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 a treatment's 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.

Existing solid-state devices present several challenges. The electrical cable is attached to a flex circuit of an IVUS imaging assembly close to electronic components. Attaching the cables in such close proximity can potentially harm operation of the electronic components. The cable connection also increases the stiff length at the distal portion of a catheter, which reduces the catheter's ability to traverse tortuous vasculature without damage to electrical traces. Additionally, the difference in rigidity between the distal imaging assembly and the flexible catheter body creates a weak point in the construction of the IVUS imaging device that is susceptible to kinks and bends. The stress and strain at these kinks and bends can increase the result of material failure, as well as breakage of the electrical conductors and connects with the flex circuit. Ensuring that conductive traces formed in the flex circuit stay operational while being handled during the manufacturing process is also a challenge. Assembly of a solid-state IVUS device sometimes involves rolling a flex circuit around the circumference of the catheter. Such steps during the manufacturing can be difficult to automate in a reproducible manner because of the added thickness of some portions of the flex circuit.

Document <CIT> describes an intraluminal imaging device comprising ultrasound imaging assembly with a flexible substrate.

An intraluminal imaging device, such as an intravascular ultrasound (IVUS) imaging catheter, is described herein. The ultrasound imaging assembly at the distal portion of the catheter includes a flexible substrate rolled into a substantially cylindrical form. The flexible substrate has a distal portion with acoustic elements positioned thereon, as well as a proximal portion including weld pads to which electrical conductors are attached. Electrical traces formed on the flexible substrate connect the ultrasound imaging assembly to the weld pads. When the catheter is subjected to bending, the resulting strain on the flexible substrate can cause fracturing of one or more electrical traces, leading to a failure of the imaging catheter. Disclosed are flexible substrates and electrical traces that include strain relief features to minimize the probability of fracturing an electrical trace when the catheter is bent.

The flex circuit substrate disclosed herein has particular, but not exclusive, utility for intraluminal medical devices such as catheters and guidewires. One general aspect of the flex circuit substrate includes an intraluminal ultrasound imaging device. The intraluminal ultrasound imaging device also includes a flexible elongate member configured to be positioned within a body lumen of a patient; and an ultrasound imaging assembly coupled to a distal portion of the flexible elongate member and including: a flexible substrate including a scanner body portion and an attachment portion extending proximally from the scanner body portion, where the attachment portion defines a curved path including a first curve curving in a first direction and a second curve curving in a different second direction; one or more control circuits mounted on the scanner body portion; one or more transducer elements mounted on the scanner body portion and in communication with the one or more control circuits; and a plurality of conductive traces disposed on the attachment portion, where the plurality of conductive traces is in electrical communication with the one or more control circuits, where the plurality of conductive traces follows the curved path of the attachment portion, and where each conductive trace includes a pattern that bends relative to the curved path of the attachment portion. Other embodiments of this aspect may include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform actions of the methods.

Implementations may include one or more of the following features. In some embodiments, the curved path includes a horseshoe shape. In some embodiments, the curved path includes a serpentine shape. In some embodiments, the pattern of each conductive trace includes a sinusoidal shape. In some embodiments, the pattern of each conductive trace includes a braided shape. In some embodiments, the pattern of each conductive trace includes redundant zig-zag patterns periodically connected to one another. In some embodiments, the flexible elongate member includes an inner member, where a proximal region of the attachment portion is attached to the inner member, and where an intermediate region of the attachment portion is detached from the inner member such that the intermediate region of the attachment portion is configured to move relative to the inner member. In some embodiments, a width of the proximal region of the attachment portion is greater than a width of the intermediate region of the attachment portion. In some embodiments, the flexible elongate member further includes an outer member positioned around the inner member and the attachment portion of the flexible substrate, where the outer member retains the attachment portion of the flexible substrate in a rolled configuration such that the attachment portion is disposed around at least a portion of a circumference of the inner member and within an annular space between the inner member and the outer member. In some embodiments, the proximal region of the attachment portion includes a plurality of electrical contacts coupled to the plurality of conductive traces, where the plurality of conductors are electrically connected to the plurality of conductive traces via the plurality of electrical contacts. In some embodiments, the plurality of conductors extends within the annular space between the inner member and the outer member. In some embodiments, the flexible elongate member includes a longitudinal axis, and the proximal region of the attachment portion includes a rectangular shape and is aligned with the longitudinal axis. In some embodiments, a region of the attachment portion between the first and second curve is oriented at an angle of <NUM>-<NUM> degrees relative to the longitudinal axis. In some embodiments, the scanner body portion is positioned around the rigid tubular member. In some embodiments, the attachment portion is positioned proximally of the one or more transducer elements and the one or more control circuits. In some embodiments, the attachment portion extends proximally of the rigid tubular member. In some embodiments, a width of the scanner body portion is greater than a width of the attachment portion.

