Patent Description:
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 acoustic 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.

When designing an IVUS device it is important to take into consideration practical limitations such as manufacturability, reliability, resiliency and mechanical performance. It is desirable that the ultrasound catheter assembly produce high quality raw image signals for the signal processing system located outside the body within which the intravascular ultrasound transducer assembly is inserted for imaging. However, there is an interest in limiting the number of parts since added complexity can increase the manufacturing costs and reduce the yield of the intravascular ultrasound catheter assemblies. It is desirable that the devices be sufficiently resilient and have sufficient structural support to navigate tortuous regions of the vasculature without damaging the electronic components of the IVUS device.

Conventional IVUS devices include a support member, which may also be referred to as a chassis, or a unibody, formed of a metal tube. An ultrasound imaging assembly is positioned over or around the support member. The support member provides structural support, rigidity, radiopacity and other characteristics to the scanner assembly. Conventional support members suffer from a number of drawbacks. For example, the manufacturing techniques available for metals (e.g., milling, welding, etc.) limit the geometric configuration of support members that can be produced. Similarly, steel cannot be re-flowed with polymers and does not effectively scatter or attenuate ultrasound waves. Accordingly, conventional support members constructions may limit mechanical and/or acoustic performance of IVUS devices.

<CIT> discloses an ultrasound catheter suitable for insertion in body lumens of a patient during medical procedures. An ultrasound transducer is provided at the distal tip of the catheter. An inflatable balloon is provided at the distal end of the catheter on the proximal side of the ultrasound transducer. The catheter has lumens for inflation fluid, electrical wires, and a guide wire. A sheath that runs through the balloon is used to isolate the electrical wires and guide wire from inflation fluid in the interior of the balloon. A structure being a hollow tube with a bore is used to form a distal portion of the guide wire lumen when the catheter is fully assembled. Separate retaining rings (e.g., ruby retaining rings that have been individually machined and attached to the surface of tube) are positioned along the tube to form annular transducer array gap.

<CIT> discloses an intraluminal imaging device comprising a flexible elongate member sized and shaped for insertion into a vessel of a patient and an imaging assembly, including a flex circuit, arranged at the distal portion of the flexible elongate member. The flex circuit is disposed in the rolled configuration around the support member. To improve acoustic performance, any cavities between the flex circuit and the surface of the support member are filled with a backing material.

The present application provides an improved intravascular imaging probe that includes a multiple material support member or chassis as part of the imaging assembly at the distal portion of the IVUS catheter. The support member is formed from multiple (i.e. two, three, or more) materials with various structural complexities. The chassis may include a cylindrical hollow core or a hypotube combined with polymer features over molded, fitted, or otherwise coupled directly to the hollow core. The multi material construction allows for features to be directly molded or coupled to the support structure, which may improve and/or simplify the manufacturing process, and may provide for more varied geometrical configurations that exhibit improved mechanical and/or acoustic performance. In some aspects, the multi-material chassis may have rigid structures to prevent any stresses imposed on the sensor components and more flexible structures to increase the resilience and maneuverability of the IVUS catheter.

According to an embodiment of the present disclosure, an intraluminal ultrasound imaging catheter includes: a flexible elongate member configured to be positioned within a body lumen of a patient; a support member coupled to a distal portion of the flexible elongate member. The support member includes: a hollow inner member comprising a first material; a first annular member positioned around a perimeter of the hollow inner member at a proximal portion of the hollow inner member, wherein the first annular member extends radially outward from the hollow inner member, and wherein the first annular member comprises a second material that is different from the first material. The intraluminal ultrasound imaging catheter further includes an ultrasound scanner assembly positioned around the first annular member of the support member, wherein the ultrasound scanner assembly is configured to obtain ultrasound imaging data of the body lumen.

In some embodiments, the hollow inner member comprises a cylindrical shape. In some embodiments, the hollow inner member comprises a uniform outer surface and a uniform inner surface. In some embodiments, the hollow inner member comprises an outer surface with a first recess, and the first recess is formed at the proximal portion of the hollow inner member such that the second material of the first annular member is positioned within the first recess. In some embodiments, the first material of the hollow inner member comprises a metal and the second material of the first annular member comprises a polymer. In some embodiments, the second material is over molded onto the hollow inner member. In some embodiments, the first annular member comprises a ring shape. In some embodiments, the first annular member comprises a polygonal shape. In some embodiments, the hollow inner member and the first annular member are coupled by an adhesive at the proximal portion of the hollow inner member. In some embodiments, the adhesive comprises a polymer material.

The support member further comprises a sleeve member positioned around the perimeter of the hollow inner member at an intermediate portion of the inner hollow member. The sleeve member is positioned distal of the first annular member. The sleeve member comprises a third material. In some embodiments, the hollow inner member comprises an outer surface with a second recess. In some embodiments, the second recess is formed at the intermediate portion of the hollow inner member such that the sleeve member is positioned within the second recess to form a continuous outer profile with the hollow inner member. In some embodiments, the third material of the sleeve member comprises a polymer. In some embodiments, the support member further comprises a second annular member positioned around the perimeter of the hollow inner member at a distal portion of the hollow inner member. In some embodiments, the second annular member extends radially outward from the hollow inner member. In some embodiments, the ultrasound scanner assembly is positioned around the second annular member.

In some embodiments, the second annular member comprises the second material, and the second annular member comprises a ring shape. In some embodiments, the support member further comprises a distal tubular member extending distally of the hollow inner member, and the second annular member and the distal tubular member comprise a flexible third material. In some embodiments, the first annular member, the sleeve member, and the second annular member form an integral component positioned around the perimeter of the hollow inner member. In some embodiments, a sidewall of the hollow inner member comprises at least one of a groove or a through-hole.

In some embodiments, the intraluminal ultrasound imaging catheter further includes: a proximal tubular member coupled to the proximal portion of the hollow inner member and extending proximally of the hollow inner member; and a distal tip member coupled to a distal portion end of the hollow inner member and extending distally of the hollow inner member, wherein the distal tip member comprises: an annular section positioned around the perimeter of the hollow inner member at a distal portion of the hollow inner member, wherein the annular section extends radially outward from the hollow inner member; and a tapered section extending distally of the annular section, wherein the proximal tubular member and the distal tip member comprise a polymer material.

According to another embodiment of the present disclosure, an intraluminal ultrasound imaging system includes: an intraluminal ultrasound imaging catheter, comprising: a flexible elongate member configured to be positioned within a body lumen of a patient; a support member coupled to a distal portion of the flexible elongate member, wherein the support member comprises: a metallic, hollow inner member comprising a first material; a polymeric ring positioned around a perimeter of the hollow inner member at a proximal portion of the hollow inner member, wherein the polymeric ring extends radially outward from the hollow inner member; and an ultrasound scanner assembly positioned around the polymeric ring of the support member, wherein the ultrasound scanner assembly is configured to obtain ultrasound imaging data of the body lumen; and a processor circuit in communication with the intraluminal ultrasound imaging catheter, wherein the processor circuit is configured to generate an intraluminal ultrasound image using the ultrasound imaging data and output the intraluminal ultrasound image to a display.

<FIG> is a diagrammatic schematic view of an ultrasound imaging system <NUM>, according to aspects of the present disclosure. The ultrasound imaging system <NUM> can be an intraluminal imaging system. In some instances, the system <NUM> can be an intravascular ultrasound (IVUS) imaging system. The system <NUM> may include an intraluminal imaging device <NUM> such as a catheter, guide wire, or guide catheter, a patient interface module (PIM) <NUM>, a processing system or console <NUM>, and a monitor <NUM>. The intraluminal imaging device <NUM> can be an ultrasound imaging device. In some instances, the device <NUM> can be IVUS imaging device, such as a solid-state IVUS device.

