WO2025209959A1

WO2025209959A1 - Intravascular imaging and therapeutic treatment of chronic total occlusions and associated systems, devices, and methods

Info

Publication number: WO2025209959A1
Application number: PCT/EP2025/058671
Authority: WO
Inventors: Kellen Scott MOULTON; Sara Rose Chen
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2024-04-02
Filing date: 2025-03-31
Publication date: 2025-10-09
Anticipated expiration: 2026-10-02

Abstract

An apparatus includes a processor circuit that communicates with an intravascular imaging catheter. The processor circuit controls the intravascular imaging catheter to obtain multiple intravascular images of a first blood vessel of vasculature while positioned within the vasculature. The first blood vessel includes a chronic total occlusion (CTO). The processor circuit identifies an anatomical feature associated with the CTO and/or an interventional device for treatment of the CTO in an intravascular image of the multiple intravascular images. The processor circuit outputs, to a display in communication with the processor circuit, a screen display that includes: the intravascular image; and a visual representation associated with the anatomical feature and/or the interventional device. The visual representation provides an indication, to a user, of the identification of the anatomical feature and/or the interventional device in the intravascular image.

Description

INTRAVASCULAR IMAGING AND THERAPEUTIC TREATMENT OF CHRONIC TOTAL OCCLUSIONS AND ASSOCIATED SYSTEMS, DEVICES, AND METHODS.

TECHNICAL FIELD

[0001] The present disclosure relates generally to intravascular imaging (e.g., intravascular ultrasound (IVUS), optical coherence tomography (OCT), etc.) using an intravascular imaging catheter for generating images of a blood vessel. In particular, intravascular imaging of anatomical features and/or interventional devices associated with a chronic total occlusion (CTO) is provided, e.g., to provide user guidance for therapeutic treatment of the CTO.

BACKGROUND

[0002] Intravascular imaging (IVI) (such as intravascular ultrasound (IVUS) or optical coherence tomography (OCT) 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 IVI 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 IVI (e.g., IVUS or OCT) imaging system. The imaging system processes the received ultrasound echoes to produce a cross-sectional image of the vessel where the device is placed.

[0003] Peripheral and coronary vascular procedures, such as stenting, may sometimes be necessary near a bifurcation of one blood vessel from another. When a chronic total occlusion (CTO) occurs near a bifurcation, it is challenging to assess if the interventional devices being used are positioned within the correct blood vessel, or the correct position within one of the blood vessels, after a bifurcation. Thus, locating a chronic total occlusion and imaging the same is challenging.

[0004] The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded as subject matter by which the scope of the disclosure is to be bound. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Illustrative aspects of the present disclosure will be described with reference to the accompanying drawings, of which:

[0008] Figure 1 is a diagrammatic schematic view of an intraluminal imaging system, according to aspects of the present disclosure.

[0009] Figure 2 is a schematic diagram of a processor circuit, according to aspects of the present disclosure.

[0010] Figure 3A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in a main vessel and intravascular imaging catheter in a side branch, according to aspects of the present disclosure.

[0011] Figure 3B is an illustration of a radial and/or tomographic cross-sectional view at a first imaging plane, according to aspects of the present disclosure.

[0012] Figure 3C is an illustration of a radial and/or tomographic cross-sectional view at a second imaging plane, according to aspects of the present disclosure.

[0013] Figure 4A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in a side branch and intravascular imaging catheter in a main vessel, according to aspects of the present disclosure.

[0014] Figure 4B is an illustration of a radial and/or tomographic cross-sectional view at a first imaging plane, according to aspects of the present disclosure.

[0015] Figure 4C is an illustration of a radial and/or tomographic cross-sectional view at a second imaging plane, according to aspects of the present disclosure.

[0016] Figure 5A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in a main vessel, intravascular imaging catheter in a side branch, and a guidewire in the intimal space of the main vessel, according to aspects of the present disclosure.

[0017] Figure 5B is an illustration of a radial and/or tomographic cross-sectional view at an imaging plane including a guidewire in the intimal space of a main vessel, according to aspects of the present disclosure.

[0018] Figure 6A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in a main vessel, intravascular imaging catheter in a

3 side branch, and a guidewire in the subintimal space of the main vessel, according to aspects of the present disclosure.

[0019] Figure 6B is an illustration of a radial and/or tomographic cross-sectional view at an imaging plane including a guidewire in the subintimal space of a main vessel, according to aspects of the present disclosure.

[0020] Figure 7A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in the true lumen of a main vessel and intravascular imaging catheter in the false lumen of a main vessel, according to aspects of the present disclosure.

[0021] Figure 7B is an illustration of a radial and/or tomographic cross-sectional view at an imaging plane including an intravascular imaging catheter in the false lumen of a main vessel, according to aspects of the present disclosure.

[0022] Figure 8A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in the true lumen of a main vessel and intravascular imaging catheter in the true lumen of a main vessel, according to aspects of the present disclosure.

[0023] Figure 8B is an illustration of a radial and/or tomographic cross-sectional view at an imaging plane including a intravascular imaging catheter in the true lumen of a main vessel, according to aspects of the present disclosure.

[0024] Figure 9A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in the true lumen of a main vessel, intravascular imaging catheter in a side branch, and guidewire in the false lumen of a main vessel, according to aspects of the present disclosure.

[0025] Figure 9B is an illustration of a radial and/or tomographic cross-sectional view at an imaging plane including an intravascular imaging catheter in the side branch and a guidewire in the false lumen of a main vessel, according to aspects of the present disclosure.

[0026] Figure 10A is a diagrammatic view of a longitudinal cross-section of a blood vessel including a chronic total occlusion (CTO) in the true lumen of a main vessel, intravascular imaging catheter in a side branch, and guidewire in the true lumen of a main vessel, according to aspects of the present disclosure.

4 [0027] Figure 10B is an illustration of a radial and/or tomographic cross-sectional view at an imaging plane including a intravascular imaging catheter in the side branch and a guidewire in the true lumen of a main vessel, according to aspects of the present disclosure.

[0028] Figure 11 is a diagrammatic schematic view of CTO feature imaging and detection system, according to aspects of the present disclosure.

[0029] Figure 12 is a diagrammatic schematic view of a training system for a machine learning model, according to aspects of the present disclosure.

[0030] Figure 13 is a second diagrammatic schematic view of a training system for a machine learning model, according to aspects of the present disclosure.

[0031] Figure 14 is a diagrammatic schematic of a deep learning network configuration, according to aspects of the present disclosure.

[0032] Figure 15 is an example display of a radial and/or tomographic cross-sectional view and longitudinal view with indicators for proximal cap detection, according to aspects of the present disclosure.

[0033] Figure 16 is an example display of a radial and/or tomographic cross-sectional view, longitudinal view, and x-ray frame with contrast with indicators for proximal cap detection, according to aspects of the present disclosure.

[0034] Figure 17 is an example display of a radial and/or tomographic cross-sectional view and longitudinal view with indicators for guidewire detection and subintimal space detection, according to aspects of the present disclosure.

[0035] Figure 18 is an example display of a radial and/or tomographic cross-sectional view and longitudinal view with indicators for true lumen and false lumen detection, according to aspects of the present disclosure.

[0036] Figure 19 is an example display of a radial and/or tomographic cross-sectional view, longitudinal view, and x-ray frame with contrast with indicators for true lumen and false lumen detection, according to aspects of the present disclosure.

[0037] Figure 20 is an example display of a radial and/or tomographic cross-sectional view and longitudinal view with indicators for guidewire detection and false lumen detection, according to aspects of the present disclosure.

5 DETAILED DESCRIPTION

[0038] When formulating or performing a treatment plan, a physician will often employ intravascular imaging as part of the procedure. For example, imaging may be needed to identify the location of chronic total occlusion (CTO). Furthermore, imaging is important during treatment to ensure the interventional devices are correctly positioned in the vasculature. However, imaging of a CTO can be challenging, and generated images are often hard to interpret.

[0039] The systems, methods, and devices for CTO feature imaging and detection, as described herein, detect features associated with a CTO and generate indicators that make a physician aware of the feature. To detect features a CTO in a blood vessel a model is trained to receive intravascular images, including longitudinal views, and detect features associated with a CTO therein. For example, a model may detect the start of a CTO (i.e., the proximal cap), interventional devices in nearby portions of the vasculature (e.g., a guidewire), intimal and/or subintimal spaces in the vasculature, and true and/or false lumens in the vasculature.

[0040] By automatically detecting CTO features from intravascular imaging treatment planning may be done more quickly and accurately and the progress during a treatment may be accurately evaluated in real-time. For example, a physician may be made aware, informed, and/or alerted that the interventional guidewire has entered a false lumen and thus will not come in to contact with the CTO that is present in the true lumen.

[0041] As used herein, a collection of some or all of the blood vessels in an anatomy may be referred to as vasculature. As used herein, two or more blood vessel connected to one another may indicate any of a number of possible connections, e.g., bifurcation (a side branch splitting off from a main vessel), confluence (two blood vessels combining into one blood vessel or a branch joining another vessel), an extension of one blood vessel from another, etc.

[0042] Examples of calculation or estimation of pullback speed can be found for example in U.S. Application No. 16/542,001, filed August 15, 2019, and U.S. Application No. 16/662,847, filed October 24, 2019, incorporated by reference as though fully set forth herein.

[0043] The devices, systems, and methods described herein can include one or more features described in U.S. Provisional App. No. 63/600,110, filed November 17, 2023, which is hereby incorporated by reference in its entirety as though fully set forth herein.

6 [0044] The devices, systems, and methods described herein can include one or more features described in U.S. Provisional App. No. 62/750,983, filed 26 October 2018, U.S. Provisional App. No. 62/751,268, filed 26 October 2018, U.S. Provisional App. No. 62/751,289, filed 26 October 2018, U.S. Provisional App. No. 62/750,996, filed 26 October 2018, U.S. Provisional App. No. 62/751,167, filed 26 October 2018, and U.S. Provisional App. No. 62/751,185, filed 26 October 2018, each of which is hereby incorporated by reference in its entirety as though fully set forth herein.

[0045] The devices, systems, and methods described herein can also include one or more features described in U.S. Provisional App. No. 62/642,847, filed March 14, 2018, U.S. Provisional App. No. 62/712,009, filed July 30, 2018, U.S. Provisional App. No. 62/711,927, filed July 30, 2018, and U.S. Provisional App. No. 62/643,366, filed March 15, 2018, each of which is hereby incorporated by reference in its entirety as though fully set forth herein.

[0046] These descriptions are provided for exemplary purposes only, and should not be considered to limit the scope of the CTO feature imaging and detection system. Certain features may be added, removed, or modified without departing from the spirit of the claimed subject matter.

[0047] For the purposes of promoting an understanding of the principles of the present disclosure, reference will now be made to the aspects illustrated in the drawings, and specific language will be used to describe the same. It is nevertheless understood that no limitation to the scope of the disclosure is intended. Any alterations and further modifications to the described devices, systems, and methods, and any further application of the principles of the present disclosure are fully contemplated and included within the present disclosure as would normally occur to one skilled in the art to which the disclosure relates. In particular, it is fully contemplated that the features, components, and/or steps described with respect to one aspect may be combined with the features, components, and/or steps described with respect to other aspects of the present disclosure. For the sake of brevity, however, the numerous iterations of these combinations will not be described separately.

