FIG. 10  illustrates the medical instrument monitoring system  800  in operation where the imaging area  816  is within a sterile area  1002  that is located within the opening of the sterile drape  1000 . 
     Referring now to  FIG. 11 , an illustration of the medical instrument monitoring system of  FIG. 8A  during use including an exemplary visualization rendered on a display is shown in accordance with some embodiments.  FIG. 11  illustrates the medical instrument monitoring system  800  in operation and specifically illustrates the rendering of an ultrasound image  1100  and an image of the needle  801  as an overlay. The ultrasound image  1100  may include depth markers  1102 , an image depth scale  1104  and an image of a target vessel  1106 . 
     The shape sensing logic  194  generates the overlay  1108  by processing the reflected received from the from the gratings  802  of the needle  801  and gratings disposed along the length of the optical fiber  806  and specifically along the one or more core fibers  807 . Specifically, the physical state of the needle  801  and interconnect  805  are ascertained based on analytics of the wavelength shifts of the reflected light. Additionally, as the bend  820  causes a known wavelength shift of the light reflected from the corresponding portion of the interconnect  805 , the positioning and orientation of the needle  801  are determined relative to the bend  820 . Thus, the location of the distal tip of the needle  801  may be ascertained relative to the imaging area  816 . As a result, the shape sensing logic  194  may generate the overlay  1108 , e.g., an image of the needle  801  with its position and orientation relative to the ultrasound image  1100 . 
     Referring to  FIG. 12 , a flowchart of an exemplary methodology of inserting a medical instrument into a patient vasculature is shown in accordance with some embodiments. Each block illustrated in  FIG. 12  represents an operation performed in the method  1200 , which is initiated when the medical instrument monitoring system of any of  FIGS. 8A-11  are deployed to insert a medical instrument into a patient vasculature. Thus, the medical instrument may be either of the optically-enabled needle of  FIG. 8A  or the catheter assembly of  FIG. 9A . According to one embodiment, the method  1200  includes obtaining ultrasound images from an ultrasound probe and generating an ultrasound display illustrating one or more ultrasound images (blocks  1202 - 1204 ). Additionally, and occurring either prior to, following, or concurrently (at least partially overlapping in time) and either serially or in parallel, the method  1200  includes receiving reflect light signals from an optically-enabled medical instrument and processing the reflected light signals to determine a positioning and orientation of a distal tip of the medical instrument based on a known bend within an optical fiber cable coupled to the medical instrument (blocks  1206 - 1028 ). 
     Upon receiving the ultrasound images and the reflected light signals, and processing each accordingly, the method  1200  includes generating a second display illustrating the medical instrument as an overlay to the ultrasound display  1210  (block  1210 ). A shape sensing logic of the console that received the ultrasound images and the reflected light signals may perform processing to determine a positioning and an orientation of the medical instrument relative to the known bend of the optical fiber cable. In particular, the positioning and orientation of a distal tip of the medical instrument may be determined such that the distal tip may be included within the overlay, when applicable, in order to provide the clinician inserting the medical instrument within a patient a visual indication as to the positioning of the distal tip relative to a target vessel. Following generation of the second display illustrating the medical instrument as an overlay to the ultrasound display, the method  1200  includes rendering, or causing the rendering, of the second display on a display screen (block  1212 ). 
     While some particular embodiments have been disclosed herein, and while the particular embodiments have been disclosed in some detail, it is not the intention for the particular embodiments to limit the scope of the concepts provided herein. Additional adaptations and/or modifications can appear to those of ordinary skill in the art, and, in broader aspects, these adaptations and/or modifications are encompassed as well. Accordingly, departures may be made from the particular embodiments disclosed herein without departing from the scope of the concepts provided herein.