At a high level, the IVUS device <NUM> emits ultrasonic energy, or ultrasound signals, from a transducer array <NUM> included in scanner assembly <NUM> mounted near a distal end of the catheter device. The ultrasonic energy is reflected by tissue structures in the medium, such as a vessel <NUM>, or another body lumen surrounding the scanner assembly <NUM>, and the ultrasound echo signals are received by the transducer array <NUM>. In that regard, the device <NUM> can be sized, shaped, or otherwise configured to be positioned within the body lumen of a patient. The PIM <NUM> transfers the received echo signals to the console or computer <NUM> where the ultrasound image (including the flow information) is reconstructed and displayed on the monitor <NUM>. The console or computer <NUM> can include a processor and a memory. The computer or computing device <NUM> can be operable to facilitate the features of the IVUS imaging system <NUM> described herein. For example, the processor can execute computer readable instructions stored on the non-transitory tangible computer readable medium.

The PIM <NUM> facilitates communication of signals between the IVUS console <NUM> and the scanner assembly <NUM> included in the IVUS device <NUM>. This communication includes the steps of: (<NUM>) providing commands to integrated circuit controller chip(s) 206A, 206B, illustrated in <FIG>, included in the scanner assembly <NUM> to select the particular transducer array element(s), or acoustic element(s), to be used for transmit and receive, (<NUM>) providing the transmit trigger signals to the integrated circuit controller chip(s) 206A, 206B included in the scanner assembly <NUM> to activate the transmitter circuitry to generate an electrical pulse to excite the selected transducer array element(s), and/or (<NUM>) accepting amplified echo signals received from the selected transducer array element(s) via amplifiers included on the integrated circuit controller chip(s)<NUM> of the scanner assembly <NUM>. In some embodiments, the PIM <NUM> performs preliminary processing of the echo data prior to relaying the data to the console <NUM>. In examples of such embodiments, the PIM <NUM> performs amplification, filtering, and/or aggregating of the data. In an embodiment, the PIM <NUM> also supplies high- and low-voltage DC power to support operation of the device <NUM> including circuitry within the scanner assembly <NUM>.

The IVUS console <NUM> receives the echo data from the scanner assembly <NUM> by way of the PIM <NUM> and processes the data to reconstruct an image of the tissue structures in the medium surrounding the scanner assembly <NUM>. The console <NUM> outputs image data such that an image of the vessel <NUM>, such as a cross-sectional image of the vessel <NUM>, is displayed on the monitor <NUM>. Vessel <NUM> may represent fluid filled or surrounded structures, both natural and man-made. The vessel <NUM> may be within a body of a patient. The vessel <NUM> may be a blood vessel, as an artery or a vein of a patient'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 <NUM> 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 <NUM> may be used to examine man-made structures such as, but without limitation, heart valves, stents, shunts, filters and other devices.

In some embodiments, the IVUS device includes some features similar to traditional solid-state IVUS catheters, such as the EagleEye® catheter available from Koninklijke Philips N. and those disclosed in <CIT>. For example, the IVUS device <NUM> includes the scanner assembly <NUM> near a distal end of the device <NUM> and a transmission line bundle <NUM> extending along the longitudinal body of the device <NUM>. The transmission line bundle or cable <NUM> can include a plurality of conductors, including one, two, three, four, five, six, seven, or more conductors <NUM> (<FIG>). It is understood that any suitable gauge wire can be used for the conductors <NUM>. In an embodiment, the cable <NUM> can include a four-conductor transmission line arrangement with, e.g., <NUM> diameter (<NUM> American Wire Gauge, AWG) wires. In an embodiment, the cable <NUM> can include a seven-conductor transmission line arrangement utilizing, e.g., <NUM> diameter (<NUM> AWG) wires. In some embodiments, <NUM> diameter (<NUM> AWG) wires can be used.

The transmission line bundle <NUM> terminates in a PIM connector <NUM> at a proximal end of the device <NUM>. The PIM connector <NUM> electrically couples the transmission line bundle <NUM> to the PIM <NUM> and physically couples the IVUS device <NUM> to the PIM <NUM>. In an embodiment, the IVUS device <NUM> further includes a guide wire exit port <NUM>. Accordingly, in some instances the IVUS device is a rapid-exchange catheter. The guide wire exit port <NUM> allows a guide wire <NUM> to be inserted towards the distal end in order to direct the device <NUM> through the vessel <NUM>.

In an embodiment, the image processing system <NUM> generates flow data by processing the echo signals from the IVUS device <NUM> into Doppler power or velocity information. The image processing system <NUM> may also generate B-mode data by applying envelope detection and logarithmic compression on the conditioned echo signals. The processing system <NUM> can further generate images in various views, such as 2D and/or 3D views, based on the flow data or the B-mode data. The processing system <NUM> can also perform various analyses and/or assessments. For example, the processing system <NUM> can apply virtual histology (VH) techniques, for example, to analyze or assess plaques within a vessel (e.g., the vessel <NUM>). The images can be generated to display a reconstructed color-coded tissue map of plaque composition superimposed on a cross-sectional view of the vessel.

In an embodiment, the processing system <NUM> can apply a blood flow detection algorithm (e.g., ChromaFlo) to determine the movement of blood flow, for example, by acquiring image data of a target region (e.g., the vessel <NUM>) repeatedly and determining the movement of the blood flow from the image data. The blood flow detection algorithm operates based on the principle that signals measured from vascular tissue are relatively static from acquisition to acquisition, whereas signals measured from blood flow vary at a characteristic rate corresponding to the flow rate. As such, the blood flow detection algorithm may determine movements of blood flow based on variations in signals measured from the target region between repeated acquisitions. To acquire the image data repeatedly, the processing system <NUM> may control to the device <NUM> to transmit repeated pulses on the same aperture.

While the present disclosure describes embodiments related to intravascular ultrasound (IVUS) imaging using an intravascular catheter or guidewire, it is understood that one or more aspects of the present disclosure can be implemented in any suitable ultrasound imaging system, including a synthetic aperture ultrasound imaging system, a phased array ultrasound imaging system, or any other array-based ultrasound imaging system. For example, aspects of the present disclosure can be implemented in intraluminal ultrasound imaging systems using an intracardiac (ICE) echocardiography catheter and/or a transesophageal echocardiography (TEE) probe, and/or external ultrasound imaging system using an ultrasound probe configured for imaging while positioned adjacent to and/or in contact with the patient's skin. The ultrasound imaging device can be a transthoracic echocardiography (TTE) imaging device in some embodiments.

An ultrasound transducer array of ultrasound imaging device includes an array of acoustic elements configured to emit ultrasound energy and receive echoes corresponding to the emitted ultrasound energy. In some instances, the array may include any number of ultrasound transducer elements. For example, the array can include between <NUM> acoustic elements and <NUM> acoustic elements, including values such as <NUM> acoustic elements, <NUM> acoustic elements, acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, <NUM> acoustic elements, and/or other values both larger and smaller. In some instances, the transducer elements of the array may be arranged in any suitable configuration, such as a linear array, a planar array, a curved array, a curvilinear array, a circumferential array, an annular array, a phased array, a matrix array, a one-dimensional (1D) array, a <NUM>. x dimensional array (e.g., a <NUM>. 5D array), or a two-dimensional (2D) array. The array of transducer elements (e.g., one or more rows, one or more columns, and/or one or more orientations) can be uniformly or independently controlled and activated. The array can be configured to obtain one-dimensional, two-dimensional, and/or three-dimensional images of patient anatomy.