[0048] Figure 1 is a diagrammatic schematic view of an intraluminal imaging system, according to aspects of the present disclosure. The intraluminal imaging system 100 can be an intravascular ultrasound (IVUS) imaging system in some aspects. The intraluminal imaging system 100 may include an intraluminal device 102, a patient interface module (PIM) 104, a

7 console or processing system 106, a monitor 108, and an external imaging system 132 which may include angiography, ultrasound, X-ray, computed tomography (CT), magnetic resonance imaging (MRI), or other imaging technologies, equipment, and methods. The intraluminal device 102 is sized and shaped, and/or otherwise structurally arranged to be positioned within a body lumen of a patient. For example, the intraluminal device 102 can be a catheter, guidewire, and/or guide catheter, in various aspects. In some circumstances, the system 100 may include additional elements and/or may be implemented without one or more of the elements illustrated in Figure 1. For example, the system 100 may omit the external imaging system 132.

[0049] The intraluminal imaging system 100 (or intravascular imaging system) can be any type of imaging system suitable for use in the lumens or vasculature of a patient. In some aspects, the intraluminal imaging system 100 is an intravascular ultrasound (IVUS) imaging system. In other aspects, the intraluminal imaging system 100 may include systems configured for forward looking intravascular ultrasound (FL-IVUS) imaging, intravascular photoacoustic (IVPA) imaging, intracardiac echocardiography (ICE), transesophageal echocardiography (TEE), and/or other suitable imaging modalities.

[0050] It is understood that the system 100 and/or device 102 can be configured to obtain any suitable intraluminal imaging data. In some aspects, the device 102 may include an imaging component of any suitable imaging modality, such as optical imaging, optical coherence tomography (OCT), etc. In some aspects, the device 102 may include any suitable non-imaging component, including a pressure sensor, a flow sensor, a temperature sensor, an optical fiber, a reflector, a mirror, a prism, an ablation element, a radio frequency (RF) electrode, a conductor, or combinations thereof. Generally, the device 102 can include an imaging element to obtain intraluminal imaging data associated with the lumen 120. The device 102 may be sized and shaped (and/or configured) for insertion into a vessel or lumen 120 of the patient.

[0051] The system 100 may be deployed in a catheterization laboratory having a control room. The processing system 106 may be located in the control room. Optionally, the processing system 106 may be located elsewhere, such as in the catheterization laboratory itself. The catheterization laboratory may include a sterile field while its associated control room may or may not be sterile depending on the procedure to be performed and/or on the health care facility. The catheterization laboratory and control room may be used to perform any number of medical imaging procedures such as angiography, fluoroscopy, CT, IVUS, virtual histology

8 (VH), forward looking IVUS (FL-IVUS), intraluminal photoacoustic (IVPA) imaging, a fractional flow reserve (FFR) determination, a coronary flow reserve (CFR) determination, optical coherence tomography (OCT), computed tomography, intracardiac echocardiography (ICE), forward-looking ICE (FLICE), intraluminal palpography, transesophageal ultrasound, fluoroscopy, and other medical imaging modalities, or combinations thereof. In some aspects, device 102 may be controlled from a remote location such as the control room, such than an operator is not required to be in close proximity to the patient.

[0052] The intraluminal device 102, PIM 104, monitor 108, and external imaging system 132 may be communicatively coupled directly or indirectly to the processing system 106. These elements may be communicatively coupled to the medical processing system 106 via a wired connection such as a standard copper link or a fiber optic link and/or via wireless connections using IEEE 802.11 Wi-Fi standards, Ultra Wide-Band (UWB) standards, wireless FireWire, wireless USB, or another high-speed wireless networking standard. The processing system 106 may be communicatively coupled to one or more data networks, e.g., a TCP/IP-based local area network (LAN). In other aspects, different protocols may be utilized such as Synchronous Optical Networking (SONET). In some cases, the processing system 106 may be communicatively coupled to a wide area network (WAN). The processing system 106 may utilize network connectivity to access various resources. For example, the processing system 106 may communicate with a Digital Imaging and Communications in Medicine (DICOM) system, a Picture Archiving and Communication System (PACS), and/or a Hospital Information System (HIS) via a network connection.

[0053] At a high level, an ultrasound imaging intraluminal device 102 emits ultrasonic energy from a transducer array 124 included in scanner assembly 110 mounted near a distal end of the intraluminal device 102. The ultrasonic energy is reflected by tissue structures in the medium (such as a lumen 120) surrounding the scanner assembly 110, and the ultrasound echo signals are received by the transducer array 124. The scanner assembly 110 generates electrical signal(s) representative of the ultrasound echoes. The scanner assembly 110 can include one or more single ultrasound transducers and/or a transducer array 124 in any suitable configuration, such as a planar array, a curved array, a circumferential array, an annular array, etc. For example, the scanner assembly 110 can be a one-dimensional array or a two-dimensional array in some instances. In some instances, the scanner assembly 110 can be a rotational ultrasound

9 device. The active area of the scanner assembly 110 can include one or more transducer materials and/or one or more segments of ultrasound elements (e.g., one or more rows, one or more columns, and/or one or more orientations) that can be uniformly or independently controlled and activated. The active area of the scanner assembly 110 can be patterned or structured in various basic or complex geometries. The scanner assembly 110 can be disposed in a side-looking orientation (e.g., ultrasonic energy emitted perpendicular and/or orthogonal to the longitudinal axis of the intraluminal device 102) and/or a forward-looking looking orientation (e.g., ultrasonic energy emitted parallel to and/or along the longitudinal axis). In some instances, the scanner assembly 110 is structurally arranged to emit and/or receive ultrasonic energy at an oblique angle relative to the longitudinal axis, in a proximal or distal direction. In some aspects, ultrasonic energy emission can be electronically steered by selective triggering of one or more transducer elements of the scanner assembly 110.

[0054] The ultrasound transducer(s) of the scanner assembly 110 can be a piezoelectric micromachined ultrasound transducer (PMUT), capacitive micromachined ultrasonic transducer (CMUT), single crystal, lead zirconate titanate (PZT), PZT composite, other suitable transducer type, and/or combinations thereof. In an aspect the ultrasound transducer array 124 can include any suitable number of individual transducer elements or acoustic elements between 1 acoustic element and 1000 acoustic elements, including values such as 2 acoustic elements, 4 acoustic elements, 36 acoustic elements, 64 acoustic elements, 128 acoustic elements, 500 acoustic elements, 812 acoustic elements, and/or other values both larger and smaller.

[0055] The PIM 104 transfers the received echo signals to the processing system 106 where the ultrasound image (including the flow information) is reconstructed and displayed on the monitor 108. The console or processing system 106 can include a processor and a memory. The processing system 106 may be operable to facilitate the features of the intraluminal imaging system 100 described herein. For example, the processor can execute computer readable instructions stored on the non-transitory tangible computer readable medium.

[0056] The PIM 104 facilitates communication of signals between the processing system 106 and the scanner assembly 110 included in the intraluminal device 102. This communication may include providing commands to integrated circuit controller chip(s) within the intraluminal device 102, selecting particular element(s) on the transducer array 124 to be used for transmit and receive, providing the transmit trigger signals to the integrated circuit controller chip(s) to

10 activate the transmitter circuitry to generate an electrical pulse to excite the selected transducer array element(s), and/or accepting amplified echo signals received from the selected transducer array element(s) via amplifiers included on the integrated circuit controller chip(s). In some aspects, the PIM 104 performs preliminary processing of the echo data prior to relaying the data to the processing system 106. In examples of such aspects, the PIM 104 performs amplification, filtering, and/or aggregating of the data. In an aspect, the PIM 104 also supplies high- and low- voltage DC power to support operation of the intraluminal device 102 including circuitry within the scanner assembly 110.

[0057] The processing system 106 receives echo data from the scanner assembly 110 by way of the PIM 104 and processes the data to reconstruct an image of the tissue structures in the medium surrounding the scanner assembly 110. Generally, the device 102 can be utilized within any suitable anatomy and/or body lumen of the patient. The processing system 106 outputs image data such that an image of the vessel or lumen 120, such as a cross-sectional IVUS image of the lumen 120, is displayed on the monitor 108. Lumen 120 may represent fluid filled or fluid-surrounded structures, both natural and man-made. Lumen 120 may be within a body of a patient. Lumen 120 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 102 may be used to examine any number of anatomical locations and tissue types, including without limitation, organs including the liver, heart, kidneys, gall bladder, pancreas, lungs; ducts; intestines; nervous system structures including the brain, dural sac, spinal cord and peripheral nerves; the urinary tract; as well as valves within the blood, chambers or other parts of the heart, and/or other systems of the body. In addition to natural structures, the device 102 may be used to examine man-made structures such as, but without limitation, heart valves, stents, shunts, filters and other devices.

[0058] The controller or processing system 106 may include a processing circuit having one or more processors in communication with memory and/or other suitable tangible computer readable storage media. The controller or processing system 106 may be configured to carry out one or more aspects of the present disclosure. In some aspects, the processing system 106 and the monitor 108 are separate components. In other aspects, the processing system 106 and the monitor 108 are integrated in a single component. For example, the system 100 can include a

11 touch screen device, including a housing having a touch screen display and a processor. The system 100 can include any suitable input device, such as a touch sensitive pad or touch screen display, keyboard/mouse, joystick, button, etc., for a user to select options shown on the monitor 108. The processing system 106, the monitor 108, the input device, and/or combinations thereof can be referenced as a controller of the system 100. The controller can be in communication with the device 102, the PIM 104, the processing system 106, the monitor 108, the input device, and/or other components of the system 100.

[0059] In some aspects, the intraluminal device 102 includes some features similar to traditional solid-state IVUS catheters, such those disclosed in U.S. Patent No. 7,846,101, which is incorporated by reference herein in its entirety. For example, the intraluminal device 102 may include the scanner assembly 110 near a distal end of the intraluminal device 102 and a transmission line bundle 112 extending along the longitudinal body of the intraluminal device 102. The cable or transmission line bundle 112 can include a plurality of conductors, including one, two, three, four, five, six, seven, or more conductors.

[0060] The transmission line bundle 112 terminates in a PIM connector 114 at a proximal end of the intraluminal device 102. The PIM connector 114 electrically couples the transmission line bundle 112 to the PIM 104 and physically couples the intraluminal device 102 to the PIM 104. In an aspect, the intraluminal device 102 further includes a guidewire exit port 116.

Accordingly, in some instances the intraluminal device 102 is a rapid-exchange catheter. The guidewire exit port 116 allows a guidewire 118 to be inserted towards the distal end in order to direct the intraluminal device 102 through the lumen 120.

[0061] The monitor 108 may be a display device such as a computer monitor or other type of screen. The monitor 108 may be used to display selectable prompts, instructions, and visualizations of imaging data to a user. In some aspects, the monitor 108 may be used to provide a procedure-specific workflow to a user to complete an intraluminal imaging procedure. This workflow may include performing a pre-stent plan to determine the state of a lumen and potential for a stent, as well as a post-stent inspection to determine the status of a stent that has been positioned in a lumen.

[0062] The external imaging system 132 can be configured to obtain x-ray, radiographic, angiographic/venographic (e.g., with contrast), and/or fluoroscopic (e.g., without contrast) images of the body of a patient (including the vessel 120). External imaging system 132 may

12 also be configured to obtain computed tomography images of the body of the patient (including the vessel 120). The external imaging system 132 may include an external ultrasound probe configured to obtain ultrasound images of the body of the patient (including the vessel 120) while positioned outside the body. In some aspects, the system 100 includes other imaging modality systems (e.g., MRI) to obtain images of the body of the patient (including the vessel 120). The processing system 106 can utilize the images of the body of the patient in conjunction with the intraluminal images obtained by the intraluminal device 102.

[0063] Figure 2 is a schematic diagram of a processor circuit 250, according to aspects of the present disclosure. The processor circuit 250 may be implemented in the intraluminal imaging system 100, 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 250 may include a processor 260, a memory 264, and a communication module 268. These elements may be in direct or indirect communication with each other, for example via one or more buses.

