Patent Publication Number: US-2020289085-A1

Title: Flexible tip for intraluminal imaging device and associated devices, systems, and methods

Description:
RELATED APPLICATION 
     This application claims the benefit of and priority to U.S. Provisional Application No. 62/595,744, filed Dec. 7, 2017, which is incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to intraluminal ultrasound imaging and, in particular, to the structure of an intraluminal imaging device. For example, the intraluminal imaging device can include a flexible tip at the distal end of a flexible elongate member. 
     BACKGROUND 
     Intravascular ultrasound (IVUS) imaging is widely used in interventional cardiology as a diagnostic tool for assessing a diseased vessel, such as an artery, within the human body to determine the need for treatment, to guide the intervention, and/or to assess its effectiveness. An IVUS device including one or more ultrasound transducers is passed into the vessel and guided to the area to be imaged. The transducers emit ultrasonic energy in order to create an image of the vessel of interest. Ultrasonic waves are partially reflected by discontinuities arising from tissue structures (such as the various layers of the vessel wall), red blood cells, and other features of interest. Echoes from the reflected waves are received by the transducer and passed along to an IVUS imaging system. The imaging system processes the received ultrasound echoes to produce a cross-sectional image of the vessel where the device is placed. 
     Solid-state (also known as synthetic-aperture) IVUS catheters are one of the two types of IVUS devices commonly used today, the other type being the rotational IVUS catheter. Solid-state IVUS catheters carry a scanner assembly that includes an array of ultrasound transducers distributed around its circumference along with one or more integrated circuit controller chips mounted adjacent to the transducer array. The controllers select individual transducer elements (or groups of elements) for transmitting an ultrasound pulse and for receiving the ultrasound echo signal. By stepping through a sequence of transmit-receive pairs, the solid-state IVUS system can synthesize the effect of a mechanically scanned ultrasound transducer but without moving parts (hence the solid-state designation). Since there is no rotating mechanical element, the transducer array can be placed in direct contact with the blood and vessel tissue with minimal risk of vessel trauma. Furthermore, because there is no rotating element, the electrical interface is simplified. The solid-state scanner can be wired directly to the imaging system with a simple electrical cable and a standard detachable electrical connector, rather than the complex rotating electrical interface required for a rotational IVUS device. 
     Manufacturing an intravascular imaging device that can efficiently traverse physiology within the human body is challenging. In that regard, components at the distal portion of the imaging device can be assembled in a manner that excessively enlarges an outer diameter, which makes navigation through smaller diameter vessels difficult. Ensuring robust mechanical coupling between components can also be challenging. 
     SUMMARY 
     Intraluminal imaging devices are inserted into the human body to obtain information regarding the condition of various anatomies therein. For example, the intraluminal imaging device, such as an intravascular ultrasound (IVUS) device, can be introduced into to the body through a blood vessel and then guided to an anatomical area of interest. It is common for the intraluminal imaging device to encounter various obstructions while traveling within the body. In response to this, a front end of the intraluminal imaging device has been equipped with a tip member to facilitate the navigation of the intraluminal imaging device through the body. An outer profile of the tip member may be conical in shape and decrease in diameter from a leading front end of the tip member to a back end. The front end of the tip member may be formed using a material that is more flexible than the material used to form the back end of the tip. The tip member may be connected to the intraluminal imaging device by the application of an adhesive around the outer profile of each. To minimize impact the adhesive has on the outer profile of the tip member and the intraluminal imaging device, a cavity is formed in the proximal end of the tip member to receive the adhesive. The cavity functions to provide both a connection and a seal between the intraluminal imaging device and the tip member. The profile and flexible nature of the tip member assist the intraluminal imaging device in navigating obstructions while being guided through the body. Embodiments described herein advantageously minimize the outer diameter of the imaging assembly while achieving strong and efficient assembly and operation. 
     In an exemplary aspect, an intraluminal imaging device is provided. The device includes a flexible elongate member configured to be inserted into a lumen of a patient, the flexible elongate member comprising a proximal portion and a distal portion; an ultrasound imaging assembly disposed at the distal portion and configured to obtain ultrasound imaging data while positioned within the lumen of the patient; and a tip member disposed at the distal portion of the flexible elongate member, the tip member comprising a cavity adjacent to the ultrasound imaging assembly and configured to be filled with an adhesive to couple the tip member and the ultrasound imaging assembly. 
     In some aspects, the cavity comprises a junction region at a proximal portion of the tip member, and the cavity comprises a smaller outer diameter relative to the proximal portion of the tip member. In some aspects, the cavity comprises a linear outer diameter. In some aspects, the cavity further comprises a sloped outer diameter. In some aspects, a distal portion of the tip member comprises a crossing region configured to cross an occlusion of the lumen, wherein an outer diameter of the crossing region decreases along a longitudinal axis of the flexible elongate member. In some aspects, the crossing region of the tip member comprises a linear outer diameter. In some aspects, the crossing region of the tip member comprises a curvilinear outer diameter. In some aspects, a distal end of the tip member is shaped to facilitate crossing the occlusion. In some aspects, the distal end of the tip member comprises a linear outer diameter. In some aspects, the distal end of the tip member comprises a curvilinear outer diameter. In some aspects, the distal end of the tip member comprises a reinforcing apparatus. In some aspects, the reinforcing apparatus comprises a first color and the tip member comprises a second color different than the first color. In some aspects, the proximal portion of the tip member comprises a first material and the distal portion of the tip member comprises a second material. In some aspects, the tip member comprises an inner diameter associated with a lumen extending therethrough, wherein the inner diameter comprises an engagement feature configured to contact at least portion of the ultrasound imaging assembly disposed within the lumen. 