The ultrasound transducer elements may include piezoelectric/piezoresistive elements, piezoelectric micromachined ultrasound transducer (PMUT) elements, capacitive micromachined ultrasound transducer (CMUT) elements, and/or any other suitable type of ultrasound transducer elements. The ultrasound transducer elements of the array are in communication with (e.g., electrically coupled to) electronic circuitry. For example, the electronic circuitry can include one or more transducer control logic dies. The electronic circuitry can include one or more integrated circuits (IC), such as application specific integrated circuits (ASICs). In some embodiments, one or more of the ICs can include a microbeamformer (µBF). In other embodiments, one or more of the ICs includes a multiplexer circuit (MUX).

<FIG> is a schematic diagram of a processor circuit <NUM>, according to embodiments of the present disclosure. The processor circuit <NUM> may be implemented in the processing system <NUM> and/or the imaging device <NUM> of <FIG>. As shown, the processor circuit <NUM> may include a processor <NUM>, a memory <NUM>, and a communication module <NUM>. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The processor <NUM> may include a central processing unit (CPU), a digital signal processor (DSP), an ASIC, a controller, a field-programmable gate array (FPGA), another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein.

The memory <NUM> may include a cache memory (e.g., a cache memory of the processor <NUM>), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), flash memory, solid state memory device, hard disk drives, other forms of volatile and non-volatile memory, or a combination of different types of memory. In an embodiment, the memory <NUM> includes a non-transitory computer-readable medium. The instructions <NUM> may include instructions that, when executed by the processor <NUM>, cause the processor <NUM> to perform the operations described herein with reference to the processing system <NUM> and/or the imaging device <NUM> (<FIG>). Instructions <NUM> may also be referred to as code. The terms "instructions" and "code" should be interpreted broadly to include any type of computer-readable statement(s). For example, the terms "instructions" and "code" may refer to one or more programs, routines, sub-routines, functions, procedures, etc. "Instructions" and "code" may include a single computer-readable statement or many computer-readable statements.

The communication module <NUM> can include any electronic circuitry and/or logic circuitry to facilitate direct or indirect communication of data between the processor circuit <NUM>, the imaging device <NUM>, and/or the display <NUM>. In that regard, the communication module <NUM> can be an input/output (I/O) device. In some instances, the communication module <NUM> facilitates direct or indirect communication between various elements of the processor circuit <NUM> and/or the processing system <NUM> (<FIG>).

<FIG> is a diagrammatic top view of a portion of a flexible assembly <NUM>, according to aspects of the present disclosure. The flexible assembly <NUM> includes a transducer array <NUM> formed in a transducer region <NUM> and transducer control logic dies <NUM> (including dies 206A and 206B) formed in a control region <NUM>, with a transition region <NUM> disposed therebetween.

The transducer control logic dies <NUM> are mounted on a flexible substrate <NUM> into which the transducers <NUM> have been previously integrated. The flexible substrate <NUM> is shown in a flat configuration in <FIG>. Though six control logic dies <NUM> are shown in <FIG>, any number of control logic dies <NUM> may be used. For example, one, two, three, four, five, six, seven, eight, nine, ten, or more control logic dies <NUM> may be used.

The flexible substrate <NUM>, on which the transducer control logic dies <NUM> and the transducers <NUM> are mounted, provides structural support and interconnects for electrical coupling. The flexible substrate <NUM> may be constructed to include a film layer of a flexible polyimide material such as KAPTONTM (trademark of DuPont). Other suitable materials include polyester films, polyimide films, polyethylene napthalate films, or polyetherimide films, liquid crystal polymer, other flexible printed semiconductor substrates as well as products such as Upilex® (registered trademark of Ube Industries) and TEFLON® (registered trademark of E. In the flat configuration illustrated in <FIG>, the flexible substrate <NUM> has a generally rectangular shape. As shown and described herein, the flexible substrate <NUM> is configured to be wrapped around a support member <NUM> (<FIG>) in some instances. Therefore, the thickness of the film layer of the flexible substrate <NUM> is generally related to the degree of curvature in the final assembled flexible assembly <NUM>. In some embodiments, the film layer is between <NUM> and <NUM>, with some particular embodiments being between <NUM> and <NUM>, e.g., <NUM>.

The transducer control logic dies <NUM> is a non-limiting example of a control circuit. The transducer region <NUM> is disposed at a distal portion <NUM> of the flexible substrate <NUM>. The control region <NUM> is disposed at a proximal portion <NUM> of the flexible substrate <NUM>. The transition region <NUM> is disposed between the control region <NUM> and the transducer region <NUM>. Dimensions of the transducer region <NUM>, the control region <NUM>, and the transition region <NUM> (e.g., lengths <NUM>, <NUM>, <NUM>) can vary in different embodiments. In some embodiments, the lengths <NUM>, <NUM>, <NUM> can be substantially similar or, the length <NUM> of the transition region <NUM> may be less than lengths <NUM> and <NUM>, the length <NUM> of the transition region <NUM> can be greater than lengths <NUM>, <NUM> of the transducer region and controller region, respectively.

The control logic dies <NUM> are not necessarily homogenous. In some embodiments, a single controller is designated a master control logic die 206A and contains the communication interface for cable <NUM> which may serve as an electrical conductor, e.g., electrical conductor <NUM>, between a processing system, e.g., processing system <NUM>, and the flexible assembly <NUM>. Accordingly, the master control circuit may include control logic that decodes control signals received over the cable <NUM>, transmits control responses over the cable <NUM>, amplifies echo signals, and/or transmits the echo signals over the cable <NUM>. The remaining controllers are slave controllers 206B. The slave controllers 206B may include control logic that drives a transducer <NUM> to emit an ultrasonic signal and selects a transducer <NUM> to receive an echo. In the depicted embodiment, the master controller 206A does not directly control any transducers <NUM>. In other embodiments, the master controller 206A drives the same number of transducers <NUM> as the slave controllers 206B or drives a reduced set of transducers <NUM> as compared to the slave controllers 206B. In an exemplary embodiment, a single master controller 206A and eight slave controllers 206B are provided with eight transducers assigned to each slave controller 206B.

To electrically interconnect the control logic dies <NUM> and the transducers <NUM>, in an embodiment, the flexible substrate <NUM> includes conductive traces <NUM> formed in the film layer that carry signals between the control logic dies <NUM> and the transducers <NUM>. In particular, the conductive traces <NUM> providing communication between the control logic dies <NUM> and the transducers <NUM> extend along the flexible substrate <NUM> within the transition region <NUM>. In some instances, the conductive traces <NUM> can also facilitate electrical communication between the master controller 206A and the slave controllers 206B. The conductive traces <NUM> can also provide a set of conductive pads that contact the conductors <NUM> of cable <NUM> when the conductors <NUM> of the cable <NUM> are mechanically and electrically coupled to the flexible substrate <NUM>. Suitable materials for the conductive traces <NUM> include copper, gold, aluminum, silver, tantalum, nickel, and tin, and may be deposited on the flexible substrate <NUM> by processes such as sputtering, plating, and etching. In an embodiment, the flexible substrate <NUM> includes a chromium adhesion layer. The width and thickness of the conductive traces <NUM> are selected to provide proper conductivity and resilience when the flexible substrate <NUM> is rolled. In that regard, an exemplary range for the thickness of a conductive trace <NUM> and/or conductive pad is between <NUM>-<NUM>. For example, in an embodiment, <NUM> conductive traces <NUM> are separated by <NUM> of space. The width of a conductive trace <NUM> on the flexible substrate may be further determined by the width of the conductor <NUM> to be coupled to the trace/pad.