[0064] The processor 260 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 260 may also comprise another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor 260 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0065] The memory 264 may include a cache memory (e.g., a cache memory of the processor 260), 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 aspect, the memory 264 includes a non-transitory computer-readable medium. The memory 264 may store instructions 266. The

13 instructions 266 may include instructions that, when executed by the processor 260, cause the processor 260 to perform the operations described herein. Instructions 266 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.

[0066] The communication module 268 can include any electronic circuitry and/or logic circuitry to facilitate direct or indirect communication of data between the processor circuit 250, and other processors or devices. In that regard, the communication module 268 can be an input/output (I/O) device. In some instances, the communication module 268 facilitates direct or indirect communication between various elements of the processor circuit 250 and/or the intraluminal imaging system 100. The communication module 268 may communicate within the processor circuit 250 through numerous methods or protocols. Serial communication protocols may include but are not limited to United States Serial Protocol Interface (US SPI), Inter- Integrated Circuit (I²C), Recommended Standard 232 (RS-232), RS-485, Controller Area Network (CAN), Ethernet, Aeronautical Radio, Incorporated 429 (ARINC 429), MODBUS, Military Standard 1553 (MIL-STD-1553), or any other suitable method or protocol. Parallel protocols include but are not limited to Industry Standard Architecture (ISA), Advanced Technology Attachment (ATA), Small Computer System Interface (SCSI), Peripheral Component Interconnect (PCI), Institute of Electrical and Electronics Engineers 488 (IEEE-488), IEEE- 1284, and other suitable protocols. Where appropriate, serial and parallel communications may be bridged by a Universal Asynchronous Receiver Transmitter (UART), Universal Synchronous Receiver Transmitter (US ART), or other appropriate subsystem.

[0067] External communication (including but not limited to software updates, firmware updates, preset sharing between the processor and central server, or readings from the annular ultrasound imaging array) may be accomplished using any suitable wireless or wired communication technology, such as a cable interface such as a universal serial bus (USB), micro USB, Lightning, or FireWire interface, Bluetooth, Wi-Fi, ZigBee, Li-Fi, or cellular data connections such as 2G/GSM (global system for mobiles) , 3G/UMTS (universal mobile telecommunications system), 4G, long term evolution (LTE), WiMax, or 5G. For example, a

14 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.

[0068] It will also be understood that one or more of the steps of the methods described above can be performed by one or more components of an ultrasound imaging system, such as the processing system, a multiplexer, a beamformer, a signal processing unit, an image processing unit, or any other suitable component of the system. For example, activating the scan sequences may be carried out by a processor in communication with a multiplexer configured to select or activate one or more elements of an ultrasound transducer array. In some aspects, generating the ultrasound images may include beamforming incoming signals from the ultrasound imaging device and processing the beamformed signals by an image processor. The processing components of the system can be integrated within the ultrasound imaging device, contained within an external console, or may be a separate component.

[0069] Figure 3A is a diagrammatic view of a longitudinal cross-section of a blood vessel 300 including a chronic total occlusion (CTO) 320 in a main vessel 304 and intravascular imaging catheter 330 in a side branch 302, according to aspects of the present disclosure. The wall of the blood vessel 300 may comprise three layers: an intima 310, a media 312, and an adventitia 314. The intima 310, media 312, and adventitia 314 may collectively be referred to as the vessel wall. The blood vessel 300 includes a main vessel 304 and side branch 302. Blood may be flowing in a direction 325 down the blood vessel 300. As depicted in Fig. 3A, a CTO 320 is present in the main vessel 304. A CTO may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. A stiffer guidewire may be used when an initial softer guidewire is unable to penetrate the CTO 320. The CTO 320 includes a proximal cap 322. The proximal cap 322 is the surface marking the beginning of the CTO 320. Because of the CTO 320 blocking the main vessel 304, blood flow through the blood vessel 300 is restricted to the side branch 302.

[0070] An intravascular imaging catheter 330 may be present within the blood vessel 300. In some instances, the intravascular imaging catheter 330 may comprise a portion of an intraluminal

15 imaging device 100, as described in Fig. 1. The intravascular imaging catheter 330 is partially positioned within the side branch 302. For sake of explanation the intravascular imaging catheter 330 is depicted in a first position to generate an image from a first imaging plane 332 and a second position to generate an image from a second imaging plane 334. The cross-section view/image associated with the first imaging plane 332 and second imaging plane 334 are depicted in Figs. 3B and 3C, respectively.

[0071] Figure 3B is an illustration of a radial and/or tomographic cross-sectional view 340 at a first imaging plane 332, according to aspects of the present disclosure. Cross-sectional view 340 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 330. The location of the intravascular imaging catheter 330 is covered by a mask 345 overlayed on the cross-sectional view 340. The layers 310, 312, 314 of the vessel wall are visible for both the side branch 302 and main vessel 304. As shown in Fig. 3A, the first imaging plane crosses the side branch 302 and main vessel 304 near the bifurcation point. Thus, the lumens associated with the side branch 302 and main vessel 304 are near to each other in the cross-sectional view 340. Additionally, the first imaging plane 332 intersects the proximal cap 322, resulting in the cross-sectional view 340 that shows the proximal cap 322 as a boundary between CTO 320 and a region that would be filled with blood.

[0072] Figure 3C is an illustration of a radial and/or tomographic cross-sectional view 350 at a second imaging plane 334, according to aspects of the present disclosure. Cross-sectional view 350 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 330. The location of the intravascular imaging catheter 330 is covered by a mask 355 overlayed on the cross-sectional view 350. The layers 310, 312, 314 of the vessel wall are visible for both the side branch 302 and main vessel 304. As shown in Fig. 3A, the second imaging plane crosses the side branch 302 and main vessel 304 farther from the bifurcation point than the first imaging plane 332. Thus, the lumens associated with the side branch 302 and main vessel 304 are spaced farther from each other in the cross-sectional view 350. Additionally, the second imaging plane 334 intersects the CTO 320, resulting in the cross- sectional view 350 that shows the CTO 320 completely filling the main branch 304.

[0073] Figure 4A is a diagrammatic view of a longitudinal cross-section of a blood vessel 400 including a chronic total occlusion (CTO) 420 in a side branch 402 and intravascular imaging catheter 430 in a main vessel 404, according to aspects of the present disclosure. The

16 wall of the blood vessel 400 may comprise three layers: an intima 410, a media 412, and an adventitia 414. The intima 410, media 412, and adventitia 414 may collectively be referred to as the vessel wall. The blood vessel 400 includes a main vessel 404 and side branch 402. Blood may be flowing in a direction 425 down the blood vessel 400. A CTO 420 is present at the confluence (also referred to as the “bifurcation”) of a side branch 402 and main vessel 404 and partially extends into the side branch 402 and main branch 404. A CTO may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. The CTO 420 includes a proximal cap 422. The proximal cap 422 is the surface marking the beginning of the CTO 420. Because of the CTO 420 blocking the side branch 402, blood flow through the blood vessel 400 is restricted to the main vessel 404.

[0074] An intravascular imaging catheter 430 may be present within the blood vessel 400. In some instances, the intravascular imaging catheter 430 may comprise a portion of an intraluminal imaging device 100, as described in Fig. 1. As depicted in Fig. 4A, the intravascular imaging catheter 430 is positioned within the main vessel 404. For sake of explanation the intravascular imaging catheter 430 is depicted in a first position to generate an image from a first imaging plane 432 and a second position to generate an image from a second imaging plane 434. The cross-section view/image associated with the first imaging plane 432 and second imaging plane 434 are depicted in Figs. 4B and 4C, respectively.

[0075] Figure 4B is an illustration of a radial and/or tomographic cross-sectional view 440 at a first imaging plane 432, according to aspects of the present disclosure. Cross-sectional view 440 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 430. The location of the intravascular imaging catheter 430 is covered by a mask 445 overlayed on the cross-sectional view 440. The layers 410, 412, 414 of the vessel wall are visible for both the start of the side branch 402 and main vessel 404. As shown in Fig. 4A, the first imaging plane 432 crosses at or near the bifurcation of the side branch 402 and main vessel 404. Thus, a single lumen is associated with the side branch 402 and main vessel 404 in the cross-sectional view 440, though lumen has an irregular shape similar to two circles flattened on one side and fused together. Additionally, the first imaging plane 432 intersects the proximal cap 422, resulting in the cross-sectional view 440 that shows the proximal cap 422 as a boundary between CTO 420 and a region filled with blood (e.g., the blood flowing down the main vessel 404).

17 [0076] Figure 4C is an illustration of a radial and/or tomographic cross-sectional view 450 at a second imaging plane 434, according to aspects of the present disclosure. Cross-sectional view 450 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 430. The location of the intravascular imaging catheter 430 is covered by a mask 455 overlayed on the cross-sectional view 450. The layers 410, 412, 414 of the vessel wall are visible for both the side branch 402 and main vessel 404. As shown in Fig. 4A, the second imaging plane 434 crosses the side branch 402 and main vessel 404 after the bifurcation. Thus, the lumens associated with the side branch 402 and main vessel 404 shows the separation between the side branch 402 and main vessel 404 within the second imaging plane 434 in the cross-sectional view 450. Additionally, the second imaging plane 434 intersects the CTO 420, resulting in the cross-sectional view 450 that shows the CTO 320 completely filling the side branch 402.

[0077] Figure 5A is a diagrammatic view of a longitudinal cross-section of a blood vessel 500 including a chronic total occlusion (CTO) 520 in a main vessel 504, intravascular imaging catheter 530 in a side branch 502, and a guidewire 535 in the intimal space 505 of the main vessel 504, according to aspects of the present disclosure. The wall of the blood vessel 500 may comprise three layers: an intima 510, a media 512, and an adventitia 514. The intima 510, media 512, and adventitia 514 may collectively be referred to as the vessel wall. The blood vessel 500 includes a main vessel 504 and side branch 502. The space radially inward (i.e., towards the center of the vessel) from the intima 510 of the main vessel 504 may be referred to as the intimal space 505 of the main vessel 504. When no false lumen is present, the intimal space 505 is equivalent to the lumen of the main vessel 504. Blood may be flowing in a direction 525 down the blood vessel 500. A CTO 520 is present in the main vessel 504. The CTO 520 may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. The CTO 520 includes a proximal cap 522. The proximal cap 522 is the surface marking the beginning of the CTO 520. Because of the CTO 520 blocking the main vessel 504, blood flow through the blood vessel 500 is restricted to the side branch 502.

[0078] An intravascular imaging catheter 530 and a guidewire 535 may be present within the blood vessel 500. In some instances, the intravascular imaging catheter 530 may comprise a portion of an intraluminal imaging device 100, as described in Fig. 1. In some embodiments, guidewire 535 may be interventional guidewire or a microcatheter. Guidewire 535 may have

18 various stiffnesses, wherein stiffer wires may be used if the composition of the CTO 520 is less soft (e.g., fibro-fatty versus fatty plaque). A stiffer guidewire may be used when an initial softer guidewire is unable to penetrate the CTO 520. Guidewire may be used to penetrate the CTO 520 as a part of a therapeutic procedure, e.g., balloon angioplasty.

[0079] The intravascular imaging catheter 530 is positioned within the side branch 502. The intravascular imaging catheter 530 is depicted in a first position to generate an image associated with imaging plane 532. Intravascular imaging catheter 530 may be used to determine the location of the guidewire 535 within the main vessel 504. As depicted, the guidewire 535 is within the intimal space 505 of the main vessel 504. Because the imaging plane 532 of the intravascular imaging catheter 530 intersects the guidewire 535, the guidewire 535 should appear in the cross-sectional image (Fig. 5B) associated with the imaging plane 532. In some instances, a therapeutic procedure may intend for the guidewire 535 to be near the radial center in the main vessel 504. In that case, guidewire 535 may not be optimally placed as it is off center. Alternatively, some therapeutic procedures may intend for a guidewire 535 to traverse a blood vessel through a subintimal space that is located radially outward from the intima 510. In that case, guidewire 535 has not be positioned as intended; it is still in the intimal space 505. The cross-sectional view/image associated with the imaging plane is depicted in Fig. 5B.