One general aspect includes an intravascular ultrasound (IVUS) imaging catheter. In some embodiments, the intravascular ultrasound also includes a flexible elongate member configured to be positioned within a blood vessel of a patient, the flexible elongate member including a longitudinal axis. In some embodiments, the intravascular ultrasound also includes an ultrasound scanner assembly coupled to a distal portion of the flexible elongate member and including: a flexible substrate including a scanner body portion and an attachment portion extending proximally from the scanner body portion; a plurality of control circuits mounted on the scanner body portion; a plurality of transducer elements mounted on the scanner body portion and in communication with the plurality of control circuits, where the plurality of transducer elements is disposed in a circumferential arrangement around the longitudinal axis; and a plurality of conductive traces disposed on the attachment portion and in electrical communication with the plurality of control circuits. In some embodiments, the attachment portion includes a first curve curving in a first direction and a second curve curving in a different second direction, the first curve and second curve defining a curved path. In some embodiments, the plurality of conductive traces follows the curved path. In some embodiments, each conductive trace includes a pattern that bends relative to the curved path.

An intraluminal imaging device, such as an intravascular ultrasound (IVUS) imaging catheter, is described herein. The ultrasound imaging assembly at the distal portion of the catheter includes a flexible substrate. The flexible substrate has a distal portion with acoustic elements positioned thereon, as well as a proximal portion including weld pads to which electrical conductors are attached. Electrical traces formed on the flexible substrate connect the ultrasound imaging assembly to the weld pads. As part of the manufacturing process, the flexible substrate is rolled into a cylindrical shape around a rigid tubular body or ferrule. Further, a proximal attachment portion of the flexible substrate is coupled to a flexible inner catheter member. The proximal attachment portion has electrical contacts or pads that are connected to electrical conductors that extend along a length of catheter body. However, the catheter may be subjected to bending, either during the manufacturing process, during normal handling, or during navigation through anatomy such as the tortuous pathways of a human vascular system. Such bending can cause strain on the flexible substrate, particularly to the proximal attachment portion, which can in turn lead to fracturing of one or more electrical traces, resulting in a failure of the imaging catheter. Disclosed are flexible substrates and electrical traces that include strain relief features to minimize the chance of an electrical trace fracturing when the catheter is bent.

<FIG> is a diagrammatic schematic view of an ultrasound imaging system <NUM>, in accordance with 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 an 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 or scanner body <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 or scanner body <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>. Generally, the device <NUM> can be utilized within any suitable anatomy and/or body lumen of the patient. The processing system <NUM> outputs image data such that an image of the vessel or lumen <NUM>, such as a cross-sectional IVUS image of the lumen <NUM>, is displayed on the monitor <NUM>. Lumen <NUM> may represent fluid filled or surrounded structures, both natural and man-made. Lumen <NUM> may be within a body of a patient. Lumen <NUM> may be a blood vessel, such 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 Volcano Corporation 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> within a flexible elongate member <NUM>. It is understood that any suitable gauge wire can be used for the transmission line bundle <NUM>. In an embodiment, the transmission line bundle <NUM> can include a four-conductor transmission line arrangement with, e.g., <NUM> American wire gauge (AWG) gauge wires. In an embodiment, the cable <NUM> can include a seven-conductor transmission line arrangement utilizing, e.g., <NUM> AWG gauge wires. In some embodiments, <NUM> AWG gauge 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.