     In an exemplary aspect, an intraluminal imaging device is provided. The device includes a flexible elongate member configured to be inserted into a lumen of a patient, the flexible elongate member comprising a proximal portion and a distal portion; an ultrasound imaging assembly disposed at the distal portion and configured to obtain ultrasound imaging data while positioned within the lumen of the patient; and a tip member at the distal portion of the flexible elongate member and comprising a first material at a distal portion of the tip member and a second material at a proximal portion of the tip member. 
     In some aspects, the first material is less rigid than the second material such that the distal portion of the tip member is more flexible than the proximal portion of the tip member. In some aspects, the device further includes a transition region between the proximal portion and the distal portion, the transition region comprised of the first material and the second material. 
     In an exemplary aspect, an intraluminal imaging device is provided. The device includes a flexible elongate member configured to be inserted into a lumen of a patient, the flexible elongate member comprising a proximal portion and a distal portion; an ultrasound imaging assembly disposed at the distal portion and configured to obtain ultrasound imaging data while positioned within the lumen of the patient; and a tip member at the distal portion of the flexible elongate member and comprising a proximal portion and a distal portion, wherein the proximal portion of the tip member comprises linear outer diameter and varying wall thickness, and the distal portion of the tip member comprises a varying outer diameter and a constant wall thickness. 
     In some aspects, the wall thickness of the proximal portion of the tip member in is greater than the wall thickness of the distal portion of the tip member. 
     Additional aspects, features, and advantages of the present disclosure will become apparent from the following detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments of the present disclosure will be described with reference to the accompanying drawings, of which: 
         FIG. 1  is a diagrammatic schematic view of an imaging system, according to aspects of the present disclosure. 
         FIG. 2  is a diagrammatic top view of a scanner assembly in a flat configuration, according to aspects of the present disclosure. 
         FIG. 3  is a diagrammatic side view of a scanner assembly in a rolled configuration around a support member, according to aspects of the present disclosure. 
         FIG. 4  is a diagrammatic cross sectional side view of a distal portion of an intravascular device, according to aspects of the present disclosure. 
         FIG. 5 a    is a diagrammatic cross sectional side view of a tip member joint of an intraluminal device, according to aspects of the present disclosure. 
         FIG. 5 b    is a diagrammatic cross sectional side view of a tip member joint of an intraluminal device, according to aspects of the present disclosure. 
         FIG. 5 c    is a diagrammatic cross sectional side view of a tip member of an intraluminal device, according to aspects of the present disclosure. 
         FIG. 6 a    is a perspective view illustration of a tip member of an intraluminal device, according to aspects of the present disclosure. 
         FIG. 6 b    is a diagrammatic cross sectional side view of a tip member and imaging assembly, according to aspects of the present disclosure. 
         FIG. 7  is a diagrammatic cross sectional side view of a tip member of an intraluminal device, according to aspects of the present disclosure. 
         FIG. 8  is a diagrammatic cross sectional side view of a tip member of an intraluminal device, according to aspects of the present disclosure. 
         FIG. 9  is a side illustration of a tip member with a ramp type crossing profile, according to aspects of the present disclosure. 
         FIG. 10  is a side view illustration of a tip member with a slope type crossing profile, according to aspects of the present disclosure. 
         FIG. 11  is a side view illustration of a tip member with a step type crossing profile, according to aspects of the present disclosure. 
         FIG. 12  is a diagrammatic cross sectional side view illustration of a tip member with a bevel distal end, according to aspects of the present disclosure. 
         FIG. 13  is a diagrammatic cross sectional side view illustration of a tip member with a radial distal end, according to aspects of the present disclosure. 
         FIG. 14  is a diagrammatic cross sectional side view illustration of a tip member with a reinforced radial distal end, according to aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It is nevertheless understood that no limitation to the scope of the disclosure is intended. Any alterations and further modifications to the described devices, systems, and methods, and any further application of the principles of the present disclosure are fully contemplated and included within the present disclosure as would normally occur to one skilled in the art to which the disclosure relates. For example, while the focusing system is described in terms of cardiovascular imaging, it is understood that it is not intended to be limited to this application. The system is equally well suited to any application requiring imaging within a confined cavity. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one embodiment may be combined with the features, components, and/or steps described with respect to other embodiments of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately. 
       FIG. 1  is a diagrammatic schematic view of an intraluminal imaging system  100 , according to aspects of the present disclosure. For example, the system  100  can be an intraluminal ultrasound imaging system or intravascular ultrasound (IVUS) imaging system. The imaging system  100  may include an intraluminal ultrasound imaging device  102  such as a catheter, guide wire, or guide catheter, a patient interface module (PIM)  104 , a processing system or console  106 , and a monitor  108 . 