The flexible substrate <NUM> can include a conductor interface <NUM> in some embodiments. The conductor interface <NUM> can be a location of the flexible substrate <NUM> where the conductors <NUM> of the cable <NUM> are coupled to the flexible substrate <NUM>. For example, the bare conductors of the cable <NUM> are electrically coupled to the flexible substrate <NUM> at the conductor interface <NUM>. The conductor interface <NUM> can be tab extending from the main body of flexible substrate <NUM>. In that regard, the main body of the flexible substrate <NUM> can refer collectively to the transducer region <NUM>, controller region <NUM>, and the transition region <NUM>. In the illustrated embodiment, the conductor interface <NUM> extends from the proximal portion <NUM> of the flexible substrate <NUM>. In other embodiments, the conductor interface <NUM> is positioned at other parts of the flexible substrate <NUM>, such as the distal portion <NUM>, or the flexible substrate <NUM> may lack the conductor interface <NUM>. A value of a dimension of the tab or conductor interface <NUM>, such as a width <NUM>, can be less than the value of a dimension of the main body of the flexible substrate <NUM>, such as a width <NUM>. In some embodiments, the substrate forming the conductor interface <NUM> is made of the same material(s) and/or is similarly flexible as the flexible substrate <NUM>. In other embodiments, the conductor interface <NUM> is made of different materials and/or is comparatively more rigid than the flexible substrate <NUM>. For example, the conductor interface <NUM> can be made of a plastic, thermoplastic, polymer, hard polymer, etc., including polyoxymethylene (e.g., DELRIN®), polyether ether ketone (PEEK), nylon, Liquid Crystal Polymer (LCP), and/or other suitable materials.

<FIG> illustrates a perspective view of the device <NUM> with the scanner assembly <NUM> in a rolled configuration. In some instances, the assembly <NUM> is transitioned from a flat configuration (<FIG>) to a rolled or more cylindrical configuration (<FIG>). For example, in some embodiments, techniques are utilized as disclosed in one or more of <CIT>, titled "ULTRASONIC TRANSDUCER ARRAY AND METHOD OF MANUFACTURING THE SAME" and <CIT>, titled "HIGH RESOLUTION INTRAVASCULAR ULTRASOUND SENSING ASSEMBLY HAVING A FLEXIBLE SUBSTRATE".

In some embodiments, the transducer elements <NUM> and/or the controllers <NUM> can be positioned in in an annular configuration, such as a circular configuration or in a polygon configuration, around a longitudinal axis <NUM> of a support member <NUM>. It will be understood that the support member <NUM> may comprise, or be referred to as, a chassis. It will also be understood that the longitudinal axis <NUM> of the support member <NUM> may also be referred to as the longitudinal axis of the scanner assembly <NUM>, the flexible elongate member <NUM>, and/or the device <NUM>. For example, a cross-sectional profile of the imaging assembly <NUM> at the transducer elements <NUM> and/or the controllers <NUM> can be a circle or a polygon. Any suitable annular polygon shape can be implemented, such as a based on the number of controllers/transducers, flexibility of the controllers/transducers, etc., including a pentagon, hexagon, heptagon, octagon, nonagon, decagon, etc. In some examples, the plurality of transducer controllers <NUM> may be used for controlling the plurality of ultrasound transducer elements <NUM> to obtain imaging data associated with the vessel <NUM>.

The support member <NUM> can be referenced as a unibody or chassis in some instances. The support member <NUM> can be composed of a metallic material, such as stainless steel, or non-metallic material, such as a plastic or polymer as described in <CIT>, ('<NUM> Application). The support member <NUM> can be a ferrule having a distal flange or portion <NUM> and a proximal flange or portion <NUM>. The support member <NUM> can be tubular in shape and define a lumen <NUM> extending longitudinally therethrough. The lumen <NUM> can be sized and shaped to receive the guide wire <NUM>. The support member <NUM> can be manufactured using any suitable process. For example, the support member <NUM> can be machined and/or electrochemically machined or laser milled, such as by removing material from a blank to shape the support member <NUM>, or molded, such as by an injection molding process.

Referring now to <FIG>, shown there is a diagrammatic cross-sectional side view of a distal portion of the intraluminal imaging device <NUM>, including the flexible substrate <NUM> and the support member <NUM>, according to aspects of the present disclosure. The support member <NUM> can be referenced as a unibody or chassis in some instances. The support member <NUM> can be composed of a metallic material, such as stainless steel, or non-metallic material, such as a plastic or polymer as described in <CIT>. The support member <NUM> can be ferrule having a distal portion <NUM> and a proximal portion <NUM>. The support member <NUM> can define a lumen <NUM> extending along the longitudinal axis LA. The lumen <NUM> is in communication with the entry/exit port <NUM> and is sized and shaped to receive the guide wire <NUM> (<FIG>). The support member <NUM> can be manufactured according to any suitable process. For example, the support member <NUM> can be machined and/or electrochemically machined or laser milled, such as by removing material from a blank to shape the support member <NUM>, or molded, such as by an injection molding process. In some embodiments, the support member <NUM> may be integrally formed as a unitary structure, while in other embodiments the support member <NUM> may be formed of different components, such as a ferrule and stands <NUM>, <NUM>, that are fixedly coupled to one another. In some cases, the support member <NUM> and/or one or more components thereof may be completely integrated with inner member <NUM>. In some cases, the inner member <NUM> and the support member <NUM> may be joined as one, e.g., in the case of a polymer support member.

Stands <NUM>, <NUM> that extend vertically are provided at the distal and proximal portions <NUM>, <NUM>, respectively, of the support member <NUM>. The stands <NUM>, <NUM> elevate and support the distal and proximal portions of the flexible substrate <NUM>. In that regard, portions of the flexible substrate <NUM>, such as the transducer portion or region <NUM>, can be spaced from a central body portion of the support member <NUM> extending between the stands <NUM>, <NUM>. The stands <NUM>, <NUM> can have the same outer diameter or different outer diameters. For example, the distal stand <NUM> can have a larger or smaller outer diameter than the proximal stand <NUM> and can also have special features for rotational alignment as well as control chip placement and connection. To improve acoustic performance, any cavities between the flexible substrate <NUM> and the surface of the support member <NUM> are filled with a backing material <NUM>. The liquid backing material <NUM> can be introduced between the flexible substrate <NUM> and the support member <NUM> via passageways <NUM> in the stands <NUM>, <NUM>. In some embodiments, suction can be applied via the passageways <NUM> of one of the stands <NUM>, <NUM>, while the liquid backing material <NUM> is fed between the flexible substrate <NUM> and the support member <NUM> via the passageways <NUM> of the other of the stands <NUM>, <NUM>. The backing material can be cured to allow it to solidify and set. In various embodiments, the support member <NUM> includes more than two stands <NUM>, <NUM>, only one of the stands <NUM>, <NUM>, or neither of the stands. In that regard the support member <NUM> can have an increased diameter distal portion <NUM> and/or increased diameter proximal portion <NUM> that is sized and shaped to elevate and support the distal and/or proximal portions of the flexible substrate <NUM>.

The support member <NUM> can be substantially cylindrical in some embodiments. Other shapes of the support member <NUM> are also contemplated including geometrical, non-geometrical, symmetrical, non-symmetrical, cross-sectional profiles. As the term is used herein, the shape of the support member <NUM> may reference a cross-sectional profile of the support member <NUM>. Different portions the support member <NUM> can be variously shaped in other embodiments. For example, the proximal portion <NUM> can have a larger outer diameter than the outer diameters of the distal portion <NUM> or a central portion extending between the distal and proximal portions <NUM>, <NUM>. In some embodiments, an inner diameter of the support member <NUM> (e.g., the diameter of the lumen <NUM>) can correspondingly increase or decrease as the outer diameter changes. In other embodiments, the inner diameter of the support member <NUM> remains the same despite variations in the outer diameter.

A proximal inner member <NUM> and a proximal outer member <NUM> are coupled to the proximal portion <NUM> of the support member <NUM>. The proximal inner member <NUM> and/or the proximal outer member <NUM> can include a flexible elongate member. The proximal inner member <NUM> can be received within a proximal flange <NUM>. The proximal outer member <NUM> abuts and is in contact with the flexible substrate <NUM>. A distal member <NUM> is coupled to the distal portion <NUM> of the support member <NUM>. For example, the distal member <NUM> is positioned around the distal flange <NUM>. The distal member <NUM> can abut and be in contact with the flexible substrate <NUM> and the stand <NUM>. The distal member <NUM> can be the distal-most component of the intraluminal imaging device <NUM>.