[0080] Figure 5B is an illustration of a radial and/or tomographic cross-sectional view 540 at an imaging plane 532 including a guidewire 535 in the intimal space 505 of a main vessel 504, according to aspects of the present disclosure. Cross-sectional view 540 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 530. The location of the intravascular imaging catheter 530 is covered by a mask 545 overlayed on the cross-sectional view 540. The layers 510, 512, 514 of the vessel wall are visible for both the side branch 502 and main vessel 504. As shown in Fig. 5A, the imaging plane 532 crosses both the side branch 502 and main vessel 504. Thus, the lumens associated with the side branch 502 and main vessel 504 are present in the cross-sectional view 540. Additionally, the imaging plane 532 intersects the CTO 520, resulting in the cross-sectional view 540 showing the lumen/intimal space of the main vessel 504 filled by CTO 520.

[0081] Cross-sectional view 540 shows the location of the guidewire 535 in the intimal space 505 of the main vessel 504. The cross-sectional view may be useful for determining the location of the guidewire 535 and detecting if it is within the intimal or subintimal space. Some

19 therapeutic procedures may require a guidewire 535 be centered in the main vessel 504, while others may require the guidewire 535 traverse the vessel in a subintimal space. When there is such a requirement for guidewire location, the cross-sectional view may be beneficial to a physician performing the procedure. As depicted, guidewire 535 may be sufficiently, though not optimally, placed to satisfy therapeutic procedures requiring centering of the guidewire 535. However, guidewire 535 is likely insufficiently placed to satisfy therapeutic procedures that require the guidewire 535 to traverse the subintimal space.

[0082] Figure 6A is a diagrammatic view of a longitudinal cross-section of a blood vessel 600 including a chronic total occlusion (CTO) 620 in a main vessel 604, intravascular imaging catheter 630 in a side branch 602, and a guidewire 635 in the subintimal space 607 of the main vessel 604, according to aspects of the present disclosure. The wall of the blood vessel 600 may comprise three layers: an intima 610, a media 612, and an adventitia 614. The intima 610, media 612, and adventitia 614 may collectively be referred to as the vessel wall. The blood vessel 600 includes a main vessel 604 and side branch 602. The space radially outward (i.e., away from the center of the vessel) from the intima 610 of the main vessel 604 may be referred to as the subintimal space 607 of the main vessel 604. When no false lumen is present, the intimal space 505 is equivalent to the lumen of the main vessel 504. Blood may be flowing in a direction 625 down the blood vessel 600. A CTO 620 is present in the main vessel 604. The CTO 620 may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. The CTO 620 includes a proximal cap 622. The proximal cap 622 is the surface marking the beginning of the CTO 620. Because of the CTO 620 blocking the main vessel 604, blood flow through the blood vessel 600 is restricted to the side branch 602.

[0083] An intravascular imaging catheter 630 and a guidewire 635 may be present within the blood vessel 600. In some instances, the intravascular imaging catheter 630 may comprise a portion of an intraluminal imaging device 100, as described in Fig. 1. In some embodiments, intravascular device 635 may be an interventional/crossing guidewire, a guide catheter, a microcatheter, etc. Guidewire 635 may have various stiffnesses, wherein stiffer wires may be used if the composition of the CTO 620 is less soft (e.g., fibro-fatty versus fatty plaque). A stiffer guidewire may be used when an initial softer guidewire is unable to penetrate the CTO 620. As a part of a therapeutic procedure, e.g., balloon angioplasty, a guidewire may be intended to penetrate the CTO 620.

20 [0084] The intravascular imaging catheter 630 is positioned within the side branch 602. The intravascular imaging catheter 630 is depicted in a first position to generate an image associated with an imaging plane 632. Intravascular imaging catheter 630 may be used to determine the location of the guidewire 635 within the main vessel 604. As depicted, the guidewire 635 enters the subintimal space 607 in the main vessel 604. Because the imaging plane 632 of the intravascular imaging catheter 630 intersects the guidewire 635 where it is in the subintimal space 607, it should appear in the cross-sectional image (Fig. 6B) associated with the imaging plane 632. In some instances, a therapeutic procedure may intend for the guidewire 635 to be near the radial center in the main vessel 604. In that case, guidewire 635 has deviated from the intended path. Alternatively, some therapeutic procedures may intend for a guidewire 635 to traverse a blood vessel through the subintimal space 607. In that case, guidewire 635 has successfully crossed into the subintimal space 607. The cross-section view/image associated with the imaging plane is depicted in Fig. 6B.

[0085] Figure 6B is an illustration of a radial and/or tomographic cross-sectional view 640 at an imaging plane 632 including a guidewire 635 in the subintimal space 607 of a main vessel 604, according to aspects of the present disclosure. Cross-sectional view 640 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 630. The location of the intravascular imaging catheter 630 is covered by a mask 645 overlayed on the cross-sectional view 640. The layers 610, 612, 614 of the vessel wall are visible for both the side branch 602 and main vessel 604. As shown in Fig. 6A, the imaging plane 632 crosses both the side branch 602 and main vessel 604. Thus, the lumens associated with the side branch 602 and main vessel 604 are present in the cross-sectional view 640. Additionally, the imaging plane 632 intersects the CTO 620, resulting in the cross-sectional view 640 showing the lumen/intimal space of the main vessel 604 filled by CTO 620.

[0086] Cross-sectional view 640 shows the location of the guidewire 635 in the subintimal space 607 of the main vessel 604. The cross-sectional view 640 may be useful for determining the location of the guidewire 635 and detecting if it is within the intimal or subintimal space. Some therapeutic procedures may require a guidewire 635 be centered in the main vessel 604, while others may require the guidewire 635 traverse the vessel in a subintimal space. When there is such a requirement for guidewire location, the cross-sectional view may be beneficial to a physician performing the procedure. As depicted, guidewire 635 fails satisfy therapeutic

21 procedures requiring centering of the guidewire 635. However, guidewire 635 likely satisfies therapeutic procedures that require the guidewire 535 to traverse the subintimal space.

[0087] Figure 7A is a diagrammatic view of a longitudinal cross-section of a blood vessel 700 including a chronic total occlusion (CTO) 720 in the true lumen 705 of a main vessel 704 and intravascular imaging catheter 730 in the false lumen 707 of a main vessel 704, according to aspects of the present disclosure. The wall of the blood vessel 700 may comprise three layers: an intima 710, a media 712, and an adventitia 714. The intima 710, media 712, and adventitia 714 may collectively be referred to as the vessel wall. The blood vessel 700 includes a main vessel 704 and side branch 702. Main vessel 704 includes a true lumen 705 and false lumen 707. The true lumen refers to the space surrounded by the intima 710, while the false lumen 707 refers to a subintimal space in which blood is present. Blood may be flowing in a direction 725 through the blood vessel 700.

[0088] A CTO 720 is present in the true lumen 705 of the main vessel 704. A CTO may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. The CTO 720 includes a proximal cap 722. The proximal cap 722 is the surface marking the beginning of the CTO 720. Because of the CTO 720 blocking the true lumen 705 of the main vessel 704, blood flows through the side branch 702 and through and/or into the false lumen 707.

[0089] An intravascular imaging catheter 730 may be present within the blood vessel 700. In some instances, the intravascular imaging catheter 730 may comprise a portion of an intraluminal imaging device 100, as described in Fig. 1. The intravascular imaging catheter 730 is partially positioned within the false lumen 707 of the main branch 704. The intravascular imaging catheter 730 is depicted in a first position to generate an image associated with an imaging plane 732. Though the sensing portion of the intravascular imaging catheter 730 may be within the false lumen 707, the catheter 730 can image each of the vessel structures intersecting the imaging plane 732, including the side branch 702 and the true lumen 705 of the main vessel 704. The cross-section view/image associated with the imaging plane 732 is depicted in Fig. 7B.

[0090] Figure 7B is an illustration of a radial and/or tomographic cross-sectional view 740 at an imaging plane 732 including an intravascular imaging catheter 730 in the false lumen 707 of a main vessel 704, according to aspects of the present disclosure. Cross-sectional view 740 may be an intravascular image generated from intravascular image data gathered by the intravascular

22 imaging catheter 730. The location of the intravascular imaging catheter 730 is covered by a mask 745 overlayed on the cross-sectional view 740. The layers 710,712, 714 of the vessel wall are visible for both the side branch 702 and main vessel 704. As shown in Fig. 7A, the imaging plane 732 crosses both the side branch 702 and main vessel 704. Thus, the lumens associated with the side branch 702 and main vessel 704 are present in the cross-sectional view 740. Furthermore, the imaging plane 732 cross the true lumen 705 and false lumen 707 of the main vessel 704. As depicted in Fig. 7B, the false lumen 707 has the shape of a crescent and the true lumen 705 has the shape of a circle. The catheter 730 is in the false lumen 707 at the location of the mask 745.

[0091] Figure 8A is a diagrammatic view of a longitudinal cross-section of a blood vessel 800 including a chronic total occlusion (CTO) 820 in the true lumen 805 of a main vessel 804 and intravascular imaging catheter 830 in the true lumen 805 of a main vessel 804, according to aspects of the present disclosure. The wall of the blood vessel 800 may comprise three layers: an intima 810, a media 812, and an adventitia 814. The intima 810, media 812, and adventitia 814 may collectively be referred to as the vessel wall. The blood vessel 800 includes a main vessel 804 and side branch 802. Main vessel 804 includes a true lumen 805 and false lumen 807. The true lumen refers to the space surrounded by the intima 810, while the false lumen 807 refers to a subintimal space in which blood is present. Blood may be flowing in a direction 825 through the blood vessel 800.

[0092] A CTO 820 is present in the true lumen 805 of the main vessel 804. A CTO may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. The CTO 820 includes a proximal cap 822. The proximal cap 822 is the surface marking the beginning of the CTO 820. Because of the CTO 820 blocking the true lumen 805 of the main vessel 804, blood flows through the side branch 802 and through and/or into the false lumen 807.

[0093] An intravascular imaging catheter 830 may be present within the blood vessel 800. In some instances, the intravascular imaging catheter 830 may comprise a portion of an intraluminal imaging device 100, as described in Fig. 1. The intravascular imaging catheter 830 is partially positioned within the true lumen 805 of the main branch 804. The intravascular imaging catheter 830 is depicted in a first position to generate an image associated with an imaging plane 832. Though the sensing portion of the intravascular imaging catheter 830 may be within the true

23 lumen 805, the catheter 830 can image each of the vessel structures intersecting the imaging plane 832, including the side branch 802 and the false lumen 807 of the main vessel 804. The cross-section view/image associated with the imaging plane 832 is depicted in Fig. 8B.

[0094] Figure 8B is an illustration of a radial and/or tomographic cross-sectional view 840 at an imaging plane 832 including a intravascular imaging catheter 830 in the true lumen 805 of a main vessel 804, according to aspects of the present disclosure. Cross-sectional view 840 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 830. The location of the intravascular imaging catheter 830 is covered by a mask 845 overlayed on the cross-sectional view 840. The layers 810,812, 814 of the vessel wall are visible for both the side branch 802 and main vessel 804. As shown in Fig. 8A, the imaging plane 832 crosses both the side branch 802 and main vessel 804. Thus, the lumens associated with the side branch 802 and main vessel 804 are present in the cross-sectional view 840. Furthermore, the imaging plane 832 cross the true lumen 805 and false lumen 807 of the main vessel 804. As depicted in Fig. 8B, the false lumen 807 has the shape of a crescent and the true lumen 805 has the shape of a circle. The catheter 830 is in the true lumen 805 at the location of the mask 845.