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 comprise 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 comprise a microbeamformer (µBF). In other embodiments, one or more of the ICs comprises a multiplexer circuit (MUX).

<FIG> is a diagrammatic top view of a portion of a scanner assembly or scanner body <NUM> formed on a flexible substrate <NUM>, in accordance with to aspects of the present disclosure. The scanner assembly or scanner body <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. In some embodiments, the scanner assembly or scanner body <NUM> is substantially rectangular in form when in a flat, unrolled state.

The transducer control logic dies <NUM> are mounted on the 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 KAPTON™ (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 and flexibility 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 transmission line bundle or cable <NUM> which may serve as electrical conductor(s), e.g., electrical conductor(s) <NUM>, between a processing system, e.g., processing system <NUM>, and the flexible scanner assembly <NUM>. Accordingly, the master control circuit may include control logic that decodes control signals received over the cable or transmission line bundle <NUM>, transmits control responses over the cable <NUM>, amplifies echo signals, and/or transmits the echo signals over the cable or transmission line bundle <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 transmission line bundle or cable <NUM> can include a plurality of conductors, including one, two, three, four, five, six, seven, or more conductors <NUM>.

The flexible substrate <NUM> can include a conductor interface <NUM> in some embodiments. In some cases, the conductor interface <NUM> may be referred to as an attachment portion, connection portion, tail, tail portion, weld leg, flex tail, etc. The conductor interface <NUM> (also referred to as an attachment portion <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 a 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 ultrasound scanner assembly <NUM> in a rolled configuration, in accordance with aspects of the present disclosure. In some instances, the assembly <NUM> is transitioned from a flat configuration (as shown for example in <FIG>) to a rolled or more cylindrical configuration (as shown for example in <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 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 intraluminal imaging 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 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.

<FIG> shows 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>, in accordance with aspects of the present disclosure. The support member <NUM> can be referenced as a unibody 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 or flange <NUM> and a proximal or flange portion <NUM>. The support member <NUM> can define a lumen <NUM> extending along the longitudinal axis. The lumen <NUM> is in communication with the entry/exit port <NUM> and is sized and shaped to receive the guide wire <NUM> (as shown for example in <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 or unibody 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 an inner member or guide wire 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 <NUM> (or transducer 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.

An inner member <NUM> and a proximal outer member <NUM> are coupled to the proximal portion <NUM> of the support member <NUM>. The inner member or guide wire member <NUM> and/or the proximal outer member <NUM> can comprise a flexible elongate member. The inner member <NUM> can be received within a proximal flange <NUM>, or may terminate within the support member <NUM>, or may extend entirely through the support member <NUM> and project out through the distal portion or 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 inner member <NUM>, and/or the proximal outer member <NUM> can be coupled to one another via an adhesive.

The flexible substrate <NUM> includes a conductor interface <NUM>, which may also be referred to as an attachment portion. The attachment portion <NUM> may have the form of a tail or leg extending proximally of a scanner portion of the flexible interface <NUM>. The attachment portion extends within an annular space created by the inner member <NUM> and the outer member <NUM>, and is coupled to the inner member <NUM>. In some embodiments, the attachment portion <NUM> is adhered, welded, tacked, or otherwise connected to the inner member <NUM> at one or more attachment locations. As described below, in some embodiments, the attachment portion <NUM> comprises a plurality of curves. A curved segment of the attachment portion <NUM> can be at least partially wrapped around the inner member <NUM>. In an exemplary embodiment, at least a portion of the curved segment is not adhered or affixed to the inner member <NUM> so that the curved segment of the attachment portion <NUM> is allowed to move and flex relative to the inner member <NUM> while the device <NUM> is being assembled or navigated through the vasculature.