One or more adhesives can be disposed between various components at the distal portion of the intraluminal imaging device <NUM>. For example, one or more of the flexible substrate <NUM>, the support member <NUM>, the distal member <NUM>, the proximal inner member <NUM>, and/or the proximal outer member <NUM> can be coupled to one another via an adhesive. The assembly <NUM> shown in <FIG> can be activated according to a pulse sequence or scan sequence to form coherent beams of ultrasound energy to generate an image.

As noted above, conventional IVUS imaging devices may include a support member or chassis, also referred as unibody or housing, that is formed of a metal tube and provides structural support, rigidity, radiopacity and other characteristics to the IVUS device. Conventional chassis suffer from a number of drawbacks. For example, the manufacturing techniques available for metals (e.g., milling, welding, etc.) limit the types of chassis and mechanical features that can be produced. Similarly, some metals cannot be re-flowed with polymers and/or do not effectively scatter or attenuate ultrasound waves. The present disclosure describes exemplary embodiments of a chassis formed of multiple materials that incorporates various mechanical and/or acoustic properties for improved performance of the IVUS device. In particular, the materials and constructions of the chassis described herein are selected to enhance or improve properties and characteristics such as strength, flexibility, maneuverability, resilience, acoustic performance, machineability, and/or radiopacity. It will be understood that, although the embodiments discussed below are described with respect to IVUS imaging catheters, it will be understood that the embodiments may be used with any suitable device configured to be inserted into a body lumen of a patient.

<FIG> provide various structural arrangements and embodiments of a multi-material support member or chassis used in an IVUS imaging catheter, according to aspects of the present disclosure. The chassis include a hollow inner member formed of a first material, and one or more structures (e.g., rings, sleeves, flexible components) formed of one or more different materials. It will be understood that the support members or chassis described below may be used with a scanner assembly, such as the scanner assembly <NUM> shown in <FIG>. In some aspects, the scanner assembly may comprise, or be referred to as an ultrasound transducer array, a flex circuit, an ultrasound transducer, acoustic assembly, and or an integrated circuit coupled to a substrate. A scanner assembly may be positioned around a perimeter of a chassis, and coupled to other components of a catheter, including a flexible inner member, a flexible outer member, and/or a flexible tip member.

<FIG> is perspective view of a chassis <NUM> configured to be used with a scanner assembly (e.g., scanner assembly <NUM>, <FIG>, <FIG>), the chassis <NUM> including a hollow cylindrical member <NUM> with two polymeric rings <NUM>, <NUM> attached around a perimeter of the hollow cylindrical member <NUM>. <FIG> is a perspective cross-sectional side view of the chassis <NUM> shown in <FIG> taken along section line <NUM>-<NUM>. In an exemplary embodiment, the hollow cylindrical member <NUM>, which may also be referred to as a hollow inner member, a cylindrical core member, a core, a metal core, or tube, may comprise, is formed of a metallic material. However, in other embodiments, the hollow cylindrical member <NUM> may comprise a polymer, ceramic, or other type of material. The two rings <NUM>, <NUM> may be referred to as annular members, in some aspects. In the illustrated embodiment, the two rings <NUM>, <NUM>, or annular members, comprise circular shapes. In other embodiments, the annular members <NUM>, <NUM>, comprise polygonal shapes, elliptical shapes, and/or combinations thereof. For example, in some embodiments, the annular members <NUM>, <NUM> comprise rectangular, hexagonal, octogonal, nonogonal, and/or any other suitable shapes. The two rings <NUM>, <NUM> may comprise, or may be formed of, a polymer-based material. In an exemplary embodiment, the metallic material of the cylindrical member <NUM>, or hollow core, comprises stainless-steel. However, other metallic materials may be used as well, including radiopaque materials such as platinum and iridium, tungsten, aluminum, and/or nitinol.

The hollow core <NUM> may provide structural support and/or protection for electrical components and sensitive materials on the scanner assembly. The hollow core <NUM> may comprise a cylindrical and/or annular cross-sectional shape. In some aspects, the hollow core <NUM> shown in <FIG> and <FIG> comprises a generally cylindrical shape. The generally cylindrical shape may be continuous, or may include grooves, through holes, or other features. Although the hollow core <NUM> comprises a cylindrical shape in <FIG>, the hollow core <NUM> may include other profiles or shapes, such as a polygon, rectangle, triangle, ellipse, and/or combinations thereof. In the illustrated embodiment, the hollow core <NUM> includes a uniform shape and uniform inner and outer diameters from the proximal end <NUM> to the distal end <NUM>. However, in some embodiments, the hollow core <NUM> comprises one or more non-uniform diameters, profiles, shapes, thicknesses, surfaces, or other features from the proximal end <NUM> to the distal end <NUM>. The hollow core <NUM> may comprise a section or length of an extruded tube, in some embodiments.

In the illustrated embodiment, the hollow core <NUM> has dimensions including inner diameter <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches), outer diameter <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches), thickness <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches), and length <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches). It will be understood that the ranges of the dimensions listed above are exemplary and may comprise other values, both larger and smaller than those listed. The two polymeric rings <NUM>, <NUM> are attached around the perimeter of the hollow core <NUM>. The polymeric rings <NUM>, <NUM> comprise structures of a material different from the material of the core <NUM>, and protrude radially outward from a perimeter of the core <NUM>. Each polymeric ring <NUM> and <NUM> includes a cylindrical, ring, and/or annular shape. In some aspects, the rings <NUM>, <NUM> may be described as washers. However, in other embodiments, one or both of the polymeric rings <NUM>, <NUM> may comprise other shapes or profiles, including polygons, such as octagons, nonagons, rectangles, triangles, or any combination thereof. Each polymeric ring <NUM> and <NUM> has dimensions including an inner diameter <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches), an outer diameter <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches), and a width <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches). In some aspects, the dimensions and values provided herein may be suitable for a catheter that accommodates a guidewire of up to <NUM> inches. However, it will be understood that these values are only exemplary and are not intended to limit the scope of the present disclosure. For example, the dimensions provided herein could be modified to accommodate guidewires or intraluminal devices of other sizes. For example, in some embodiments, the dimensions and values provided herein could be modified to accommodate a guidewire of up to <NUM> inches. In some embodiments, the support member is configured for applications without the use of a guidewire. Still other ranges are contemplated. For example, one or more of the exemplary dimensions provided above could be increased or decreased according to different diagnostic applications. For example, one or more of the dimensions (e.g., the upper bound and/or the lower bound) provided above could be modified by <NUM>. 5X, 2X, 3X, 5X, or any other suitable multiplier. In various embodiments, the intraluminal device can be used in coronary vasculature, peripheral vasculature, intracardiac applications, endoscopic applications, etc. The values of the noted and/or other dimensions of the intraluminal device can be selected according to the relatively larger or smaller dimensions of the body lumen in which the intraluminal device is to be positioned.

The material of each polymeric ring <NUM>, <NUM> may include a polymer-based material, a polymer-based composite, a polymer-based material reinforced with metal components or coatings, and/or any combination thereof. The material of each polymeric ring <NUM>, <NUM> may include conductive, radiopaque, and/or acoustic properties. The polymeric rings <NUM>, <NUM> provide support for the scanner assembly as it is wrapped into a cylindrical shape. The polymeric rings <NUM>, <NUM> may be attached onto the hollow core <NUM> by over-molding, by interference fit, adhesives, or any other suitable form of attachment. In one embodiment, the polymeric rings <NUM>, <NUM> are formed by extruding a tubing, cutting a length of the tubing, and sliding the cut portion of the tubing over the hollow core <NUM>. The two polymeric rings <NUM>, <NUM> may be secured onto the hollow core <NUM> by addition of adhesive at the ring-cylinder interface <NUM>. The adhesive can include polymer, metal, composite based material, or any combination thereof. The hollow core <NUM> as well as the polymeric rings <NUM>, <NUM> may include patterned surfaces with various geometric features and sizes to improve the attachment of the rings <NUM>, <NUM> to the hollow core <NUM>.