     At a high level, the IVUS device  102  emits ultrasonic energy from a transducer array  124  included in scanner assembly  110  mounted near a distal end of the catheter device. The ultrasonic energy is reflected by tissue structures in the medium, such as a vessel  120 , surrounding the scanner assembly  110 , and the ultrasound echo signals are received by the transducer array  124 . The PIM  104  transfers the received echo signals to the console or computer  106  where the ultrasound image (including the flow information) is reconstructed and displayed on the monitor  108 . The console or computer  106  can include a processor and a memory. The computer or computing device  106  can be operable to facilitate the features of the imaging system  100  described herein. For example, the processor can execute computer readable instructions stored on the non-transitory tangible computer readable medium. 
     The PIM  104  facilitates communication of signals between the console  106  and the scanner assembly  110  included in the IVUS device  102 . This communication includes the steps of: (1) providing commands to integrated circuit controller chip(s)  206 A,  206 B, illustrated in  FIG. 2 , included in the scanner assembly  110  to select the particular transducer array element(s) to be used for transmit and receive, (2) providing the transmit trigger signals to the integrated circuit controller chip(s)  206 A,  206 B included in the scanner assembly  110  to activate the transmitter circuitry to generate an electrical pulse to excite the selected transducer array element(s), and/or (3) accepting amplified echo signals received from the selected transducer array element(s) via amplifiers included on the integrated circuit controller chip(s) 126  of the scanner assembly  110 . In some embodiments, the PIM  104  performs preliminary processing of the echo data prior to relaying the data to the console  106 . In examples of such embodiments, the PIM  104  performs amplification, filtering, and/or aggregating of the data. In an embodiment, the PIM  104  also supplies high- and low-voltage DC power to support operation of the device  102  including circuitry within the scanner assembly  110 . 
     The console  106  receives the echo data from the scanner assembly  110  by way of the PIM  104  and processes the data to reconstruct an image of the tissue structures in the medium surrounding the scanner assembly  110 . For the example, the device  102  can be sized and shaped, structurally arranged, and/or otherwise configured to be positioned with a body lumen  120  of the patient. For example, the body lumen  120  can be a vessel in some embodiments. The console  106  outputs image data such that an image of the body lumen  120 , such as a cross-sectional image of the vessel  120 , is displayed on the monitor  108 . Lumen  120  may represent fluid filled or surrounded structures, both natural and man-made. The lumen  120  may be within a body of a patient. The lumen  120  may be a blood vessel, such as an artery or a vein of a patient&#39;s vascular system, including cardiac vasculature, peripheral vasculature, neural vasculature, renal vasculature, and/or or any other suitable lumen inside the body. For example, the device  102  may be used to examine any number of anatomical locations and tissue types, including without limitation, organs including the liver, heart, kidneys, gall bladder, pancreas, lungs; ducts; intestines; nervous system structures including the brain, dural sac, spinal cord and peripheral nerves; the urinary tract; as well as valves within the blood, chambers or other parts of the heart, and/or other systems of the body. In addition to natural structures, the device  102  may be may be used to examine man-made structures such as, but without limitation, heart valves, stents, shunts, filters and other devices. 
     In various embodiments, the intraluminal imaging device  102  and/or the imaging assembly  110  can obtain imaging data associated with intravascular ultrasound (IVUS) imaging, forward looking intravascular ultrasound (FL-IVUS) imaging, intravascular photoacoustic (IVPA) imaging, intracardiac echocardiography (ICE), forward-looking ICE (FLICE), transesophageal echocardiography (TEE), optical coherence tomography (OCT), and/or other suitable imaging modalities. The system  100  and/or the device  102  may also be configured to obtain physiologic data associated with pressure, flow, temperature, a fractional flow reserve (FFR) determination, a functional measurement determination, a coronary flow reserve (CFR) determination, radiographic imaging, angiographic imaging, fluoroscopic imaging, computed tomography (CT), magnetic resonance imaging (MRI), intravascular palpography, and/or other types of physiologic data. 
     In some embodiments, the IVUS device includes some features similar to traditional solid-state IVUS catheters, such as the EagleEye® catheter available from Volcano Corporation and those disclosed in U.S. Pat. No. 7,846,101 hereby incorporated by reference in its entirety. For example, the IVUS device  102  includes the scanner assembly  110  near a distal end of the device  102  and a transmission line bundle  112  extending along the longitudinal body of the device  102 . The transmission line bundle or cable  112  can include a plurality of conductors, including one, two, three, four, five, six, seven, or more conductors  218  ( FIG. 2 ). It is understood that any suitable gauge wire can be used for the conductors  218 . In an embodiment, the cable  112  can include a four-conductor transmission line arrangement with, e.g., 41 AWG gauge wires. In an embodiment, the cable  112  can include a seven-conductor transmission line arrangement utilizing, e.g., 44 AWG gauge wires. In some embodiments, 43 AWG gauge wires can be used. 
     The transmission line bundle  112  terminates in a PIM connector  114  at a proximal end of the device  102 . The PIM connector  114  electrically couples the transmission line bundle  112  to the PIM  104  and physically couples the IVUS device  102  to the PIM  104 . In an embodiment, the IVUS device  102  further includes a guide wire exit port  116 . Accordingly, in some instances the IVUS device is a rapid-exchange catheter. The guide wire exit port  116  allows a guide wire  118  to be inserted towards the distal end in order to direct the device  102  through the vessel  120 . 