<FIG> is an elevation view of an ultrasound imaging assembly <NUM> with a distal portion of a flexible substrate <NUM> in a rolled configuration around the support member <NUM>, in accordance with aspects of the present disclosure. The flexible scanner assembly <NUM> has been wrapped around the support member <NUM> (e.g., a ferrule, metal tube, unibody, or other suitable structure) such that the control region <NUM>, transition region <NUM>, and transducer region <NUM> have taken a cylindrical shape around the support member <NUM>. In some instances, the control region <NUM>, transition region <NUM>, and transducer region <NUM> can be referenced as a distal portion or scanner body portion of the flexible substrate <NUM>. Also visible is the conductor interface or attachment portion <NUM>, which includes conductive traces <NUM> and conductive weld pads or solder pads <NUM> to which may be attached the conductors <NUM> that form the cable <NUM>. In some instances, the conductor interface <NUM> can be referenced as a proximal portion of the flexible substrate <NUM>. The conductive traces <NUM> in the conductor interface or attachment portion <NUM> establish electrical communication between the weld pads <NUM> and the controller region <NUM>. In order to prevent heat damage to the scanner assembly <NUM> when conductors <NUM> are welded or soldered to the conductive pads <NUM>, the conductor interface <NUM> projects away from the control region <NUM> of the scanner assembly <NUM> for some distance.

The cable <NUM> includes a plurality of conductors <NUM> extending along a length of the flexible elongate member (e.g., flexible elongate member <NUM> as shown for example in <FIG>). A proximal region of the attachment portion comprises the plurality of electrical contacts or weld pads <NUM> that are coupled to the plurality of conductive traces <NUM>. The plurality of conductors <NUM> are electrically connected to the plurality of conductive traces <NUM> via the plurality of electrical contacts or weld pads or solder pads <NUM>. The cable <NUM> formed by the plurality of electrical conductors <NUM> extends within an annular space between the inner member <NUM> and the outer member (e.g., outer member <NUM> as shown for example in <FIG>). The proximal region of the attachment portion comprises a generally rectangular shape and is aligned with the longitudinal axis of the flexible elongate member. The scanner body portion or scanner assembly <NUM> of the device (e.g., device <NUM> as shown for example in <FIG>) is positioned around the rigid tubular member or support member <NUM>. The attachment portion <NUM> extends proximally of the rigid tubular member, the one or more transducer elements of the transducer region <NUM>, and the one or more control circuits of the control region <NUM>.

<FIG> is a diagrammatic view of a flex circuit attachment portion <NUM> rolled around an inner member (not pictured) and positioned within an outer member <NUM>, in accordance with at aspects of the present disclosure. As the outer member <NUM> is bent (e.g., while navigating tortuous pathways of a human vascular system), the attachment portion <NUM> experiences areas of low stress <NUM>, areas of moderate stress <NUM>, and areas of high stress <NUM>.

<FIG> is a diagrammatic view of a flexible substrate <NUM> in an unrolled or flat state, in accordance with at least one embodiment of the present disclosure. Visible are the transducer region <NUM>, transition region <NUM>, and control region <NUM> of the scanner body portion <NUM>, and the attachment portion or weld leg <NUM> extending proximally from the scanner body portion <NUM>, and including a plurality of conductive traces <NUM> that connect a plurality of weld pads <NUM> to one or more control circuits of the control region <NUM>. The attachment portion <NUM> is substantially rectangular and substantially aligned with the longitudinal axis <NUM> of the flexible elongate member (e.g., the longitudinal axis of the inner member <NUM> as shown for example in <FIG>), and includes a proximal portion <NUM>, where the weld pads are located, and an intermediate portion <NUM>, and a distal portion <NUM>. The intermediate portion <NUM> defines a curved path which, in the example shown in <FIG>, comprises a first curve 736a in a first direction and a second curve 736b in a second (e.g., opposite) direction, thus forming a bend <NUM>. A greater or lesser number of curves may be provided instead or in addition. This curved path may for example be described as a C-shape, D-shape, S-shape, horseshoe shape, a serpentine shape, a sinusoidal shape, a zig-zag shape, a braided shape, or a strain-relief shape. The first and second curves 736a, 736b may each for example be oriented at angles of <NUM>-<NUM> degrees relative to the longitudinal axis <NUM>.

In some embodiments, the conductive traces <NUM> follow the curved path of the attachment portion <NUM>. In some embodiments, the width of the proximal region <NUM> of the attachment portion <NUM> is greater than a width of the intermediate region <NUM> and distal region <NUM>. In some embodiments, the width <NUM> of the scanner body portion <NUM> is greater than the width <NUM> of the attachment portion <NUM>.