<FIG> is perspective view of a chassis <NUM> of a scanner assembly, according to one embodiment of the present disclosure. In some aspects, the chassis <NUM> includes features similar or identical to the chassis <NUM> of <FIG> and <FIG>, including a cylindrical hollow core <NUM> with two polymeric rings <NUM>, <NUM> positioned around a perimeter of the hollow core <NUM>. Referring to <FIG> and <FIG>, the chassis <NUM> further includes a polymeric inner member <NUM> positioned between the polymeric rings <NUM>, <NUM> and attached around the perimeter of the hollow core <NUM>. In some aspects the polymeric inner member <NUM> may be referred to as a sleeve member, or a sheath. <FIG> is a perspective cross-sectional side view of the chassis <NUM> shown in <FIG> taken along section line <NUM>-<NUM>. The chassis <NUM> includes the cylindrical hollow core <NUM> with two polymeric rings <NUM>, <NUM>. In some aspects, the hollow core <NUM> and/or polymeric rings <NUM>, <NUM> may comprise dimensions similar or identical to the chassis <NUM> shown in <FIG> and <FIG>. In the embodiment shown in <FIG> and <FIG>, the chassis <NUM> further comprises an inner member <NUM> formed between the two polymeric rings <NUM>, <NUM>, as illustrated in <FIG>. The inner member <NUM> has length <NUM>, which may range between <NUM>-<NUM> inches, and thickness <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches). The chassis <NUM> also includes a diameter, which may be similar or equal to that of the outer diameter <NUM> of chassis <NUM>. In the illustrated embodiment, the inner member <NUM> is formed as one integral assembly <NUM> with the two-polymeric rings <NUM>, <NUM>, which is over molded onto the cylindrical hollow core <NUM>. The inner member comprises a material that may be the same as the material of the polymeric rings <NUM>, <NUM>, or may comprise a different material. The integral assembly <NUM> forms an attachment or interface <NUM> with the cylindrical hollow core <NUM>. In some embodiments, the integral assembly <NUM> is formed my injection molding. In other embodiments, the integral assembly <NUM> is formed by extruding a tubing, cutting to length, machining to form rings <NUM>, <NUM>, and positioning the integral assembly <NUM> over the hollow core <NUM>. The integral assembly <NUM> may be coupled to the hollow core <NUM> using an interference fit, an adhesive, and/or any other suitable form of attachment. The adhesive may include polymeric, metallic, and/or composite based materials. In other embodiments, the inner member <NUM> may be formed as separate member from the rings <NUM>, <NUM>, forming an independent attachment or interface with the hollow core <NUM>. In some embodiments, the inner member <NUM> and/or integral assembly <NUM> includes a patterned inner and/or outer surface with various geometric features and sizes. The inclusion of the inner member <NUM> over the hollow core <NUM> may facilitate easier attachment and controlled spacing between multiple features (e.g., polymer rings <NUM>, <NUM>) onto to the chassis <NUM>. Although the inner member <NUM>, which may also be referred to as a sleeve member, comprises a circular or cylindrical shape in the illustrated embodiment, the inner member <NUM> may comprise other shapes or profiles, including polygonal, elliptical, and/or combinations thereof.

<FIG> is perspective view of a chassis <NUM> of a scanner assembly including cylindrical hollow core <NUM> with two polymeric rings <NUM>, <NUM> and inner pass-through holes <NUM> disposed around a perimeter of the hollow core. <FIG> is a perspective cross-sectional side view of the chassis <NUM> shown in <FIG> taken along section line <NUM>-<NUM>. The chassis <NUM> may include features similar or identical to the chassis <NUM> shown in <FIG>. Referring to <FIG> and <FIG>, the chassis <NUM> includes a cylindrical hollow core <NUM> with two polymeric rings <NUM>, <NUM> positioned around the perimeter of the hollow core <NUM>. The chassis <NUM> may include dimensions similar or identical to the chassis <NUM> shown in <FIG> and <FIG>. The chassis <NUM> shown in <FIG> and <FIG> further includes pass-through holes or grooves <NUM> disposed around the perimeter of the cylindrical hollow core <NUM>. The cylindrical hollow core <NUM> may include one, two, three, four, five, ten, fifteen, twenty, or any other suitable number of pass-through holes <NUM>, both greater and smaller. Each pass-through hole <NUM> includes a diameter <NUM>. In some embodiments, the diameters of each of the pass-through holes <NUM> are the same. In other embodiments, the diameter of at least one of the pass-through holes <NUM> differs from the diameter of another pass-through hole <NUM>. The presence of the pass-through holes <NUM> around the perimeter of the cylindrical hollow core <NUM> may serve as a mechanical interference point to aid with positioning and adhesion of other materials attached to the chassis <NUM>. In some embodiments, the chassis <NUM> includes grooves instead of holes, such that the grooves do not extend completely through the sidewall of the hollow core <NUM>.

Further, referring to <FIG>, the hollow core <NUM> includes recesses <NUM> extending inward from the outer surface of the hollow core <NUM>, at least partially around the perimeter of the hollow core <NUM>. In some aspects, inclusion of the recesses <NUM> on the outer surface of the cylindrical hollow core <NUM> may facilitate improved attachment or coupling of the polymer rings <NUM>, <NUM> onto the cylindrical hollow core <NUM>. For example, the recesses <NUM> may improve bonding of the polymer rings <NUM>, <NUM> to the hollow core <NUM>, and/or retain the polymer rings <NUM>, <NUM> at their respective longitudinal positions on the hollow core <NUM>. As described above, in some embodiments, the polymer rings <NUM>, <NUM> are over molded onto the hollow core <NUM> such that the polymer material of the rings <NUM>, <NUM> at least partially fills the recesses <NUM>.

<FIG> is perspective view of a chassis <NUM> of a scanner assembly, including a cylindrical hollow core <NUM> with two polymeric rings <NUM>, <NUM>, and an acoustic member <NUM>, which may also be referred to as a sleeve member or inner member, positioned around a middle or intermediate portion of the core <NUM>, extending at least partially around its perimeter. The intermediate portion or section is positioned between the distal and proximal portions or sections of the hollow core <NUM>. <FIG> is a perspective cross-sectional side view of the chassis <NUM> shown in <FIG> taken along section line <NUM>-<NUM>. <FIG> is a magnified, diagrammatic cross-sectional view of the chassis <NUM> shown in <FIG> taken along line <NUM>-<NUM>, showing recesses <NUM> and <NUM>. The chassis <NUM> can include some features and dimensions similar or identical to the chassis <NUM> shown in <FIG> and <FIG>, including the hollow core <NUM> and polymer rings <NUM>, <NUM>. The chassis <NUM> shown in <FIG> is formed with an inner member <NUM> disposed between the two polymeric rings <NUM>, <NUM>. In the illustrated embodiment, the length <NUM> of the inner member <NUM> extends approximately from a center of the cylindrical hollow core <NUM> to a location proximate the polymeric ring <NUM>. The inner member <NUM> can be positioned over an outer surface of the cylindrical hollow core <NUM> by over molding, coating, doping, or positioning a sleeve over the hollow core <NUM>. For example, in some embodiments, the hollow core <NUM> is placed into a mold and the inner member <NUM> is molded over the outer surface of the hollow core <NUM>. In other embodiments, a polymeric sleeve is positioned over the hollow core <NUM> and secured to the hollow core <NUM> by an adhesive. The adhesive can include polymer, metal, composite based materials or combination. The adhesive can improve the bonding at the inner member <NUM> and the surface of the cylindrical hollow core <NUM> forming the interface <NUM>. Although the inner member <NUM>, which may also be referred to as a sleeve member, comprises a circular or cylindrical shape in the illustrated embodiment, the inner member <NUM> may comprise other shapes or profiles, including polygonal, elliptical, and/or combinations thereof.