       FIG. 2  is a top view of a portion of an ultrasound scanner assembly  110  according to an embodiment of the present disclosure. The assembly  110  includes a transducer array  124  formed in a transducer region  204  and transducer control logic dies  206  (including dies  206 A and  206 B) formed in a control region  208 , with a transition region  210  disposed therebetween. The transducer control logic dies  206  and the transducers  212  are mounted on a flex circuit  214  that is shown in a flat configuration in  FIG. 2 .  FIG. 3  illustrates a rolled configuration of the flex circuit  214 . The transducer array  202  is a non-limiting example of a medical sensor element and/or a medical sensor element array. The transducer control logic dies  206  is a non-limiting example of a control circuit. The transducer region  204  is disposed adjacent a distal portion  221  of the flex circuit  214 . The control region  208  is disposed adjacent the proximal portion  222  of the flex circuit  214 . The transition region  210  is disposed between the control region  208  and the transducer region  204 . Dimensions of the transducer region  204 , the control region  208 , and the transition region  210  (e.g., lengths  225 ,  227 ,  229 ) can vary in different embodiments. In some embodiments, the lengths  225 ,  227 ,  229  can be substantially similar or a length  227  of the transition region  210  can be greater than lengths  225 ,  229  of the transducer region and controller region, respectively. While the imaging assembly  110  is described as including a flex circuit, it is understood that the transducers and/or controllers may be arranged to form the imaging assembly  110  in other configurations, including those omitting a flex circuit. 
     The transducer array  124  may include any number and type of ultrasound transducers  212 , although for clarity only a limited number of ultrasound transducers are illustrated in  FIG. 2 . In an embodiment, the transducer array  124  includes 64 individual ultrasound transducers  212 . In a further embodiment, the transducer array  124  includes 32 ultrasound transducers  212 . Other numbers are both contemplated and provided for. With respect to the types of transducers, in an embodiment, the ultrasound transducers  124  are piezoelectric micromachined ultrasound transducers (PMUTs) fabricated on a microelectromechanical system (MEMS) substrate using a polymer piezoelectric material, for example as disclosed in U.S. Pat. No. 6,641,540, which is hereby incorporated by reference in its entirety. In alternate embodiments, the transducer array includes piezoelectric zirconate transducers (PZT) transducers such as bulk PZT transducers, capacitive micromachined ultrasound transducers (cMUTs), single crystal piezoelectric materials, other suitable ultrasound transmitters and receivers, and/or combinations thereof. 
     The scanner assembly  110  may include various transducer control logic, which in the illustrated embodiment is divided into discrete control logic dies  206 . In various examples, the control logic of the scanner assembly  110  performs: decoding control signals sent by the PIM  104  across the cable  112 , driving one or more transducers  212  to emit an ultrasonic signal, selecting one or more transducers  212  to receive a reflected echo of the ultrasonic signal, amplifying a signal representing the received echo, and/or transmitting the signal to the PIM across the cable  112 . In the illustrated embodiment, a scanner assembly  110  having 64 ultrasound transducers  212  divides the control logic across nine control logic dies  206 , of which five are shown in  FIG. 2 . Designs incorporating other numbers of control logic dies  206  including 8, 9, 16, 17 and more are utilized in other embodiments. In general, the control logic dies  206  are characterized by the number of transducers they are capable of driving, and exemplary control logic dies  206  drive 4, 8, and/or 16 transducers. 
     The control logic dies are not necessarily homogenous. In some embodiments, a single controller is designated a master control logic die  206 A and contains the communication interface for the cable  112 . Accordingly, the master control circuit may include control logic that decodes control signals received over the cable  112 , transmits control responses over the cable  112 , amplifies echo signals, and/or transmits the echo signals over the cable  112 . The remaining controllers are slave controllers  206 B. The slave controllers  206 B may include control logic that drives a transducer  212  to emit an ultrasonic signal and selects a transducer  212  to receive an echo. In the depicted embodiment, the master controller  206 A does not directly control any transducers  212 . In other embodiments, the master controller  206 A drives the same number of transducers  212  as the slave controllers  206 B or drives a reduced set of transducers  212  as compared to the slave controllers  206 B. In an exemplary embodiment, a single master controller  206 A and eight slave controllers  206 B are provided with eight transducers assigned to each slave controller  206 B. 
     The flex circuit  214 , on which the transducer control logic dies  206  and the transducers  212  are mounted, provides structural support and interconnects for electrical coupling. The flex circuit  214  may be constructed to include a film layer of a flexible polyimide material such as KAPTON™ (trademark of DuPont). Other suitable materials include polyester films, polyimide films, polyethylene napthalate films, or polyetherimide films, other flexible printed semiconductor substrates as well as products such as Upilex® (registered trademark of Ube Industries) and TEFLON® (registered trademark of E.I. du Pont). In the flat configuration illustrated in  FIG. 2 , the flex circuit  214  has a generally rectangular shape. As shown and described herein, the flex circuit  214  is configured to be wrapped around a support member  230  ( FIG. 3 ) to form a cylindrical toroid in some instances. Therefore, the thickness of the film layer of the flex circuit  214  is generally related to the degree of curvature in the final assembled scanner assembly  110 . In some embodiments, the film layer is between 5 μm and 100 μm, with some particular embodiments being between 12.7 μm and 25.1 μm. 