<FIG> is a diagrammatic view of the flex circuit <NUM> of <FIG> wrapped cylindrically around a ferule, unibody, or support member <NUM> and an inner member <NUM> of the flexible elongate member, in accordance with at least one embodiment of the present disclosure. In the example shown in <FIG>, the proximal region <NUM> of the attachment portion <NUM> is attached to the inner member (e.g., with adhesive, caulk, or heat shrink tubing), while the distal region <NUM> of the attachment portion <NUM> is attached to the scanner body portion <NUM>, which is attached to the support member <NUM>. However, in some embodiments, at least the intermediate region <NUM> of the attachment portion <NUM> is detached from the inner member <NUM>, and capable of flexing, stretching, rotating, or translating with respect to the inner member <NUM>, e.g., when the inner member <NUM> is bent. Such bending may occur for example as the flexible elongate member is navigated through the tortuous pathways of a human vascular system, or other anatomical system. In some embodiments, an outer tubular member, such as the outer member <NUM> shown in <FIG>, is placed around the attachment portion <NUM> and abuts a proximal end of the scanner body portion <NUM>. Accordingly, the attachment portion <NUM> is positioned within an annular space defined by the inner member <NUM> and the outer member <NUM>.

<FIG> is a is a diagrammatic view of a curved flex circuit attachment portion <NUM> rolled around the inner member <NUM> (not pictured) and positioned within an outer member <NUM>, in accordance with at least one embodiment of the present disclosure. As the outer member <NUM> is bent to the same degree as shown in <FIG> (e.g., while navigating tortuous pathways of a human vascular system), the attachment portion <NUM> experiences areas of low stress <NUM>, and areas of moderate stress <NUM>. In this example, unlike the attachment portion <NUM> shown in the example of <FIG>, the attachment portion <NUM> of <FIG> shows no regions of high stress. This is possible because the curved (e.g., horseshoe-curved) shape of the intermediate region <NUM> of the attachment portion <NUM> makes it possible for the intermediate region <NUM> to bend, flex, rotate, and translate with respect to the inner member <NUM> (not pictured).

<FIG> is a schematic representation of an electrical trace <NUM> of the flex circuit attachment portion <NUM> or attachment portion <NUM>, in accordance with at least one embodiment of the present disclosure. A dark color <NUM> indicates regions of the electrical trace <NUM> which are subject to fracture when the attachment portion <NUM> or <NUM> is bent around a Y-axis after having been rolled around an X-axis (e.g., rolled around the inner member <NUM> as shown for example in <FIG>, and bent within the outer member <NUM> as shown for example in <FIG>). Because the electrical trace <NUM> is of uniform width, it is capable of fracturing across its entire width, thus breaking electrical continuity between a proximal side <NUM> of the attachment portion <NUM> and a distal side <NUM> of the attachment portion <NUM>. Such a break in electrical continuity may result in a non-functional device. Furthermore, because the electrical trace <NUM> is straight, it does not include any strain relief features, and is therefore equally capable of fracturing at any point along its length. Therefore, the dark color <NUM> covers the entirety of the electrical trace <NUM>.

The electrical trace may for example be a <NUM>-micron to <NUM>-micron thick layer <NUM> of copper, nickel, or gold, or combinations thereof, deposited on top of a <NUM> nanometer to <NUM> nanometer thick adhesion layer <NUM> such as titanium or tungsten, or combinations thereof.