Referring to <FIG> and <FIG>, the interface <NUM> comprises a recess in the outer surface of the cylindrical hollow core <NUM>, the inner member <NUM> is positioned within the recess so that an outer surface of the inner member <NUM> is flush with the outer surface <NUM> of the cylindrical hollow core <NUM>, forming a smooth, or continuous outer profile of the combined hollow core <NUM> and inner member <NUM>. In that regard, the inner member <NUM> is continuous with the proximal and distal portions of the hollow member <NUM> so that they together form a continuous outer surface. The recesses <NUM>, <NUM> are formed such that they do not extend into the lumen <NUM> of the hollow core <NUM>. In other embodiments, the cylindrical hollow core <NUM> is not formed with a recess and the inner member <NUM> is positioned over the outer surface of the cylindrical hollow core <NUM> such that it is not flush with the outer surface <NUM> of the cylindrical hollow core <NUM>. In some aspects, the inclusion of the inner member <NUM> may provide improved acoustic properties and performance of the scanner assembly (e.g. backscattering and/or attenuation). The material and the thickness <NUM> of the inner member <NUM> may be selected to attain desired acoustic properties at the distal portion <NUM> of the chassis <NUM>. For example, the thickness <NUM> may range between <NUM>-<NUM> (<NUM>-<NUM> inches), and the material may comprise a polymer material such as Pebax® or polyimide.

Alternatively, an additional matching material may be incorporated at the interface between the inner member <NUM> and the cylindrical hollow core <NUM> surface in order to improve acoustic energy transmission for the scanner assembly <NUM> and the chassis <NUM>. The inner member <NUM> may also serve as a shock absorber for shock imposed on the scanner assembly by external or internal forces.

<FIG> is perspective view of a chassis <NUM> of a scanner assembly including the cylindrical hollow core <NUM>, two polymeric rings <NUM>, <NUM>, a flexible component <NUM> positioned at the proximal end <NUM>, and a flexible component <NUM> positioned at the distal end <NUM> of the hollow core <NUM> and around its perimeter. The flexible component <NUM> may be referred to as a proximal tubular member, and the flexible component <NUM> may be referred to as a distal tubular member <NUM>. <FIG> is a perspective cross-sectional view of the chassis <NUM> shown in <FIG> taken along section line <NUM>-<NUM>. The chassis <NUM> may include some features and dimensions similar or identical to the chassis <NUM> of <FIG>, including the hollow core <NUM> and the polymeric rings <NUM>, <NUM>. The chassis <NUM> shown in <FIG> and <FIG> further includes opposing flexible components <NUM>, <NUM> on the proximal end <NUM> and distal end <NUM> of the cylindrical hollow core <NUM>, respectively. The flexible component <NUM> comprises a tapered section 902a and a cylindrical section 906a, together forming the flexible component <NUM> as an integral component. Similarly, the flexible component <NUM> comprises a tapered section 902b and a cylindrical section 906b, together forming the flexible component <NUM> as an integral component. The tapered sections 902a and 902b shown in <FIG> and <FIG> comprise a tapering of the outer surface of the flexible components <NUM>, <NUM>, such that an inner diameter of each of the flexible components <NUM>, <NUM> remains constant or substantially constant across its length while the outer diameter decreases across its length. In other embodiments, the tapered sections 906a, 906b comprise a tapering of the outer and inner surfaces of the flexible components <NUM>, <NUM>. In other embodiments, the flexible components comprise a cylindrical shape along their entire lengths, and do not comprise tapered sections.

The flexible components <NUM>, <NUM> are coupled or attached to the hollow core <NUM> proximate to the respective ends of the hollow core <NUM>, and proximate to the respective polymeric rings <NUM>, <NUM>. Each of the cylindrical sections 906a, 906b includes an outer diameter <NUM>, which may range between <NUM>-<NUM> inches, and may be substantially equal in diameter as the hollow core <NUM>. Each of the cylindrical sections 906a, 906b includes a length <NUM>, which may range between <NUM>-<NUM> (<NUM>-<NUM> inches). The tapered sections 902a, 902b have end diameters <NUM>, which may be smaller than the diameter <NUM> of the hollow core <NUM>, and may range between <NUM>-<NUM> (<NUM>-<NUM> inches). The tapered sections have a length <NUM>, which may range between <NUM>-<NUM> (. <NUM>-<NUM> inches. The smaller diameter <NUM> may increase flexibility on each end <NUM>, <NUM> as a result of thinner sidewalls. In some aspects, the dimensions and values provided herein may be suitable for a catheter that accommodates a guidewire of up to <NUM> inches. However, it will be understood that these values are only exemplary and are not intended to limit the scope of the present disclosure. For example, the dimensions provided herein could be modified to accommodate guidewires or intraluminal devices of other sizes. For example, in some embodiments, the dimensions and values provided herein could be modified to accommodate a guidewire of up to <NUM> inches. Still other ranges are contemplated. For example, one or more of the exemplary dimensions provided above could be increased or decreased according to different diagnostic applications. For example, one or more of the dimensions provided above could be modified by <NUM>. 5X, 2X, 3X, 5X, or any other suitable multiplier.

The presence of the flexible components <NUM>, <NUM> may advantageously allow for a gradual transition in stiffness from the rigid stainless steel cylindrical member <NUM> to a flexible catheter and the , which may reduce the chance of kinking or damage to the intraluminal catheter. The flexible member <NUM> at the proximal end <NUM> of the chassis <NUM> may be coupled or attached to the inner and/or outer members of the catheter by one or more techniques, including thermal bonding, adhesives, interference fit, etc., and may function as strain relief and/or a transition in rigidity. The flexible member <NUM> at the distal end <NUM> of the chassis <NUM> may be coupled to attached to the hollow core <NUM> by one more techniques, including over molding, thermal bonding, adhesives, doping, coating, interference fit, etc., and may function as a transition in stiffness for the catheter tip. In the embodiment shown in <FIG> and <FIG>, the flexible components <NUM>, <NUM> are attached to the cylindrical hollow core <NUM> at each end <NUM>, <NUM>, such that the inner diameter <NUM> of the cylindrical hollow core <NUM> is constant or uniform across their respective lengths. The attachment of the flexible components <NUM>, <NUM> to the hollow core <NUM> forms interfaces <NUM>, <NUM> comprising respective mating surfaces between the metal core <NUM> and the flexible components <NUM>, <NUM>. In some aspects, the interfaces or attachments of the flexible components <NUM>, <NUM> may include other features, including recesses, grooves, holes, textured surfaces, and/or tapered surfaces that may improve mechanical strength and bonding. The chassis <NUM> advantageously includes multiple materials that may improve the functionality and mechanical performance of the device. For example, in some embodiments, a flexible component (e.g., <NUM>) over molded onto the hollow core <NUM> may replace a separate distal tip member as shown above in <FIG>, for example. In some embodiments, the surface finish of the inner lumen of the flexible components <NUM>, <NUM> may be selected to minimize friction with the guide wire.