[0095] Figure 9A is a diagrammatic view of a longitudinal cross-section of a blood vessel 900 including a chronic total occlusion (CTO) 920 in the true lumen 905 of a main vessel 904, intravascular imaging catheter 930 in a side branch 902, and guidewire 935 in the false lumen 907 of a main vessel 804, according to aspects of the present disclosure. The wall of the blood vessel 900 may comprise three layers: an intima 910, a media 912, and an adventitia 914. The intima 910, media 912, and adventitia 914 may collectively be referred to as the vessel wall. The blood vessel 900 includes a main vessel 904 and side branch 902. Main vessel 904 includes a true lumen 905 and false lumen 907. The true lumen refers to the space surrounded by the intima 910, while the false lumen 907 refers to a subintimal space in which blood is present. Blood may be flowing in a direction 925 through the blood vessel 900.

[0096] A CTO 920 is present in the true lumen 905 of the main vessel 904. A CTO may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. The CTO 920 includes a proximal cap 922. The proximal cap 922 is the surface marking the beginning of the CTO 920. Because of the CTO 920 blocking the

24 true lumen 905 of the main vessel 904, blood flows through the side branch 902 and through and/or into the false lumen 907.

[0097] An intravascular imaging catheter 930 and a guidewire 935 may be present within the blood vessel 900. In some instances, the intravascular imaging catheter 930 may comprise a portion of an intraluminal imaging device 100, as described in Fig. 1. In some embodiments, guidewire 935 may be an interventional guidewire or a microcatheter. Guidewire 935 may have various stiffnesses, wherein stiffer wires may be used if the composition of the CTO 920 is less soft (e.g., fibro-fatty versus fatty plaque). A stiffer guidewire may be used when an initial softer guidewire is unable to penetrate the CTO 920. As a part of a therapeutic procedure, e.g., balloon angioplasty, a guidewire may be intended to penetrate the CTO 920.

[0098] The intravascular imaging catheter 930 is positioned within the side branch 902. The intravascular imaging catheter 930 is depicted in a first position to generate an image associated with an imaging plane 932. Intravascular imaging catheter 930 may be used to determine the location of the guidewire 935 within the main vessel 904. As depicted, the guidewire 935 enters the false lumen 907 of the main vessel 904. Because the imaging plane 932 of the intravascular imaging catheter 930 intersects the guidewire 935 in the false lumen 907, it should appear in the cross-sectional image (Fig. 9B) associated with the imaging plane 932. In some instances, a therapeutic procedure may intend for the guidewire 935 to be near the radial center in the true lumen 905 of the main vessel 904. In that case, guidewire 935 has deviated from the intended path. Alternatively, some therapeutic procedures may intend for a guidewire 935 to traverse a blood vessel through the false lumen 907. In that case, guidewire 635 has been successfully positioned in the false lumen 907. The cross-section view/image associated with the imaging plane is depicted in Fig. 9B.

[0099] Figure 9B is an illustration of a radial and/or tomographic cross-sectional view 940 at an imaging plane 932 including an intravascular imaging catheter 930 in the side branch 902 and a guidewire 935 in the false lumen 907 of a main vessel 904, according to aspects of the present disclosure. Cross-sectional view 940 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 930. The location of the intravascular imaging catheter 930 is covered by a mask 945 overlayed on the cross-sectional view 940. The layers 910, 912, 914 of the vessel wall are visible for both the side branch 902 and main vessel 904. As shown in Fig. 9A, the imaging plane 932 crosses both the side branch 902 and main

25 vessel 904. Thus, the lumens associated with the side branch 902 and main vessel 904 are present in the cross-sectional view 940. Furthermore, the imaging plane 932 crosses the true lumen 905 and false lumen 907 of the main vessel 904. The false lumen 907 has the shape of a crescent and the true lumen 905 has the shape of a circle. The catheter 930 is in the false lumen 907 at the location of the mask 945.

[0100] Cross-sectional view 940 shows the location of the guidewire 935 in the false lumen 907 of the main vessel 904. The cross-sectional view 940 may be useful for determining the location of the guidewire 935 and detecting if it is within the true lumen 905 or false lumen 907. Some therapeutic procedures may intend a guidewire 935 be centered in the true lumen 905 of the main vessel 904, while others may intend for the guidewire 935 to be positioned in the false lumen 907. When there is such a requirement for guidewire location, the cross-sectional view 940 may be beneficial to a physician performing the procedure. As depicted, guidewire 935 fails satisfy therapeutic procedures requiring centering of the guidewire 935 in the true lumen 905. However, guidewire 935 does satisfy therapeutic procedures that require the guidewire 935 to be positioned in the false lumen 907.

[0101] Figure 10A is a diagrammatic view of a longitudinal cross-section of a blood vessel 1000 including a chronic total occlusion (CTO) 1020 in the true lumen 1005 of a main vessel 1004, intravascular imaging catheter 1030 in a side branch 1002, and guidewire 1035 in the true lumen 1005 of a main vessel 1004, according to aspects of the present disclosure. The wall of the blood vessel 1000 may comprise three layers: an intima 1010, a media 1012, and an adventitia 1014. The intima 1010, media 1012, and adventitia 1014 may collectively be referred to as the vessel wall. The blood vessel 1000 includes a main vessel 1004 and side branch 1002. Main vessel 1004 includes a true lumen 1005 and false lumen 1007. The true lumen refers to the space surrounded by the intima 1010, while the false lumen 1007 refers to a subintimal space in which blood is present. Blood may be flowing in a direction 1025 through the blood vessel 1000.

[0102] A CTO 1020 is present in the true lumen 1005 of the main vessel 1004. A CTO may comprise one or more plaques of varying composition and/or hardness, e.g., fatty, fibro-fatty, dense calcium, necrotic core, etc. The CTO 1020 includes a proximal cap 1022. The proximal cap 1022 is the surface marking the beginning of the CTO 1020. Because of the CTO 1020 blocking the true lumen 1005 of the main vessel 1004, blood flows through the side branch 1002 and through and/or into the false lumen 1007.

26 [0103] An intravascular imaging catheter 1030 and a guidewire 1035 may be present within the blood vessel 1000. In some instances, the intravascular imaging catheter 1030 may comprise a portion of an intraluminal imaging device 100, as described in Fig. 1. In some embodiments, guidewire 1035 may be an interventional guidewire or a microcatheter. Guidewire 1035 may have various stiffnesses, wherein stiffer wires may be used if the composition of the CTO 1020 is less soft (e.g., fibro-fatty versus fatty plaque). A stiffer guidewire may be used when an initial softer guidewire is unable to penetrate the CTO 1020. As a part of a therapeutic procedure, e.g., balloon angioplasty, a guidewire may be intended to penetrate the CTO 1020.

[0104] The intravascular imaging catheter 1030 is positioned within the side branch 1002. The intravascular imaging catheter 1030 is depicted in a first position to generate an image associated with an imaging plane 1032. Intravascular imaging catheter 1030 may be used to determine the location of the guidewire 1035 within the main vessel 1004. As depicted, the guidewire 1035 enters the true lumen 1005 of the main vessel 1004 and penetrates the CTO 1020. Because the imaging plane 1032 of the intravascular imaging catheter 1030 intersects the guidewire 1035 in the true lumen 1005, it should appear in the cross-sectional image (Fig. 10B) associated with the imaging plane 1032. In some instances, a therapeutic procedure may intend for the guidewire 1035 to be near the radial center in the true lumen 1005 of the main vessel 1004. In that case, guidewire 1035 has been successfully positioned in the true lumen 1005. Alternatively, some therapeutic procedures may intend for a guidewire 1035 to traverse a blood vessel through the false lumen 1007. In that case, guidewire 1035 has deviated from the intended path. The cross-section view/image associated with the imaging plane is depicted in Fig. 9B.

[0105] Figure 10B is an illustration of a radial and/or tomographic cross-sectional view 1040 at an imaging plane 1032 including a intravascular imaging catheter 1030 in the side branch 1002 and a guidewire 1035 in the true lumen 1005 of a main vessel 1004, according to aspects of the present disclosure. Cross-sectional view 1040 may be an intravascular image generated from intravascular image data gathered by the intravascular imaging catheter 1030. The location of the intravascular imaging catheter 1030 is covered by a mask 1045 overlayed on the cross-sectional view 1040. The layers 1010, 1012, 1014 of the vessel wall are visible for both the side branch 1002 and main vessel 1004. As shown in Fig. 10A, the imaging plane 1032 crosses both the side branch 1002 and main vessel 1004. Thus, the lumens associated with the side branch 1002 and main vessel 1004 are present in the cross-sectional view 1040. Furthermore, the imaging plane

27 1032 crosses the true lumen 1005 and false lumen 1007 of the main vessel 1004. The false lumen 1007 has the shape of a crescent and the true lumen 1005 has the shape of a circle. The imaging catheter 1030 is in the side branch 1002 at the location of the mask 1045.

[0106] Cross-sectional view 1040 shows the location of the guidewire 1035 in the true lumen 1005 of the main vessel 1004. The cross-sectional view 1040 may be useful for determining the location of the guidewire 1035 and detecting if it is within the true lumen 1005 or false lumen 1007. Some therapeutic procedures may intend a guidewire 1035 be centered in the true lumen 1005 of the main vessel 1004, while others may intend for the guidewire 1035 to be positioned in the false lumen 1007. When there is such a requirement for guidewire location, the cross- sectional view 1040 may be beneficial to a physician performing the procedure. As depicted, guidewire 1035 fails satisfy therapeutic procedures that require the guidewire 1035 to be positioned in the false lumen 1007. However, guidewire 1035 does satisfy therapeutic procedures requiring centering of the guidewire 1035 in the true lumen 1005.

[0107] Figure 11 is a diagrammatic schematic view of CTO feature imaging and detection system 1100, according to aspects of the present disclosure. System 1100 may detect various features associated with CTOs and generate indicators to identify the feature in a display for review by a user, such as a physician. The CTO feature imaging and detection system 1100 may include live intravascular imaging 1110, CTO feature(s) detection 1120, and indicator(s) for detected CTO feature(s) 1130.

[0108] Live intravascular imaging 1110 may include use of an intraluminal imaging system 100 to gather intravascular imaging data to generate live intravascular images 1112 (e.g., radial and/or tomographic cross-sectional views). Intraluminal imaging system 100 may process the live intravascular images 1112 into live longitudinal views 1114 (e.g., image-based longitudinal view as depicted in the displays of Figs. 15-20 and/or a graphical longitudinal view). Longitudinal locations along an intravascular cross-sectional longitudinal view can be respectively correspond to individual intravascular images (radial and/or tomographic cross- sectional views). Longitudinal views are described in, for example, U.S. Publication No. 2020/0129158, U.S. Publication No. 2022/0079563, U.S. Patent No. 9,367,965, and U.S. Patent No. 10,070,827, each of which is incorporated by reference herein in its entirety. Live intravascular images 1112 and live longitudinal views 1114 may be output CTO feature(s) detection 1120 and/or screen display 1140. Images may be generated in real time or near real

28 time. Similarly, real time or near real time generated images may be displayed to a user, such as a physician, in real time or near real time.