<FIG> is a schematic representation of a hex-pattern electrical trace <NUM> of a flex circuit attachment portion <NUM>, in accordance with at least one embodiment of the present disclosure. The electrical trace <NUM> includes a plurality of openings <NUM> (e.g., hexagonal openings) that define two different, interconnected pathways 1120a and 1120b (e.g., hex-shaped or zig-zag pathways). A dark color <NUM> indicates regions of the electrical trace <NUM> which are subject to fracture when the attachment portion <NUM> is bent (e.g., to an angle θ around a Y-axis as shown). Because the electrical trace <NUM> is of non-uniform width and includes two separate interconnected pathways 1120a and 1120b, it is capable of fracturing across its entire width only in the regions where it is straight. In other regions, the openings <NUM> and interconnected alternating zig-zag pathways 1120a and 1120b are capable of acting as strain relief features, such that when the attachment portion <NUM> is rolled and bent, any fractures that occur are unlikely to cross the entire width of the electrical trace <NUM>. Thus, the dark color <NUM> indicates a probability of fracture only in certain portions of each pathway, thus making it probable that a fracture in the electrical trace <NUM> will not fully interrupt electrical continuity between the proximal side <NUM> and distal side <NUM> of the attachment portion <NUM>. If electrical continuity can be maintained despite bending of the attachment portion <NUM>, the electrical trace <NUM> of <FIG> may more durable than the electrical trace <NUM> of <FIG> when faced with the same degree of bending.

Because it can be more robust, the electrical trace may in some cases comprise a conductive layer copper, nickel, or gold, or may comprise only an adhesion layer of metals such as titanium, tungsten, or combinations thereof. The metal mass of the trace <NUM> must be sufficient to carry any required electrical signals without overheating. However, within this constraint, because thin metal traces may be more flexible and/or stretchable than thick ones, it may be advantageous to minimize the mass, width, or thickness of the trace <NUM>, in order to minimize the chance of fracture.

<FIG> is a schematic representation of a repeating horseshoe-pattern or sinusoidal-pattern electrical trace <NUM> of a flex circuit attachment portion <NUM>, in accordance with at least one embodiment of the present disclosure. The electrical trace <NUM> includes a plurality of <NUM>-degree horseshoe bends <NUM> that define a single pathway for the electrical trace <NUM>. A dark color <NUM> indicates regions of the electrical trace <NUM> which are subject to fracture when the attachment portion <NUM> is bent. Because the electrical trace <NUM> is of uniform width it is capable of fracturing across its entire width in certain regions. In other regions, the horseshoe bends <NUM> are capable of acting as strain relief features, such that when the attachment portion <NUM> is rolled and bent, fracture is unlikely in some (uncolored) regions <NUM> of the trace. Thus, the dark color <NUM> indicates a probability of fracture only in certain portions of the pathway, thus making it less probable that a fracture in the electrical trace <NUM> will fully interrupt electrical continuity between the proximal side <NUM> and distal side <NUM> of the connection region <NUM>.

<FIG> is a schematic representation of a plurality of zig-zag pattern electrical traces <NUM> of a flex circuit attachment portion <NUM>, in accordance with at least one embodiment of the present disclosure. The electrical traces <NUM> each include a plurality of zig-zag bends <NUM> that define a single pathway for each electrical trace <NUM>. Each zig-zag bend includes rounded corners <NUM>, which may be desirable as cracks in the conductive trace <NUM> may be less likely to form and propagate at a rounded corner <NUM> than at a sharp, angular one. In some embodiments, each conductive trace <NUM> leads to a single electrical contact or weld pad. In some embodiments, the plurality of zig zag traces <NUM> form a single conductor path of multiple redundant, co-extensive traces leading to a single weld pad.

<FIG> is a schematic representation of a plurality of electrical traces <NUM> of a flex circuit attachment portion <NUM>, in accordance with at least one embodiment of the present disclosure. The electrical traces <NUM> each include a plurality of bends <NUM> that combine elements of a sinusoidal and a zig-zag arrangement with rounded corners. Each trace <NUM> also includes a plurality of openings <NUM> that define two redundant but interconnected pathways 1420a and 1420b for each electrical trace <NUM>. In some embodiments, the openings <NUM> have rounded corners or a zig-zag or sinusoidal shape, or combinations thereof.

<FIG> is a schematic representation of a plurality of brick-patterned electrical traces <NUM> of a flex circuit attachment portion <NUM>, in accordance with at least one embodiment of the present disclosure. In some aspects, the brick patterned electrical traces <NUM> may be referred to as a braided pattern of electrical traces. The electrical traces <NUM> each include a plurality of zig-zags <NUM> and (e.g., rectangular) openings <NUM> that define two redundant but interconnected pathways 1420a and 1420b for each electrical trace <NUM>. Thus, the pattern of alternating curves comprises redundant zig-zag patterns periodically connected to one another. In some embodiments, the zig-zags <NUM> and openings <NUM> have sharp corners as shown. In other embodiments, the zig-zags <NUM> and/or openings <NUM> have rounded corners or sinusoidal shapes, or combinations thereof.