     To electrically interconnect the control logic dies  206  and the transducers  212 , in an embodiment, the flex circuit  214  further includes conductive traces  216  formed on the film layer that carry signals between the control logic dies  206  and the transducers  212 . In particular, the conductive traces  216  providing communication between the control logic dies  206  and the transducers  212  extend along the flex circuit  214  within the transition region  210 . In some instances, the conductive traces  216  can also facilitate electrical communication between the master controller  206 A and the slave controllers  206 B. The conductive traces  216  can also provide a set of conductive pads that contact the conductors  218  of cable  112  when the conductors  218  of the cable  112  are mechanically and electrically coupled to the flex circuit  214 . Suitable materials for the conductive traces  216  include copper, gold, aluminum, silver, tantalum, nickel, and tin, and may be deposited on the flex circuit  214  by processes such as sputtering, plating, and etching. In an embodiment, the flex circuit  214  includes a chromium adhesion layer. The width and thickness of the conductive traces  216  are selected to provide proper conductivity and resilience when the flex circuit  214  is rolled. In that regard, an exemplary range for the thickness of a conductive trace  216  and/or conductive pad is between 10-50 μm. For example, in an embodiment, 20 μm conductive traces  216  are separated by 20 μm of space. The width of a conductive trace  216  on the flex circuit  214  may be further determined by the width of the conductor  218  to be coupled to the trace/pad. 
     The flex circuit  214  can include a conductor interface  220  in some embodiments. The conductor interface  220  can be a location of the flex circuit  214  where the conductors  218  of the cable  114  are coupled to the flex circuit  214 . For example, the bare conductors of the cable  114  are electrically coupled to the flex circuit  214  at the conductor interface  220 . The conductor interface  220  can be tab extending from the main body of flex circuit  214 . In that regard, the main body of the flex circuit  214  can refer collectively to the transducer region  204 , controller region  208 , and the transition region  210 . In the illustrated embodiment, the conductor interface  220  extends from the proximal portion  222  of the flex circuit  214 . In other embodiments, the conductor interface  220  is positioned at other parts of the flex circuit  214 , such as the distal portion  220 , or the flex circuit  214  omits the conductor interface  220 . A value of a dimension of the tab or conductor interface  220 , such as a width  224 , can be less than the value of a dimension of the main body of the flex circuit  214 , such as a width  226 . In some embodiments, the substrate forming the conductor interface  220  is made of the same material(s) and/or is similarly flexible as the flex circuit  214 . In other embodiments, the conductor interface  220  is made of different materials and/or is comparatively more rigid than the flex circuit  214 . For example, the conductor interface  220  can be made of a plastic, thermoplastic, polymer, hard polymer, etc., including polyoxymethylene (e.g., DELRIN®), polyether ether ketone (PEEK), nylon, and/or other suitable materials. As described in greater detail herein, the support member  230 , the flex circuit  214 , the conductor interface  220  and/or the conductor(s)  218  can be variously configured to facilitate efficient manufacturing and operation of the scanner assembly  110 . 
     In some instances, the scanner assembly  110  is transitioned from a flat configuration ( FIG. 2 ) to a rolled or more cylindrical configuration ( FIGS. 3 and 4 ). For example, in some embodiments, techniques are utilized as disclosed in one or more of U.S. Pat. No. 6,776,763, titled “ULTRASONIC TRANSDUCER ARRAY AND METHOD OF MANUFACTURING THE SAME” and U.S. Pat. No. 7,226,417, titled “HIGH RESOLUTION INTRAVASCULAR ULTRASOUND TRANSDUCER ASSEMBLY HAVING A FLEXIBLE SUBSTRATE,” each of which is hereby incorporated by reference in its entirety. 
     As shown in  FIGS. 3 and 4 , the flex circuit  214  is positioned around the support member  230  in the rolled configuration.  FIG. 3  is a diagrammatic side view with the flex circuit  214  in the rolled configuration around the support member  230 , according to aspects of the present disclosure.  FIG. 4  is a diagrammatic cross-sectional side view of a distal portion of the intravascular device  110 , including the flex circuit  214  the support member  230  and a tip member  304 , according to aspects of the present disclosure. 
     The support member  230  can be referenced as a unibody in some instances. The support member  230  can be composed of a metallic material, such as stainless steel, or non-metallic material, such as a plastic or polymer as described in U.S. Provisional Application No. 61/985,220, “Pre-Doped Solid Substrate for Intravascular Devices,” filed Apr. 28, 2014, the entirety of which is hereby incorporated by reference herein. The support member  230  can be ferrule having a distal portion  262  and a proximal portion  264 . The support member  230  can define a lumen  236  extending longitudinally therethrough. The lumen  236  is in communication with the exit port  116  and is sized and shaped to receive the guide wire  118  ( FIG. 1 ). The support member  230  can be manufactured accordingly to any suitable process. For example, the support member  230  can be machined, such as by removing material from a blank to shape the support member  230 , or molded, such as by an injection molding process. In some embodiments, the support member  230  may be integrally formed as a unitary structure, while in other embodiments the support member  230  may be formed of different components, such as a ferrule and stands  242 ,  244 , that are fixedly coupled to one another. 