[0109] CTO feature(s) detection 1120 uses artificial intelligence or machine learning models to detect features related to CTOs in live intravascular images 1112 and live longitudinal views 1114. In some embodiments, a convolutional neural network may be used for object detection in live intravascular images 1112 and/or live longitudinal views 1114. Machine learning model used for CTO feature(s) detection 1120 is further described in Figs. 12-14. Various features may be detected, including CTO proximal cap 1122 (e.g., as described in Figs. 3-10), interventional device(s) (e.g., guidewire, crossing wire, interventional wires, etc. as described in Figs. 3-10) 1124, intimal space and/or subintimal space 1126 (e.g., as described in Figs. 5-10), and true lumen and/or false lumen 1128 (e.g., as described in Figs. 7-10). These features may be referred to as detections.

[0110] Indicators(s) for detected CTO feature(s) 1130 may be generated based on which of the detected features 1122, 1124, 1126, 1128 have been detected by CTO feature(s) detection 1120. Indicators 1130 may take many different forms. Flags, text descriptions, and/or the use of partially transparent, colored shapes as overlays on an image in a display may be used. Multiple indicators may be used simultaneously for the same feature. For example, both a flag and text description could be used to indicate a proximal cap detection. Other combinations are also conceived of and encompassed by the present disclosure. Some non-limiting examples of indicators are depicted in Figs. 15-20.

[0111] Screen display 1140 may provide various images with indicators to a physicians to identify detected CTO features. Screen display 1140 may include live intravascular images 1112, live longitudinal view 1114, and indicator(s) for detected CTO feature(s) 1130. Figs. 15-20 depict some example displays of images including indicators for CTO features.

[0112] Figure 12 is a diagrammatic schematic view of a training system 1200 for a machine learning model 1230, according to aspects of the present disclosure. Training system 1200 trains the machine learning model 1230 to accurately detect CTO features, i.e., machine learning model may be included in CTO feature(s) detection 1120. In some embodiments, machine learning model 1230 is trained by providing historic intravascular image and/or longitudinal views alongside user-annotations of those images identifying CTO features. For example, training may done be with input comprising some or all the output of intravascular imaging 1110. In some

29 embodiments, the machine learning model 1230 may be trained to do border identification, object detection, and/or image segmentation. Training machine learning model 1230 aims to improve the performance of the model at detecting CTO features. Training system 1200 includes training data 1210, machine learning model 1230, and model objectives/functions 1250.

[0113] Training data 1410 may include data for a plurality of patient records 1220. Each patient record may contain a plurality of images or views and user annotated features therein. In some embodiments, patient record 1220 may include intravascular images (radial/tomographic) 1221, user annotation of CTO proximal cap 1223, user annotation of interventional device(s) (e.g., crossing guidewire) 1225, user annotation of intimal space and/or subintimal space 1227, and/or user annotation of true lumen and/or false lumen 1229. It should be appreciated that not all the patient records 1220 are needed to train the machine learning model 1230. For example, fewer than the four listed user annotations may be available. Furthermore, additional medical records from a patient’s medical history may be included in the training data 1210.

[0114] Machine learning model 1230 may receive the training data 1210. From the training data 1210, machine learning model 1230 may output predicted CTO feature(s) 1240. For example, the output may be a selection of pixels in the intravascular images 1221. In some embodiments, machine learning model may receive intravascular images 1221 from the training data 1210. From the intravascular images 1221, machine learning model 1230 may generate detections of CTO features, e.g., 122, 1124, 1126, 1128.

[0115] Using model objectives/functions 1250 training system 1200 compares the prediction 1240 with associated ground truth predictions. For example, in some embodiments, user annotations 1223, 1225, 1227, 1229 of CTO features comprise ground truth predictions.

[0116] In some embodiments, model objectives/functions 1250 may be used to compare predicted CTO feature(s) 1240 from a machine learning model 1230 with user annotated CTO features 1223, 1225, 1227, 1229, which represent the ground truth labels.

[0117] Model objectives/functions 1250 may include objectives/functions which penalize to a greater extent predicted CTO features 1240 which are further from the ground truth labels. In some embodiments, model objectives/functions 1250 may include objectives/functions which penalize deviations of predicted CTO feature(s) 1240 from user-annotated vessel measurements 1223, 1225, 1227, 1229.

30 [0118] Comparisons from the model objectives/functions 1250 may be used to update parameters 1260 of the machine learning model 1230. In some instances, updating may be accomplished using gradient of the objective functions and backpropagation to update the parameters of the machine learning model. The structure of machine learning models is further described with respect to Fig. 14.

[0119] Figure 13 is a second diagrammatic schematic view of a training system 1300 for a machine learning model 1380, according to aspects of the present disclosure. After training, as described in Fig. 12, is complete an untrained machine learning model with parameters A 1380 is transformed into a trained machine learning model with parameters B 1390. Parameters A and B differ between the trained and untrained models because over the course of training, parameters in the machine learning model are updated (e.g., 1260 in Fig. 12) based on comparisons between ground truth labels and predictions.

[0120] Figure 14 is a diagrammatic schematic of a deep learning network configuration 1400, according to aspects of the present disclosure. The configuration 1400 can be implemented by a deep learning network. The configuration 1400 includes a deep learning network 1410 including one or more convolutional neural networks (CNNs) 1412. The deep learning network 1410 and/or the CNNs 1412 can be referred as a predictive network. For simplicity of illustration and discussion, Fig. 14 illustrates one CNN 1412. However, the embodiments can be scaled to include any suitable number of CNNs 1412 (e.g., about 2, 3 or more). The configuration 1400 can be trained for identification of various CTO features, including proximal caps, interventional devices, intimal and subintimal spaces, and/or true and false lumens as described in greater detail below.

[0121] The CNN 1412 may include a set of N convolutional layers 1420 followed by a set of K fully connected layers 1430, where N and K may be any positive integers. The convolutional layers 1420 are shown as 1420(1) to 1420(N). The fully connected layers 1430 are shown as 1430(1) to 1430(K). Each convolutional layer 1420 may include a set of filters 1422 configured to extract features from an input 1402 (e.g., one or more intravascular image frames, imagebased longitudinal view, graphical longitudinal view, etc.). The values N and K and the size of the filters 1422 may vary depending on the embodiments. In some instances, the convolutional layers 1420(1) to 1420(N) and the fully connected layers 1430(1) to 1430(K-l) may utilize a leaky rectified non-linear (ReLU) activation function and/or batch normalization. The fully

31 connected layers 1430 may be non-linear and may gradually shrink the high-dimensional output to a dimension of the prediction result (e.g., the classification output 1440). Thus, the fully connected layers 1430 may also be referred to as a classifier. In some embodiments, the fully convolutional layers 1420 may additionally be referred to as perception or perceptive layers. [0122] The classification output 1440 may indicate a confidence score for each class 1442 based on the input image 1402. The classes 1442 are shown as 1442a, 1442b, ... , 1442c. When the CNN 1412 is trained for predicting CTO feature detections, the classes 1442 may indicate pixels for proximal cap 1442a, interventional devices 1442b, any other outputs 1442c of machine learning models as described herein, or any other suitable class. A class 1442 indicating a high confidence score indicates that the input image 1402 or a section or pixel of the image 1402 is likely to include an anatomical object/feature of the class 1442. Conversely, a class 1442 indicating a low confidence score indicates that the input image 1402 or a section or pixel of the image 1402 is unlikely to include an anatomical object/feature of the class 1442.

[0123] The CNN 1412 can also output a feature vector 1450 at the output of the last convolutional layer 1420(N). The feature vector 1450 may indicate objects detected from the input image 1402 or other data. For example, the feature vector 1450 may indicate regions associated with CTO features identified from the image 1402. The feature vector 1450 may indicate the pixels associated with CTO features, as described herein.

[0124] The deep learning network 1410 may implement or include any suitable type of learning network. For example, in some embodiments and as described in relation to Fig. 14, the deep learning network 1410 could include a convolutional neural network 1412. In addition, the convolutional neural network 1410 may additionally or alternatively be or include a multi-class classification network, an encoder-decoder type network, or any suitable network or means of identifying features within an image.

[0125] In an embodiment in which the deep learning network 1410 includes an encoderdecoder network, the network may include two paths. One path may be a contracting path, in which a large image, such as the image 1402, may be convolved by several convolutional layers 1420 such that the size of the image 1402 changes in depth of the network. The image 1402 may then be represented in a low dimensional space, or a flattened space. From this flattened space, an additional path may expand the flattened space to the original size of the image 1402. In some embodiments, the encoder-decoder network implemented may also be referred to as a principal

32 component analysis (PCA) method. In some embodiments, the encoder-decoder network may segment the image 1402 into patches.

[0126] In an additional embodiment of the present disclosure, the deep learning network

1410 may include a multi-class classification network. In such an embodiment, the multi-class classification network may include an encoder path. For example, the image 1402 may be of a high dimensional image. The image 1402 may then be processed with the convolutional layers 1420 such that the size is reduced. The resulting low dimensional representation of the image 1402 may be used to generate the feature vector 1450 shown in Fig. 14. The low dimensional representation of the image 1402 may additionally be used by the fully connected layers 1430 to regress and output one or more classes 1442. In some regards, the fully connected layers 1430 may process the output of the encoder or convolutional layers 1420. The fully connected layers 1430 may additionally be referred to as task layers or regression layers, among other terms.

[0127] Any suitable combination or variations of the deep learning network 1410 described is fully contemplated. For example, the deep learning network may include fully convolutional networks or layers or fully connected networks or layers or a combination of the two. In addition, the deep learning network may include a multi-class classification network, an encoder-decoder network, or a combination of the two.

[0128] Figure 15 is an example display 1500 of a radial and/or tomographic cross-sectional view 440 and longitudinal view 1505 with indicators for proximal cap detection, according to aspects of the present disclosure. Example display 1500 may be provided to a physician during a therapeutic procedure in real time. Display 1500 notifies the physician with a text display, “LIVE”, 1517 that the images being shown are in real time. Display 1500 may include toggleable option 1520 to turn on/activate or off/deactivate the graphical overlay indicators for CTO detections, e.g., 1510, 1515, 1520. The graphical overlays can be included in screen display while the live imaging is ongoing and make a user aware, indicate to the user, and/or alert the user of a presence of the CTO detections (e.g., an anatomical feature) in the intravascular image(s). Display 1500 includes the radial and/or tomographic cross-sectional view 440 of Fig. 4B and a longitudinal view 1505.

[0129] Cross-sectional view 440 includes a flag 1510 and graphical overlay 1520. Flag 1510 notifies the user that the displayed view includes a CTO feature. Text description near the flag, “Proximal cap” specifies the type of CTO feature detected. Overlay 1520 is located on view 440

33 where the CTO feature was detected, i.e., location of proximal cap 422. Overlay 1520 may be partially transparent, colored, and/or variously shaped. The frame number of the cross-sectional view 440 may also be shown, e.g., “Frame 130.”

[0130] Longitudinal view 1505, since it is displayed in real time (live), has a completed portion 1505 A and a greyed-out portion 1505B, which will be updated as new images are processed during live imaging. Longitudinal view 1505 includes a flag 1515. Flag 1515 notifies the user that a CTO feature has been detected in the frame where the flag is placed. Text description near the flag, “Proximal cap” specifies the type of CTO feature detected.

[0131] Figure 16 is an example display 1600 of a radial and/or tomographic cross-sectional view 440, longitudinal view 1605, and x-ray frame with contrast 1607 with indicators for proximal cap detection, according to aspects of the present disclosure. Example display 1600 may be provided to a physician for review. Display 1600 notifies the physician with a text display, “REVIEW”, 1617 that the images being shown are not in real time (i.e., not live). A user, such as a physician, may select a frame of interest from the longitudinal view 1605 to show as the cross-sectional radial and/or tomographic view 440. Display 1600 may include toggleable option 1620 to turn on/activate or off/deactivate the graphical overlay indicators for CTO detections, e.g., 1610, 1615, 1620, 1625, 1630. The graphical overlays can make a user aware, indicate to the user, and/or alert the user of a presence of the CTO detections (e.g., an anatomical feature) in the intravascular image(s). Display 1600 includes the radial and/or tomographic cross-sectional view 440 of Fig. 4B, longitudinal view 1605, and x-ray frame with contrast (angiogram) 1607.