<FIG> is a perspective view of a chassis <NUM> of a scanner assembly including a cylindrical hollow core <NUM> with a polymeric ring <NUM> and a flexible component <NUM> positioned around a perimeter of the hollow core <NUM>. <FIG> is a perspective cross-sectional view of the chassis <NUM> shown in <FIG> taken along section line <NUM>-<NUM>. The chassis <NUM> may include features and/or dimensions similar or identical to the chassis <NUM> of <FIG> and <FIG>, including a hollow core <NUM> and a ring member <NUM>. In the embodiment of <FIG> and <FIG>, the chassis <NUM> is formed with a flexible component <NUM> at the proximal end <NUM> and the flexible component <NUM> at the distal end <NUM>, where the flexible components comprise different geometries. In that regard, the flexible component <NUM> comprises a generally cylindrical body that includes an annular or cylindrical section <NUM> and a tapered or conical section <NUM> forming an integral component. The flexible component <NUM> may be referred to as a distal tip member. In some embodiments, the cylindrical section <NUM> may comprise a shape and dimensions similar to the polymeric ring <NUM>. For example, in some embodiments, the cylindrical section <NUM> includes an outer diameter that is similar or identical to the polymeric ring <NUM>. Flexible component <NUM> comprises a length <NUM>, with the cylindrical section <NUM> positioned around a distal portion of the hollow core <NUM>, and the tapered section <NUM> extending distally of the hollow core <NUM>. Flexible component <NUM> includes variable thicknesses <NUM>, <NUM>, <NUM>, along its length <NUM> while maintaining uniform cross-sectional inner diameter <NUM> (as shown in <FIG> and <FIG>). In that regard, the tapered section comprises a tapered outer surface such that the inner diameter <NUM> is constant along the length <NUM>. It will be understood that, in some embodiments, the inner surface may be tapered. In some embodiments, the outer surface is tapered while the thickness (<NUM>, <NUM>, <NUM>) of the flexible component <NUM> is constant along its length.

Referring to <FIG>, the flexible component <NUM> may be attached to the outer surface of the cylindrical hollow core <NUM> by over molding, mechanical attachment, interference fit, and/or an adhesive, and may fit in and/or around features of the hollow inner member <NUM>, including projections <NUM>. For example, the flexible member <NUM> may include a slot or recess in an inner surface of the flexible member <NUM> that is configured to fit over or around the projections <NUM> of the inner hollow member to retain the flexible component <NUM> in place. The unique attachment interface can improve adhesion of the flexible component <NUM> to the hollow inner member <NUM> and achieve functional objectives similar to those described above for other structures explained in <FIG>. The flexible component <NUM> includes an inner lumen <NUM> in communication with, or extending from, the lumen of the core member <NUM>, and may be configured to receive a guide wire.

At the proximal end <NUM>, the chassis <NUM> includes the flexible component <NUM>. In the illustrated embodiment, the flexible component <NUM> includes a generally cylindrical body defining a lumen <NUM> that includes a uniform on constant diameter along its length, and an outer profile that is uniform or constant along its length. A distal portion of the flexible component <NUM> is formed or positioned around the proximal end of the cylindrical hollow core <NUM>, the flexible component <NUM> is formed with optimized uniform thickness <NUM> and length <NUM> in order to achieve flexibility, radiopacity, acoustics and other properties to meet desired functional objectives.

<FIG> is a perspective cross-sectional side view of a chassis <NUM> of a scanner assembly including cylindrical hollow core <NUM> where the polymer ring <NUM> is attached around its perimeter using a lock-in feature or projection <NUM>. In the chassis <NUM> of <FIG>, the polymer ring <NUM> is attached to the surface of the cylindrical hollow core <NUM> by positioning the polymeric ring <NUM> over the corresponding projection <NUM>. The projection <NUM> may be positioned, locked-in, or press-fit into a corresponding recess or slot in the inner surface of the polymeric ring <NUM>. In some embodiments, the attachment shown in <FIG> may be achieved by forming the projections <NUM> on the hollow core <NUM>, and over molding the polymer ring <NUM> over the projection. This structural joining method can be applied to any of the structural embodiments presented above.

To fabricate the variously chassis embodiments disclosed herein, several different traditional and non-traditional manufacturing techniques may be used based on material, features and structure of the chassis, including injection molding, casting, 3D printing, laser cutting and texturing, extrusion, micro-machining, co-forming, re-flow, electron beam melting and/or other suitable techniques. It should be understood that no limitation to any particular manufacturing technology is intended or should be implied from the teachings of the disclosed principles.

The structure of the embodiments described above may be selected based on the size, functional objective, and/or type of scanner assembly. Thus, any advantageous structural arrangement with appropriate length, width, and height, may be employed, which could include not only the circular/cylindrical and semi-circular shapes discussed herein, but also triangular, conic, polygon and rectilinear shapes may also be employed. The chassis may include any number of polymeric rings such as one, two, three, five, ten, or any other suitable number, both greater and smaller. Further, the chassis may include variety of combinations of the features described above. All exemplary variations of the chassis from <FIG> may be coupled to a scanner assembly. The chassis advantageously incorporates variety of material properties and structures that can improve performance characteristics for a variety of catheters and intraluminal devices. In that regard, although the embodiments shown in <FIG> are described with respect to IVUS imaging catheters, it will be understood that the support member or chassis described above may be used with a variety of intraluminal devices, including intracardiac echocardiography (ICE) catheters, optical coherence tomography (OCT) catheters, sensing catheters, guide catheters, sensing guidewires, or any other suitable type of intraluminal device.

<FIG> illustrates a flow diagram illustrating an exemplary method <NUM> of forming a scanner assembly with a multi-material chassis. At step <NUM>, the method <NUM> includes defining a geometrical structure of the chassis for the type of scanner to be used and the desired functional objective. As shown in <FIG>, variety of structural geometries can compose the chassis based on the desired functionality.

At step <NUM>, the method <NUM> includes selecting an appropriate material for each component of the chassis. The material is selected based on the desired properties that the scanner assembly needs such as rigidity, opacity, flexibility, acoustic, machinability, moldability and combination thereof.

At step <NUM>, the method <NUM> includes defining the number of flexible components to be attached to a hollow core that will produce the desired functionality of the scanner assembly. This step <NUM> may include adding two or more polymer rings, a combination of two polymer rings and a flexible inner member, a polymer ring and a flexible component that serves as guidewire or any combination thereof.

At step <NUM>, the method <NUM> includes selecting a suitable manufacturing process to produce each component of the multi-material chassis such as selecting micro-machining to form hollow core component, selecting an over molding process to form the polymer rings over the hollow core component, and any other suitable manufacturing process corresponding to each component of the chassis.

At step <NUM>, the method <NUM> includes connecting all components to form the multi-material chassis. For example, in some embodiments the flexible components can be placed into a recess formed on the surface of the hollow core member, the flexible components can be press-fit into the hollow core member, or they can be applied via over molding as shown in <FIG>. At step <NUM>, once the multi-material chassis is formed it may be coupled to the scanner assembly.

Claim 1:
An intraluminal ultrasound imaging catheter (<NUM>), comprising:
a flexible elongate member configured to be positioned within a body lumen of a patient;
a support member (<NUM>) coupled to a distal portion of the flexible elongate member,
wherein the support member comprises:
a hollow inner member (<NUM>) comprising a first material;
a first annular member (<NUM>) positioned around a perimeter of the hollow inner member at a proximal portion of the hollow inner member, wherein the first annular member extends radially outward from the hollow inner member, and wherein the first annular member comprises a second material that is different from the first material; and
an ultrasound scanner assembly (<NUM>) positioned around the first annular member of the support member, wherein the ultrasound scanner assembly is configured to obtain ultrasound imaging data of the body lumen;
characterized in the support member further comprising a sleeve member (<NUM>) positioned around the perimeter of the hollow inner member at an intermediate portion of the inner hollow member,
wherein the sleeve member is positioned distal of the first annular member, and
wherein the sleeve member comprises a third material.