A push-forward type optical coherence tomography image acquisition method and device

Abstract

The application provides a forward pushing type optical coherence tomography image acquisition method and device. The method comprises the following steps: determining a blood flow velocity curve changing with a heart cycle according to a first contrast image sequence obtained by inserting a catheter and releasing contrast agent and a heart cycle timing signal; correcting blood flow velocity in a target blood vessel of a target patient according to a second contrast image obtained after the catheter is inserted, and determining a contrast agent unit release amount matched with the corrected blood flow velocity curve changing with the heart cycle; injecting the contrast agent according to the contrast agent unit release amount; when an imaging signal returned by a probe indicates that the contrast agent covers the probe, controlling the probe to push forward until reaching a specified position at a distal end of a lesion, and acquiring images in the process of pushing forward. In this way, the application realizes reduction of the amount of contrast agent while ensuring imaging quality by adopting a forward pushing type probe moving in the same direction as blood flow and correcting the amount of contrast agent release in combination with a personalized blood flow velocity curve.

Description

Technical Field

[0001] This application relates to the field of medical auxiliary technology, and in particular to a forward-pushing optical coherence tomography image acquisition method and device. Background Technology

[0002] Optical coherence tomography (OCT) is a common coronary imaging technique primarily used to diagnose vascular stenosis, arteriosclerosis, and guide stent placement. It involves inserting a catheter into the coronary artery through a guidewire at the aorta's coronary ostium. The distal end of the catheter enters the coronary artery first, reaching the vicinity of the lesion for imaging. Current technology requires the imaging probe to be pulled back a certain distance from the distal end to the proximal end of the catheter to scan a segment of the vessel. This pullback direction is opposite to the direction of blood flow in the coronary artery. Since light cannot penetrate blood, additional contrast agent is injected during imaging to temporarily clear the blood near the lesion. This causes the contrast agent to flow in the opposite direction to the probe's pullback. This necessitates the injection of a large amount of contrast agent to ensure the probe can still clearly visualize the vessel wall during the reverse pullback.

[0003] However, the contrast agents used during coronary angiography may affect kidney function, especially in patients with renal insufficiency. Therefore, the total amount of contrast agent used in coronary surgery needs to be monitored. The use of OCT imaging increases the amount of contrast agent used, undoubtedly raising the surgical risk. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a forward-push optical coherence tomography image acquisition method and device, which achieves a significant reduction in contrast agent usage while ensuring imaging quality by using a forward-push probe that moves in the same direction as the blood flow and combining it with a personalized blood flow velocity curve to correct the amount of contrast agent released.

[0005] This application provides a method for acquiring forward-push optical coherence tomography (OCT) images, the method comprising: Based on the first contrast image sequence before catheter insertion and release of contrast agent, as well as the cardiac cycle timing signal, the blood flow velocity curve that varies with the cardiac cycle was determined. Based on the second angiographic image where the catheter is inserted to a designated location distal to the lesion and the release of contrast agent is stopped, the blood flow velocity in the target vessel of the target patient is corrected to determine the unit release amount of contrast agent that matches the corrected blood flow velocity curve that varies with the cardiac cycle. Once the imaging catheter probe is moved to the designated location proximal to the lesion, the contrast agent is injected according to the unit release dose, and the imaging signal transmitted back by the probe is monitored. When it is determined from the imaging signal that the contrast agent covers the probe, the probe is controlled to be pushed forward until it reaches the designated position at the distal end of the lesion, and image acquisition is performed during the advancement process.

[0006] Optionally, determining the blood flow velocity curve that varies with the cardiac cycle based on the first contrast image sequence before catheter insertion and release of contrast agent, and the cardiac cycle timing signal, includes: Before catheter insertion, contrast agent is injected into the blood vessel to acquire contrast images and record cardiac cycle signals, thereby obtaining the first contrast image sequence and cardiac cycle timing signal. Blood flow velocity is determined based on the interface movement data between contrast agent and blood in the first contrast image sequence; The blood flow velocity is correlated with the synchronously recorded cardiac cycle time-series signal to obtain a blood flow velocity curve that varies with the cardiac cycle.

[0007] Optionally, the step of correcting the blood flow velocity in the target vessel of the target patient based on a second angiographic image obtained by inserting the catheter to a designated location distal to the lesion and stopping the release of contrast agent, and determining a unit release amount of contrast agent that matches the corrected blood flow velocity curve varying with the cardiac cycle, includes: Stop releasing the contrast agent and acquire a second contrast image of the catheter at a designated location distal to the lesion; The projected length of the catheter is obtained based on the second contrast image; The intravascular volume with the catheter is calculated based on the projected length and cross-sectional area of ​​the catheter. The unit release amount of contrast agent is determined based on the intravascular volume with catheter and the blood flow velocity curve.

[0008] Optionally, controlling the probe to push forward until it reaches a designated location distal to the lesion includes: The probe is pushed toward a designated location distal to the lesion at a propulsion speed not exceeding the lowest blood flow velocity in the blood flow velocity curve.

[0009] Optionally, when controlling the probe to push forward until it reaches a designated location distal to the lesion, and acquiring images during the advancement process, the method further includes: The release time of the contrast agent is determined based on the probe's moving distance and the contrast agent's moving speed; wherein the release time is earlier than the time when the probe reaches the designated position at the distal end of the lesion; At the determined stop release time, the injection of the contrast agent is controlled to stop.