<FIG> is a top view of a curved intermediate region <NUM> of a flex circuit attachment portion <NUM> in a flattened (unrolled) state, in accordance with at least one embodiment of the present disclosure. The intermediate region <NUM> has a strain-relieving bend <NUM> resulting in a shape for the intermediate region <NUM> that may be variously described as C-shaped, horseshoe-shaped, serpentine, strain-relieving, or otherwise. In some instances, multiple C-shapes may be employed, either facing the same direction or facing in different directions. It should be understood that other numbers of bends may be used instead or in addition, resulting in shapes for the intermediate region <NUM> that may be variously described as sinusoidal, S-shaped, or otherwise. In some embodiments, other strain-relieving shapes for the intermediate region <NUM> may be used instead or in addition, including but not limited to dogleg, zig-zag, lightning bolt, or polygon shapes. The intermediate region <NUM> of the flex circuit connection portion also includes a plurality of sinusoidal conductive traces <NUM> following the contour or curved path of the intermediate region <NUM>, each comprising a plurality of strain-relieving <NUM>-degree bends <NUM>, or a combination of other bends resulting in the sinusoidal shape. The conductive traces <NUM> alternate or bend relative to the curved path of the intermediate region <NUM> of the attachment portion <NUM>. The combination of strain-relieving bends <NUM> in the traces <NUM> and a strain-relieving shape for the intermediate region <NUM> may minimize the risk of a failure-inducing trace fracture more than would either of these features alone.

<FIG> is a top view of a curved intermediate region <NUM> of a flex circuit attachment portion <NUM> in a flattened (unrolled) state, in accordance with at least one embodiment of the present disclosure. As with the example in <FIG>, the intermediate region <NUM> has a strain-relieving bend <NUM>, or series of bends, resulting in a shape for the intermediate region <NUM> that may be variously described as C-shaped, horseshoe-shaped, strain-relieving, or otherwise. In some embodiments, other strain-relieving shapes for the intermediate region <NUM> may be used instead or in addition, including but not limited to S-shaped, sinusoidal, dogleg, zig-zag, lightning bolt, or polygonal.

The intermediate region <NUM> of the flex circuit connection portion also includes a plurality of conductive traces <NUM> following the shape of the intermediate region <NUM>. Each conductive trace <NUM> comprises a plurality of strain-relieving chevron shapes <NUM>. Each chevron shape <NUM> includes a chevron-shaped opening <NUM> that defines two redundant but interconnected pathways 1720a and 1720b. Thus, the pattern of alternating curves comprises redundant zig-zag patterns periodically connected to one another. In an example, the chevrons <NUM> and chevron-shaped openings <NUM> are rounded such that they include no sharp corners that might facilitate the initiation or propagation of cracks in the traces <NUM>. In some embodiments, the chevrons <NUM> of a given conductive trace <NUM> face in an opposite direction to the chevrons <NUM> of immediately neighboring traces <NUM>.

The arrangement shown in <FIG> includes strain-reliving features both in the intermediate region <NUM> of the attachment portion <NUM> and in the traces <NUM> that follow the contours of the intermediate region <NUM>. The traces <NUM> further include a plurality of redundant, interconnected pathways 1720a and 1720b. In some embodiments, the width and thickness of the pathways is sufficient to carry the electrical signals necessary to operate the scanner body <NUM>, but not large enough to substantially increase the risk of crack formation and propagation. In an example, the traces <NUM> are between <NUM> and <NUM> micrometers wide, and spaced <NUM> to <NUM> micrometers apart. In another example, the traces <NUM> are <NUM> micrometers wide, and spaced <NUM>-<NUM> micrometers apart. Traces may for example be <NUM> microns thick. This combination of features may advantageously minimize the risk of a failure-inducing fracture across the entire width of any of the electrical traces <NUM>. It is noted that the strain-relieving properties of the aforementioned features are independent of size, and work for devices both larger and smaller than those described herein.