     Stands  242 ,  244  that extend vertically are provided at the distal and proximal portions  262 ,  264 , respectively, of the support member  230 . The stands  242 ,  244  elevate and support the distal and proximal portions of the flex circuit  214 . In that regard, portions of the flex circuit  214 , such as the transducer portion  204 , can be spaced from a central body portion of the support member  230  extending between the stands  242 ,  244 . The stands  242 ,  244  can have the same outer diameter or different outer diameters. For example, the distal stand  242  can have a larger or smaller outer diameter than the proximal stand  244 . To improve acoustic performance, any cavities between the flex circuit  214  and the surface of the support member  230  are filled with a backing material  246 . The liquid backing material  246  can be introduced between the flex circuit  214  and the support member  230  via passageways  235  in the stands  242 ,  244 . In some embodiments, suction can be applied via the passageways  235  of one of the stands  242 ,  244 , while the liquid backing material  246  is fed between the flex circuit  214  and the support member  230  via the passageways  235  of the other of the stands  242 ,  244 . The backing material can be cured to allow it to solidify and set. In various embodiments, the support member  230  includes more than two stands  242 ,  244 , only one of the stands  242 ,  244 , or neither of the stands. In that regard the support member  230  can have an increased diameter distal portion  262  and/or increased diameter proximal portion  264  that is sized and shaped to elevate and support the distal and/or proximal portions of the flex circuit  214 . 
     The support member  230  can be substantially cylindrical in some embodiments. Other shapes of the support member  230  are also contemplated including geometrical, non-geometrical, symmetrical, non-symmetrical, cross-sectional profiles. Different portions the support member  230  can be variously shaped in other embodiments. For example, the proximal portion  264  can have a larger outer diameter than the outer diameters of the distal portion  262  or a central portion extending between the distal and proximal portions  262 ,  264 . In some embodiments, an inner diameter of the support member  230  (e.g., the diameter of the lumen  236 ) can correspondingly increase or decrease as the outer diameter changes. In other embodiments, the inner diameter of the support member  230  remains the same despite variations in the outer diameter. 
     A proximal inner member  256  and a proximal outer member  254  are coupled to the proximal portion  264  of the support member  230 . The proximal inner member  256  and/or the proximal outer member  254  can be flexible elongate member that extend from proximal portion of the intravascular  102 , such as the proximal connector  114 , to the imaging assembly  110 . For example, the proximal inner member  256  can be received within a proximal flange  234 . The proximal outer member  254  abuts and is in contact with the flex circuit  214 . A tip member  304  is coupled to the distal portion  262  of the support member  230 . As discussed further herein, the tip member  304  can be a flexible component that defines a distal most portion of the intravascular device  102 . For example, the tip member  304  is positioned around the distal flange  232 . The tip member  304  can abut and be in contact with the flex circuit  214  and the stand  242 . The tip member  304  can be the distal-most component of the intravascular device  102 . The tip member  304  functions to facilitate the translation of the intraluminal device  300 , through any number of anatomies encountered in a patient, including but not limited to lesions and blood vessels with short radii. 
       FIGS. 5 a  and 5 b    illustrate an embodiment of an intraluminal device  300 , including a joint  302  which facilitates the connection of the imaging assembly  110 , which in certain embodiments is a scanner assembly, and the tip member  304 .  FIG. 5 a    is a side view illustration of the imaging assembly  110  and the tip member  304  joint  302 .  FIG. 5 b    is a cross-sectional side view illustration of the imaging assembly  110  and the tip member  304  joint  302 . For clarity, the proximal portion of the intraluminal device  300  is shown the left side of  FIGS. 5 a  and 5 b   , and more distal portions are shown on the right side. 
     The intraluminal device  300  can be similar to the intravascular device  102  in some aspects. With reference to  FIGS. 5 a  and 5 b   , the imaging assembly  110  and the tip member  304  joint  302  may include an adhesive  306  disposed at a junction region  308  positioned between a proximal portion  310  of the tip member  304  and the distal end  312  of the imaging assembly  110 . The adhesive  306  functions to mechanically connect the imaging assembly  110  and the tip member  304 . Further, the adhesive  306  functions to provide a hermetic seal between the tip member  304  and the distal end  312  of the imaging assembly  110 . As discussed further herein, the junction region  308  is configured to receive the adhesive  306  while limiting the overall diameter of the tip member  304  and the joint  302 . It is anticipated that one or more adhesives  306  may be disposed in the junction region  308 . The adhesive  306  may be disposed within the junction region  308  such that a limited amount of adhesive  306  overlaps the imaging assembly  110  and the proximal portion  310  of the tip member  304 .  FIG. 5 b    provides an illustration of the support member  230  and the inner member  256  extending through the junction region  308  and into the proximal portion  310  of the tip member  304 . 
     Turning now to  FIG. 5 c   , a cross-sectional view of the tip member  304  is presented. The tip member  304  may include a lumen  314  extending between the walls  316  of the tip member  304  along a longitudinal axis  318  between the junction region  308 , the proximal portion  310  and a distal portion  320 . It will be appreciated that the respective lengths and geometrical profiles of the junction region  308 , the proximal portion  310  and the distal portion  320  may vary in accordance with the functional objective of the tip member  304  as discussed further herein.  FIG. 5 c    depicts the walls  316  sloping in a linear fashion from the proximal portion  310  to the distal portion  320 . However as described further herein, the walls  316  may also slope in a curvilinear fashion. The walls  316  and the lumen  314  may define an inner diameter  322  of the tip member  304 . An engagement feature  324  may be positioned along the inner diameter  322  to secure the support member  230  within the proximal portion  310 . It is anticipated that the engagement feature  324  may include any number of securing mechanisms or methods as known in the art, such as, but not limited to surface roughening, grooves, threads to secure the support member  230  to the inner diameter  322  of the tip member  304 . 