[0132] Cross-sectional view 440 includes a flag 1610 and graphical overlay 1620. Flag 1610 notifies the user that the displayed view includes a CTO feature. Text description near the flag, “Proximal cap” specifies the type of CTO feature detected. Overlay 1620 is located on view 440 where the CTO feature was detected, i.e., location of proximal cap 422. Overlay 1620 may be partially transparent, colored, and/or variously shaped. The frame number of the cross-sectional view 440 may also be shown, e.g., “Frame 130.”

[0133] Longitudinal view 1605 includes a flag 1615 and graphical overlay 1625. Flag 1615 notifies the user that a CTO feature has been detected in the frame where the flag is placed. Text description near the flag, “Proximal cap” specifies the type of CTO feature detected. Overlay 1625 is located on longitudinal view 1605 where the CTO feature was detected, i.e., location of

34 proximal cap 422, across multiple frames. Overlay 1620 may be partially transparent, colored, and/or variously shaped.

[0134] X-ray frame with contrast 1607 includes a graphical overlay 1626 corresponding to overlay 1625 in the longitudinal view 1605, i.e., the length of the overlay 1625 in x-ray frame 1607 is corresponds to the width of the overlay 1625 in the longitudinal view. To generate the two corresponding overlays, the longitudinal view 1605 and x-ray frame with contrast 1607 may be co-registered. The overlay 1626 in the x-ray frame 1607 includes a text description, “Proximal cap,” specifying the type of CTO feature detected. Because the CTO 420 occurs at the start of the side branch 402 (i.e., a stumpless CTO) and thus prevents contrast from entering the side branch 402, it is not possible to see the side branch bifurcation from the main vessel 404. It is one of the benefits of this disclosure that a bifurcation may be detected even when there is a stumpless CTO.

[0135] An angiographic marker on the imaging catheter could further elucidate the orientation of the blocked side branch if it is not already surmised from orientation of surrounding vessels, so that interventional equipment can then be directed to the blockage. The use of radiopaque markers to identify the position and/or orientation of the imaging catheter is described in, for example, U.S. Patent No. 7,930,014, U.S. Patent No. 10,542,954, U.S. Publication No. 2014/0180068, and U.S. Publication No. 2021/0106308, each of which is incorporated by reference herein in its entirety. If the orientation of the imaging catheter is determined using the appearance of radiopaque markers in x-ray images, then the orientation of tissue in the images obtained by the imaging catheter is also known. For example, if radiopaque markers visible in x-ray images indicate that the imaging catheter is oriented with a 12 o’clock position facing up, then the tissue that is at the top of the images (e.g., side branch, CTO at start of side branch, etc.) obtained by the imaging catheter can be determined to be facing up.

[0136] Figure 17 is an example display 1700 of a radial and/or tomographic cross-sectional view 640 and longitudinal view 1705 with indicators for guidewire detection and subintimal space detection, according to aspects of the present disclosure. Example display 1700 may be provided to a physician during a therapeutic procedure in real time. Display 1700 notifies the physician with a text display, “LIVE”, 1717 that the images being shown are in real time. Display 1700 may include toggleable option 1720 to turn on/activate or off/deactivate the graphical overlay indicators for CTO detections, e.g., 1710, 1715, 1720. The graphical overlays

35 can be included in screen display while the live imaging is ongoing and make a user aware, indicate to the user, and/or alert the user of a presence of the CTO detections (e.g., an anatomical feature, an interventional device) in the intravascular image(s). Display 1700 includes the radial and/or tomographic cross-sectional view 640 of Fig. 6B and a longitudinal view 1705.

[0137] Cross-sectional view 640 includes a flag 1710 and graphical overlay 1720. Flag 1710 notifies the user that the displayed view includes a CTO feature. Text description near the flag, “Wire in subintimal space” specifies the types of CTO feature detected, e.g., an interventional device detection (wire) and subintimal space detection. In some embodiments, multiple detections may be combined into a single marker and/or text description, or each detection may have a separate marker and/or text description. Overlay 1720 is located on view 640 where the CTO feature was detected, i.e., guidewire 635, is located. Overlay 1720 may be partially transparent, colored, and/or variously shaped. The frame number of the cross-sectional view 640 may also be shown, e.g., “Frame 130.” Similarly, a display can include detection of a guidewire in the intimal space.

[0138] Longitudinal view 1705, since it is displayed in real time (live), has a completed portion 1705 A and a greyed-out portion 1705B, which will be updated as new images are processed during live imaging. Longitudinal view 1705 includes a flag 1715. Flag 1715 notifies the user that a CTO feature has been detected in the frame where the flag is placed. Text description near the flag, “Wire in subintimal space” specifies the types of CTO feature detected, e.g., an interventional device detection (wire) and subintimal space detection.

[0139] Figure 18 is an example display 1800 of a radial and/or tomographic cross-sectional view 740 and longitudinal view 1805 with indicators for true lumen and false lumen detection, according to aspects of the present disclosure. Example display 1800 may be provided to a physician during a therapeutic procedure in real time. Display 1800 notifies the physician with a text display, “LIVE”, 1817 that the images being shown are in real time. Display 1800 may include toggleable option 1820 to turn on/activate or off/deactivate the graphical overlay indicators for CTO detections, e.g., 1810, 1815, 1830, 1835, 1840. The graphical overlays can be included in screen display while the live imaging is ongoing and make a user aware, indicate to the user, and/or alert the user of a presence of the CTO detections (e.g., anatomical features) in the intravascular image(s). Display 1800 includes the radial and/or tomographic cross-sectional view 740 of Fig. 7B and a longitudinal view 1805.

36 [0140] Cross-sectional view 740 includes a flag 1810 and graphical overlays 1830, 1835, 1840. Flag 1810 notifies the user that the displayed view includes a CTO feature. Text description near the flag, “true and false lumens” specifies the types of CTO feature detected, e.g., true and false lumens. In some embodiments, multiple detections may be combined into a single marker and/or text description, or each detection may have a separate marker and/or text description. Overlays 1830, 1835, 1840 are located on view 740 where the CTO features were detected, i.e., true and false lumens. Overlay 1830 notifies the user of a true lumen of the side branch and may include the word “True” to identify which type of lumen. Overlay 1835 notifies the user of a true lumen of the main branch and may include the word “True” to identify which type of lumen. Overlay 1840 notifies the user of a false lumen of the main branch and may include the word “False” to identify which type of lumen. Overlays 1830, 1835, 1840 may be partially transparent, colored, and/or variously shaped. The frame number of the cross-sectional view 740 may also be shown, e.g., “Frame 130.” Similarly, a display can include detection of a guidewire in the intimal space.

[0141] Longitudinal view 1805, since it is displayed in real time (live), has a completed portion 1805 A and a greyed-out portion 1805B, which will be updated as new images are processed during live imaging. Longitudinal view 1805 includes a flag 1815. Flag 1815 notifies the user that a CTO features has been detected in the frame where the flag is placed. Text description near the flag, “True and false lumens” specifies the types of CTO feature detected, e.g., true and false lumens.

[0142] Figure 19 is an example display 1900 of a radial and/or tomographic cross-sectional view 740, longitudinal view 1805, and x-ray frame with contrast 1907 with indicators for true lumen and false lumen detection, according to aspects of the present disclosure. Example display 1900 may be provided to a physician for review. Display 1900 notifies the physician with a text display, “REVIEW”, 1917 that the images being shown are not in real time (i.e., not live). A user, such as a physician, may select a frame of interest from the longitudinal view 1805 to show as the cross-sectional radial and/or tomographic view 740. Display 1900 may include toggleable option 1920 to turn on/activate or off/deactivate the graphical overlay indicators for CTO detections, e.g., 1810, 1830, 1835, 1840, 1922, 1924. The graphical overlays can make a user aware, indicate to the user, and/or alert the user of a presence of the CTO detections (e.g.,

37 anatomical feature, intravascular device) in the intravascular image(s). Display 1800 includes the radial and/or tomographic cross-sectional view 740 of Fig. 7B and a longitudinal view 1805. [0143] Cross-sectional view 740 includes a flag 1810 and overlays 1830, 1835, 1840. Flag 1810 notifies the user that the displayed view includes a CTO feature. Text description near the flag, “catheter in false lumen” specifies the types of CTO feature detected, e.g., interventional devices and true and false lumens. In some embodiments, multiple detections may be combined into a single marker and/or text description, or each detection may have a separate marker and/or text description. Overlays 1830, 1835, 1840 are located on view 740 where some of the CTO features were detected, i.e., true and false lumens. Overlay 1830 notifies the user of a true lumen of the side branch and may include the word “True” to identify which type of lumen. Overlay 1835 notifies the user of a true lumen of the main branch and may include the word “True” to identify which type of lumen. Overlay 1840 notifies the user of a false lumen of the main branch and may include the word “False” to identify which type of lumen. Overlays 1830, 1835, 1840 may be partially transparent, colored, and/or variously shaped. The frame number of the cross- sectional view 740 may also be shown, e.g., “Frame 130.” Similarly, a display can include detection of a guidewire in the intimal space.

[0144] Longitudinal view 1805 may be generated from a pullback of an intravascular imaging catheter. Longitudinal view 1805 includes a flags 1922, 1924 and corresponding overlays 1923, 1925. Flag 1922 notifies the user that a CTO feature has been detected in the frames where the flag is placed. Text description near the flag, “Catheter in true lumen” specifies the type of CTO feature detected. Overlay 1923 is located on longitudinal view 1805 where the CTO feature was detected, i.e., sections of the vessel where the catheter was in a true lumen, across multiple frames. Overlay 1923 may be partially transparent, colored, and/or variously shaped. Flag 1924 notifies the user that a CTO feature has been detected in the frames where the flag is placed. Text description near the flag, “Catheter in false lumen” specifies the type of CTO feature detected. Overlay 1925 is located on longitudinal view 1805 where the CTO feature was detected, i.e., sections of the vessel where the catheter was in a false lumen, across multiple frames. Overlay 1925 may be partially transparent, colored, and/or variously shaped.

[0145] X-ray frame with contrast 1907 includes markers 1930, corresponding to flag 1922 and overlay 1923, and 1932, corresponding to flag 1924 and overlay 1925. To generate the two corresponding markers 1930 and 1932, the longitudinal view 1805 and x-ray frame with contrast

38 1907 may be co-registered. The marker 1930 in the x-ray frame 1907 includes a text description, “True,” specifying the type of CTO feature detected, i.e., catheter was in true lumen. The marker 1932 in the x-ray frame 1907 includes a text description, “False,” specifying the type of CTO feature detected, i.e., catheter was in false lumen.

[0146] Figure 20 is an example display 2000 of a radial and/or tomographic cross-sectional view 940 and longitudinal view 2005 with indicators for guidewire detection and false lumen detection, according to aspects of the present disclosure. Example display 2000 may be provided to a physician during a therapeutic procedure in real time. Display 2000 notifies the physician with a text display, “LIVE”, 2017 that the images being shown are in real time. Display 2000 may include toggleable option 2020 to turn on/activate or off/deactivate the graphical overlay indicators for CTO detections, e.g., 2010, 2015, 2020. The graphical overlays can be included in screen display while the live imaging is ongoing and make a user aware, indicate to the user, and/or alert the user of a presence of the CTO detections (e.g., anatomical features, intervention device) in the intravascular image(s). Display 2000 includes the radial and/or tomographic cross- sectional view 940 of Fig. 9B and a longitudinal view 2005.