<FIG> is a top schematic view of a curved flex circuit connection portion <NUM> in a flattened (unrolled) state, in accordance with at least one embodiment of the present disclosure. Visible are the scanner portion <NUM> and connection portion <NUM> of the flexible substrate <NUM>. In the example shown in <FIG>, the connection portion <NUM> includes a first bend or curve 1830a and a second bend or curve 1830b that form a dogleg or zig-zag pattern. The connection portion <NUM> also includes a first longitudinal portion 1840a and a second longitudinal portion 1840b. The first and second longitudinal portions 1840a, 1840b are substantially parallel. The curves 1830a, 1830b are configured such that the first and second longitudinal portions 1840a, 1840b extend longitudinally along the flexible elongate member when the flex circuit is wrapped around the cylindrical body and attached to the distal portion of the flexible elongate member of the catheter.

<FIG> is a top schematic view of a curved flex circuit connection portion <NUM> in a flattened (unrolled) state, in accordance with at least one embodiment of the present disclosure. Visible are the scanner portion <NUM> and connection portion <NUM> of the flexible substrate <NUM>. In the example shown in <FIG>, the connection portion <NUM> includes bends <NUM> that form a rounded zig-zag pattern, which may also be referred to as a serpentine pattern.

<FIG> is a schematic diagram of a processor circuit <NUM>, in accordance with aspects of the present disclosure. The processor circuit <NUM> may be implemented in the ultrasound imaging system <NUM>, or other devices or workstations (e.g., third-party workstations, network routers, etc.), or on a cloud processor or other remote processing unit, as necessary to implement the method. 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, or any combination of general-purpose computing devices, reduced instruction set computing (RISC) devices, application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other related logic devices, including mechanical and quantum computers. The processor <NUM> may also comprise 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. 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>, and other processors or devices. 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 ultrasound imaging system <NUM>. The communication module <NUM> may communicate within the processor circuit <NUM> through numerous methods or protocols. Serial communication protocols may include but are not limited to US SPI, I<NUM>C, RS-<NUM>, RS-<NUM>, CAN, Ethernet, ARINC <NUM>, MODBUS, MIL-STD-<NUM>, or any other suitable method or protocol. Parallel protocols include but are not limited to ISA, ATA, SCSI, PCI, IEEE-<NUM>, IEEE-<NUM>, and other suitable protocols. Where appropriate, serial and parallel communications may be bridged by a UART, USART, or other appropriate subsystem.

External communication (including but not limited to software updates, firmware updates, preset sharing between the processor and central server, or readings from the ultrasound device) may be accomplished using any suitable wireless or wired communication technology, such as a cable interface such as a USB, micro USB, Lightning, or FireWire interface, Bluetooth, Wi-Fi, ZigBee, Li-Fi, or cellular data connections such as <NUM>/GSM, <NUM>/UMTS, <NUM>/LTE/WiMax, or <NUM>. For example, a Bluetooth Low Energy (BLE) radio can be used to establish connectivity with a cloud service, for transmission of data, and for receipt of software patches. The controller may be configured to communicate with a remote server, or a local device such as a laptop, tablet, or handheld device, or may include a display capable of showing status variables and other information. Information may also be transferred on physical media such as a USB flash drive or memory stick.

Claim 1:
An intraluminal ultrasound imaging device, comprising:
a flexible elongate member configured to be positioned within a body lumen of a patient; and
an ultrasound imaging assembly coupled to a distal portion of the flexible elongate member and comprising:
a flexible substrate comprising a scanner body portion and an attachment portion extending proximally from the scanner body portion, wherein the attachment portion defines a curved path comprising a first curve curving in a first direction and a second curve curving in a different second direction;
one or more control circuits mounted on the scanner body portion;
one or more transducer elements mounted on the scanner body portion and in communication with the one or more control circuits; and
a plurality of conductive traces disposed on the attachment portion, wherein the plurality of conductive traces is in electrical communication with the one or more control circuits, wherein the plurality of conductive traces follows the curved path of the attachment portion, and
the device being characterized in that
each conductive trace comprises a pattern that bends relative to the curved path of the attachment portion.