     The tip member  304  may also include a crossing region  326 , which may be defined as the area of the tip member  304  containing the largest outer diameter of the tip member  304  profile and is generally located in the proximal portion  310  or the junction region  308 . 
     The junction region  308  is disposed between the proximal portion  310  of the tip member  304  and the imaging assembly  110  within the joint  302 . The junction region  308  includes a cavity  328  for receiving the adhesive  306  used to facilitate a mechanical connection between the imaging assembly  110  and the tip member  304 . The cavity  328  may be configured to receive the adhesive  306  for the mechanical connection, while at the same time functioning to minimize the crossing region  326  of the tip member  304 . It is anticipated however, that the addition of adhesive  306  to the junction region  308  may increase the overall diameter of the tip member  304  becoming the de facto location of the crossing region  326 . This may particularly be the case where it is desired to create an adhesive  306  overlap in the joint  302  between the imaging assembly  110  and the tip member  304  as previously discussed. As shown in  FIG. 5 c   , the cavity  328  of the junction region  308  may be defined by a linear slope of the wall  316  that extends away from the proximal portion  310  towards the imaging assembly  110 , which forms an annular triangular cross section. However, as discussed further herein the cavity  328  may be defined by any number of geometries which facilitate minimizing the crossing region  326  of the tip member  304 . 
     With continued reference to  FIG. 5 c   , the wall  316  is also shown linearly sloping away from the proximal portion  310  of the tip member  304  towards the distal portion  320  of the tip member. In this configuration, the outer diameter  330  of the tip member  304  gradually decreases along the longitudinal axis  318  from the proximal portion  310  to the distal portion  320 . At the most distal position of the distal portion  320  is the distal end  332 , which as discussed further herein, is the first point of contact between the tip member  304  of the intraluminal device  300  and any obstruction along the path of the intraluminal device  300 . 
       FIGS. 6 a  and 6 b    illustrate an enlarged perspective and diagrammatic cross sectional view of the imaging assembly  110  and the tip member  304  joint  302 , respectively.  FIG. 6 a    illustrates the support member  230  of the imaging assembly  110  extending through the junction region  308  of the tip member  304  to the proximal portion  310 . The cavity  328  is shown an in annular configuration with a trapezoidal cross-section. In contrast to the linear slopes depicted in  FIGS. 5 a   - 5   c,  in  FIG. 6 a    the tip member  304  is shown with a partial curvilinear profile that decreases along the longitudinal axis  318  from the proximal portion  310  to the distal portion  320 . The distal end  332  of the distal portion  320  contains a reinforcing apparatus  334 , which in certain embodiments is a reinforcement ring, positioned between the inner diameter  322  and the lumen  314  of the tip member  304 . As discussed further herein, the reinforcement apparatus  334  functions to provide rigidity to the distal portion  320  tip member  304 . This rigidity will prevent the deformation of the tip member  304  upon encountering a relatively rigid obstruction along the along the path of the intraluminal device  300 . 
       FIG. 6 b    depicts a configuration of the tip member  304  with a linear profile that decreases along the longitudinal axis  318  from the proximal portion  310  to the distal portion  320  similar as to illustrated in  FIGS. 5 a   - 5   c.  This configuration however, illustrates an annular cavity  328  containing adhesive  306 , which has a rectangular cross section in contrast with the triangular and trapezoidal cross sections previously described. It will be appreciated that tip member  304  may be comprised of any number of combinations of geometrical shaped profiles and cavity  328  cross sections. 
       FIG. 7  presents a cross sectional side view of the tip member  304  in which the tip member  304  is made using an injection molding process. This process may be implemented to control the flexibility of the tip member  304 . The process includes molding the distal portion  320  using a flexible first material  336  and molding the proximal portion  310  using a second material  338 , which is less flexible than the first material  336 . This configuration provides a more flexible distal portion  320  of the tip member  304 , which is useful for navigating obstructions encountered along the path of the intraluminal device  300 . Additionally, this configuration provides an optimized transition to a less flexible proximal portion  310  of the tip member  304 , which is connected to the rigid imaging assembly  110 . The first material  336  may be selected from any number of materials with flexible properties including, but not limited to, plastic, polymer, elastomer, polyether block amide, Pebax® (e.g., Pebax® 5533), and/or other suitable materials. Further, the second material  338  may be selected from any number of materials that are less flexible than selected first material  336 . The process may be configured to control the quantity of the first material  336  and second material  338  injected into the distal portion  320  and the proximal portion  310  respectively ultimately determining the flexibility of the tip member  304 . For example, although  FIG. 7  shows a greater quantity of the first material  336  in the tip member  304 , depending on the desired magnitude of rigidity of the tip member  304  the injection molding process may be modified to increase the quantity of the second material  338  in the proximal portion  310 . 
     The tip member  304  in  FIG. 7  contains features that are similar to the tip member  304  presented in  FIG. 5 c   , but also includes a transition region  340  formed from both the first material  336  and the second material  338  and disposed between the proximal portion  310  and the distal portion  320 . The transition region  340  includes an interlocking assembly  342 , which functions to create a bond between the first material  336  and the second material  338 . The interlocking assembly  342  may employ any number of methods or apparatuses for securing the first material  336  and the second material  338  such as, but not limited to a ribbed or textured interface region. Although,  FIG. 7  describes two materials being used in the injection molding process to form the tip member  304 , it will be appreciated that molding process may employ any number of materials with differing magnitudes of flexibility. 