[0147] Cross-sectional view 940 includes a flag 2010 and graphical overlay 2020. Flag 2010 notifies the user that the displayed view includes a CTO feature. Text description near the flag, “Wire in false lumen” specifies the types of CTO feature detected, e.g., an interventional device detection (wire) and false lumen detection. Overlay 2020 is located on view 940 where the CTO feature was detected, i.e., guidewire 935. Overlay 2020 may be partially transparent, colored, and/or variously shaped. The frame number of the cross-sectional view 940 may also be shown, e.g., “Frame 130.”

[0148] Longitudinal view 2005, since it is displayed in real time (live), has a completed portion 2005A and a greyed-out portion 2005B, which will be updated as new images are processed during live imaging. Longitudinal view 2005 includes a flag 2015. Flag 2015 notifies the user that a CTO feature has been detected in the frame where the flag is placed. Text description near the flag, “Wire in false lumen” specifies the types of CTO feature detected, e.g., an interventional device detection (wire) and false lumen detection.

[0149] Irrespective of whether an imaging catheter is in a side branch, main vessel, true lumen, false lumen, intimal space, or subintimal space, the various features displayed and discussed here can be imaged, even when the structures of the vasculature, CTOs, and/or wires

39 are in a separate section of the vasculature from the catheter. For example, an imaging catheter in the main branch false lumen can image the true lumen of the main branch and a side branch.

[0150] Other displays may be constructed using the CTO features, detections, indicators as described herein. It should be appreciated there many ways to depict the overlays, flags, markers, and text descriptions in a display. For example, the use of color, shading, transparency, and other features may be used in the overlay. Symbolic representations other than a flag may be used. [0151] The logical operations making up the aspects of the technology described herein are referred to variously as operations, steps, objects, elements, components, modules, etc. Furthermore, it should be understood that these may occur or be performed or arranged in any order, unless explicitly claimed otherwise or a specific order is inherently necessitated by the claim language.

[0152] As used herein, the term “blood vessel” may refer to both a main vessel and side branch or “blood vessel” may refer to the main vessel. It will be apparent from the context which use of “blood vessel” is intended.

[0153] All directional references e.g., upper, lower, inner, outer, upward, downward, left, right, lateral, front, back, top, bottom, above, below, vertical, horizontal, clockwise, counterclockwise, proximal, and distal are only used for identification purposes to aid the reader’s understanding of the claimed subject matter, and do not create limitations, particularly as to the position, orientation, or use of the stent placement planning system. Connection references, e.g., attached, coupled, connected, joined, or “in communication with” are to be construed broadly and may include intermediate members between a collection of elements and relative movement between elements unless otherwise indicated. As such, connection references do not necessarily imply that two elements are directly connected and in fixed relation to each other. The term “or” shall be interpreted to mean “and/or” rather than “exclusive or.” The word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. Unless otherwise noted in the claims, stated values shall be interpreted as illustrative only and shall not be taken to be limiting.

[0154] The above specification, examples and data provide a complete description of the structure and use of exemplary aspects of the CTO feature imaging and detection system as defined in the claims. Although various aspects of the claimed subject matter have been described above with a certain degree of particularity, or with reference to one or more

40 individual aspects, those skilled in the art could make numerous alterations to the disclosed aspects without departing from the spirit or scope of the claimed subject matter.

[0155] The modules described herein can be software, firmware, hardware, or a combination of them. The processor circuit can include, implement, and/or execute the modules (e.g., the software, firmware, hardware, or a combination of them).

[0156] A system of one or more computers can be configured to perform particular operations or actions by virtue of having software, firmware, hardware, or a combination of them installed on the system that in operation causes or cause the system to perform the actions. One or more computer programs can be configured to perform particular operations or actions by virtue of including instructions that, when executed by data processing apparatus, cause the apparatus to perform the actions.

[0157] One general aspect includes an apparatus including a processor circuit configured for communication with an intravascular imaging catheter, where the processor circuit is configured to: control the intravascular imaging catheter to obtain a plurality of intravascular images of a first blood vessel of vasculature while positioned within the vasculature, where the first blood vessel may include a chronic total occlusion (CTO); identify at least one of an anatomical feature associated with the CTO or an interventional device for treatment of the CTO in an intravascular image of the plurality of intravascular images; output, to a display in communication with the processor circuit, a screen display may include: the intravascular image; and a visual representation associated with at least one of the anatomical feature or the interventional device, where the visual representation is configured to provide an indication, to a user, of the identification of at least one of the anatomical feature or the interventional device in the intravascular image. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0158] Implementations may include one or more of the following features. The apparatus where the visual representation may include a graphical overlay located on the intravascular image. The visual representation may include a text description located on or proximate to the intravascular image. The processor circuit is configured to control the intravascular imaging catheter to obtain the plurality of intravascular images during live imaging, where the processor circuit is configured to identify at least one of the anatomical feature or the interventional device

41 and output the screen display while the live imaging is ongoing. The anatomical feature may include at least one of a proximal cap, an intimal space, a sub-intimal space, a true lumen, or a false lumen. The interventional device may include at least one of a crossing guidewire or a guide catheter. To identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to determine if the interventional device located within an intimal space or a sub-intimal space. The predictive network may include a convolutional neural network (CNN). To identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to determine if the interventional device located within a true lumen or a false lumen. To identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to determine if at least one of the intravascular imaging catheter is located within a true lumen or a false lumen. The screen display may include a user-selectable option to activate or deactivate an appearance of the visual representation in the screen display. To identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to: provide the plurality of intravascular images as an input to a predictive network trained using a further plurality of intravascular images annotated with a plurality of locations of at least one of the anatomical feature or the interventional device; and generate a detection of at least one of the anatomical feature or the interventional device as an output of the predictive network. The anatomical feature may include a proximal cap, where the processor circuit is configured to perform co-registration between the plurality of intravascular images and an x-ray image of the vasculature with contrast, where the CTO may include a stumpless CTO such that a location where the first blood vessel is connected to a second blood vessel is not visible in the x-ray image, where the screen display further may include the x-ray image, where the visual representation is overlaid on the x-ray image and configured to provide the indication to the user, based on the identification of the proximal cap, of the location where the first blood vessel is connected to a second blood vessel. The apparatus may include the intravascular imaging catheter. The intravascular imaging catheter is configured to obtain the plurality of intravascular images while positioned within a false lumen of the first blood vessel The vasculature may include a second blood vessel connected to the first blood vessel, where the intravascular imaging catheter is configured to obtain the plurality of intravascular images while positioned within: the second blood vessel; or a location where the first blood vessel and the

42 second blood vessel are connected. Implementations of the described techniques may include hardware, a method or process, or computer software on a computer-accessible medium.

[0159] One general aspect includes a method. The method also includes controlling, with a processor circuit, an intravascular imaging catheter to obtain a plurality of intravascular images of a first blood vessel of vasculature while positioned within the vasculature, where the first blood vessel may include a chronic total occlusion (cto); identifying, with the processor circuit, at least one of an anatomical feature of the cto or an interventional device for treatment of the cto in an intravascular image of the plurality of intravascular images; outputting, to a display in communication with the processor circuit, a screen display may include: the intravascular image; and a visual representation associated with at least one of the anatomical feature or the interventional device, where the visual representation is configured to provide an indication, to a user, of a presence of at least one of the anatomical feature or the interventional device in the intravascular image. Other embodiments of this aspect include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the methods.

[0160] Still other aspects are contemplated. It is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative only of particular aspects and not limiting. Changes in detail or structure may be made without departing from the basic elements of the subject matter as defined in the following claims.

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Claims

CLAIMS What is claimed is:

1. An apparatus, comprising: a processor circuit configured for communication with an intravascular imaging catheter, wherein the processor circuit is configured to: control the intravascular imaging catheter to obtain a plurality of intravascular images of a first blood vessel of vasculature while positioned within the vasculature, wherein the first blood vessel comprises a chronic total occlusion (CTO); identify at least one of an anatomical feature associated with the CTO or an interventional device for treatment of the CTO in an intravascular image of the plurality of intravascular images; output, to a display in communication with the processor circuit, a screen display comprising: the intravascular image; and a visual representation associated with at least one of the anatomical feature or the interventional device, wherein the visual representation is configured to provide an indication, to a user, of the identification of at least one of the anatomical feature or the interventional device in the intravascular image.

2. The apparatus of claim 1, wherein the visual representation comprises a graphical overlay located on the intravascular image.

3. The apparatus of claim 1, wherein the visual representation comprises a text description located on or proximate to the intravascular image.

4. The apparatus of claim 1, wherein the processor circuit is configured to control the intravascular imaging catheter to obtain the plurality of intravascular images during live imaging, wherein the processor circuit is configured to identify at least one of the anatomical feature or the interventional device and output the screen display while the live imaging is ongoing.

5. The apparatus of claim 1, wherein the anatomical feature comprises at least one of a proximal cap, an intimal space, a sub-intimal space, a true lumen, or a false lumen.

6. The apparatus of claim 1, wherein the interventional device comprises at least one of a crossing guidewire or a guide catheter.

7. The apparatus of claim 1 , wherein, to identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to determine if the interventional device located within an intimal space or a sub-intimal space.

8. The apparatus of claim 1, wherein, to identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to determine if the interventional device located within a true lumen or a false lumen.

9. The apparatus of claim 1 , wherein, to identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to determine if at least one of the intravascular imaging catheter is located within a true lumen or a false lumen.

10. The apparatus of claim 1, wherein the screen display comprises a user-selectable option to activate or deactivate an appearance of the visual representation in the screen display.

11. The apparatus of claim 1, wherein, to identify at least one of the anatomical feature or the interventional device, the processor circuit is configured to: provide the plurality of intravascular images as an input to a predictive network trained using a further plurality of intravascular images annotated with a plurality of locations of at least one of the anatomical feature or the interventional device; and

45 generate a detection of at least one of the anatomical feature or the interventional device as an output of the predictive network.

12. The apparatus of claim 11, wherein the predictive network comprises a convolutional neural network (CNN).

13. The apparatus of claim 1, wherein the anatomical feature comprises a proximal cap, wherein the processor circuit is configured to perform co-registration between the plurality of intravascular images and an x-ray image of the vasculature with contrast, wherein the CTO comprises a stumpless CTO such that a location where the first blood vessel is connected to a second blood vessel is not visible in the x-ray image, wherein the screen display further comprises the x-ray image, wherein the visual representation is overlaid on the x-ray image and configured to provide the indication to the user, based on the identification of the proximal cap, of the location where the first blood vessel is connected to a second blood vessel.

14. The apparatus of claim 1, further comprising the intravascular imaging catheter.

15. The apparatus of claim 14, wherein the intravascular imaging catheter is configured to obtain the plurality of intravascular images while positioned within a false lumen of the first blood vessel.

16. The apparatus of claim 1, wherein the vasculature comprises a second blood vessel connected to the first blood vessel, wherein the intravascular imaging catheter is configured to obtain the plurality of intravascular images while positioned within: the second blood vessel; or a location where the first blood vessel and the second blood vessel are connected.

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17. A method, comprising: controlling, with a processor circuit, an intravascular imaging catheter to obtain a plurality of intravascular images of a first blood vessel of vasculature while positioned within the vasculature, wherein the first blood vessel comprises a chronic total occlusion (CTO); identifying, with the processor circuit, at least one of an anatomical feature of the CTO or an interventional device for treatment of the CTO in an intravascular image of the plurality of intravascular images; outputting, to a display in communication with the processor circuit, a screen display comprising: the intravascular image; and a visual representation associated with at least one of the anatomical feature or the interventional device, wherein the visual representation is configured to provide an indication, to a user, of the identification of at least one of the anatomical feature or the interventional device in the intravascular image.