       FIG. 8  illustrates a cross sectional side view of the tip member  304  in which the proximal portion  310  has a constant diameter  330  while the wall  316  thickness of the tip member  304  varies along the longitudinal axis  318  and the distal portion  320  has a varying diameter  330  while wall  316  thickness of the tip member  304  is constant along the longitudinal axis  318 . Similar to the tip member  304  described with respect to  FIG. 7 , the tip member  304  presented in  FIG. 8  contains features that are similar to the tip member  304  presented in  FIG. 5 c    except for the geometry of the lumen  314 . It will be appreciated that shape of the lumen  314  may derive from any number of linear or non-linear geometries as desired. The tip member  304  presented in  FIG. 8 , illustrates an alternative approach to controlling the flexibility of the tip member  304  with the use of one material as opposed to multiple (e.g. a first material  336  and a second material  338  as discussed with reference to  FIG. 7 ). By increasing the wall  316  thickness along the proximal portion  310  and decreasing the wall  316  thickness along the distal portion  320  around the lumen  314 , the tip member  304  may be configured to contain flexibility at the distal portion  320  and less flexibility at the proximal portion  310 . 
       FIGS. 9, 10, and 11  present various types of tip member  304  crossing profiles containing different geometries, which may be situationally used to facilitate translation through or around difficult anatomies. In  FIG. 9 , a side view of a tip member  304  with a ramp type crossing profile is presented. The ramp type crossing profile has a small outer diameter  330  at the distal portion  320 , which gradually increases on a linear slope with respect to the longitudinal axis  318  until reaching the proximal portion  310 . The proximal portion  310  may include a profile segment with slope of zero. The use of a tip member  304  with a ramp type crossing profile is advantageous in situations where such as traversing a tight bend within vasculature or other body lumen, where a thin and flexible leading edge consistently transitions to a thicker, less flexible proximal edge. In  FIG. 10 , a side view of the tip member  304  with a slope type crossing profile is presented. Similar to the ramp type crossing profile, the slope type crossing profile also has a smaller outer diameter  330  at the distal portion  320 , which gradually increases along the longitudinal axis  318  towards the proximal portion  310 . However, in lieu of increasing linearly, the outer diameter  330  increases along a curvilinear slope from the distal portion  320  to the proximal portion  310 . The use of a tip member  304  with a slope type crossing profile is advantageous in situations where such as crossing a partial or complete occlusion within vasculature or other body lumen where the tip ramp would act as a wedge. In  FIG. 11 , a side view of the tip member  304  with step type crossing profile is presented. Similar to the ramp and slope type crossing profiles of  FIGS. 9 and 10 , the step type crossing profile has a smaller diameter  330  in the distal portion  320  than in the proximal portion  310 . However, in the step type crossing profile, the smaller diameter  330  is maintained throughout the distal portion  320  on a slope of zero until encountering the proximal portion  310  where it increases along a curvilinear slope to a larger diameter  330 . The use of a tip member  304  with a step type crossing profile is advantageous in situations where such as crossing a stent within vasculature or other body lumen where a flexible distal portion is desirable to avoid pushing the guide wire and leading edge of the tip against the stent struts. It will be appreciated that the lengths of each distal portion  320  and proximal portion  310  of the profiles in each tip member  304  as well as their respective slopes and radii may be optimized for general use or for specific clinical scenarios. 
       FIGS. 12, 13, and 14  present various types of distal ends  332  of the tip member  304 , with profiles containing different geometries, which may be situationally used to prevent deformation of the tip member  304  upon encountering an obstruction. The tip member  304  may be given a first color and the distal end  332  may be given a second color to assist in the guide wire  118  loading process. As previously discussed, the distal end  332 , is disposed at the most distal position of the distal portion  320 . In  FIG. 12  a cross sectional side view of a tip member  304  with a bevel distal end is presented. The distal end  320  contains an outer diameter  344  that linearly slopes away from the wall  316  of the tip member  304  towards an edge  346  of distal end  332 . The use of a tip member  304  with a bevel distal end  332  is advantageous in situations where the device is traversing geometry within vasculature or other body lumen that could catch on the tip (e.g. an occlusion or stent). In  FIG. 13  a cross sectional the side view of a tip member  304  with a radial distal end  332  is presented. The distal end  332  contains an outer diameter  348  that slopes away from the wall  316  of the tip member  304  in a curvilinear manner towards the edge  346  of the distal end  332 . The use of a tip member  304  with a radial distal end  332  is advantageous in situations where the device is traversing a bend within vasculature or other body lumen (especially while on a stiff segment of guide wire) where additional material thickness is needed to prevent tip material deformation. In  FIG. 14 , a cross sectional side view of the tip member  304  with a reinforcing apparatus  334  is presented. The reinforcing apparatus  334  may be disposed about an outer diameter  350  of the lumen at the edge  346  of the distal end  332 . The reinforcing apparatus  334  may also be given a second color to distinguish it from the tip member  304 . It will be appreciated that the reinforcing apparatus  334  may be used with any distal end  332  geometrical profile.