[0010] Optionally, the movement velocity of the contrast agent is the average diastolic blood flow velocity in the blood flow velocity curve or the average blood flow velocity throughout the cardiac cycle.

[0011] Optionally, the probe is installed in a push-type OCT image acquisition device. When the probe is pushed to a designated location at the distal end of the lesion, it moves along a guide rail inside an outer tube fixed in the push-type OCT image acquisition device. The outer tube is inserted into the vicinity of the stenosis through a catheter.

[0012] This application embodiment also provides a forward-push optical coherence tomography image acquisition device, the image acquisition device comprising: The determination module is used to determine the blood flow velocity curve that varies with the cardiac cycle based on the first contrast image sequence before catheter insertion and release of contrast agent and the cardiac cycle timing signal; The calibration module is used to correct the blood flow velocity in the target vessel of the target patient based on the second angiographic image of the catheter inserted to a specified position at the distal end of the lesion and the release of contrast agent is stopped, and to determine the unit release amount of contrast agent that matches the corrected blood flow velocity curve that changes with the cardiac cycle. The release module is used to inject contrast agent according to the unit release amount after the probe of the imaging catheter is moved to a designated position proximal to the lesion, and to monitor the imaging signal transmitted back by the probe. The control module is used to control the probe to push forward until it reaches a designated position at the distal end of the lesion when it is determined from the imaging signal that the contrast agent covers the probe, and to acquire images during the advancement process.

[0013] This application also provides an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the image acquisition method described above are performed.

[0014] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the image acquisition method described above.

[0015] This application provides a method and apparatus for forward-pushing optical coherence tomography (OCT) image acquisition. The method includes: determining a blood flow velocity curve that varies with the cardiac cycle based on a first contrast image sequence before catheter insertion and contrast agent release, and a cardiac cycle timing signal; correcting the blood flow velocity in the target vessel of the target patient based on a second contrast image after catheter insertion to a designated location distal to the lesion and contrast agent release is stopped, and determining a contrast agent unit release amount that matches the corrected blood flow velocity curve that varies with the cardiac cycle; injecting contrast agent according to the said contrast agent unit release amount after the imaging catheter probe moves to a designated location proximal to the lesion, and monitoring the imaging signal returned by the probe; and controlling the probe to push forward until it reaches the designated location distal to the lesion, and acquiring images during the advancement process, when it is determined from the imaging signal that the contrast agent covers the probe. In this way, by controlling the probe to push forward, the probe's movement direction is aligned with the blood flow direction, reducing the length of blood that needs to be displaced and thus reducing the amount of contrast agent required; by pre-measuring the patient's own blood flow dynamics, the contrast agent release amount is adjusted accordingly to achieve precise drug delivery; by using the probe's real-time signal as feedback, scanning is only started after the contrast agent has reached its destination, avoiding ineffective injection; and by using the probe's movement distance and the contrast agent's movement speed, the timing of stopping the contrast agent release is determined, avoiding unnecessary injection of contrast agent.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart of a forward-pushing optical coherence tomography image acquisition method provided in this application embodiment; Figure 2 This application provides a schematic diagram of the structure of a forward-pushing OCT image acquisition device; Figure 3 An enlarged schematic diagram of the distal end of the catheter in the push-type OCT image acquisition device provided in this application; Figure 4 This is a schematic cross-sectional view of the distal end of the catheter in a push-type OCT image acquisition device; Figure 5A schematic diagram of the first contrast-enhanced image sequence provided in this application; Figure 6 This is a schematic diagram illustrating the principle of OCT imaging in this scheme compared to existing technologies; Figure 7 A schematic diagram of a forward-pushing optical coherence tomography image acquisition device provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0020] Optical coherence tomography (OCT) is a common coronary imaging technique primarily used to diagnose vascular stenosis, arteriosclerosis, and guide stent placement. It involves inserting a catheter into the coronary artery through a guidewire at the aorta's coronary ostium. The distal end of the catheter enters the coronary artery first, reaching the vicinity of the lesion for imaging. Current technology requires the imaging probe to be pulled back a certain distance from the distal end to the proximal end of the catheter to scan a segment of the vessel. This pullback direction is opposite to the direction of blood flow in the coronary artery. Since light cannot penetrate blood, additional contrast agent is injected during imaging to temporarily clear the blood near the lesion. This causes the contrast agent to flow in the opposite direction to the probe's pullback. This necessitates the injection of a large amount of contrast agent to ensure the probe can still clearly visualize the vessel wall during the reverse pullback.

[0021] However, the contrast agents used during coronary angiography may affect kidney function, especially in patients with renal insufficiency. Therefore, the total amount of contrast agent used in coronary surgery needs to be monitored. The use of OCT imaging increases the amount of contrast agent used, undoubtedly raising the surgical risk.

[0022] Based on this, the present application provides a forward-push optical coherence tomography image acquisition method and device. By using a forward-push probe that moves in the same direction as the blood flow and combining it with a personalized blood flow velocity curve to correct the amount of contrast agent released, the amount of contrast agent used can be significantly reduced while ensuring the imaging quality.

[0023] Please see Figure 1 , Figure 1 This is a flowchart of a forward-pushing optical coherence tomography image acquisition method provided in an embodiment of this application.

[0024] It should be noted that this method is applied to push-type OCT image acquisition devices. For an example, please refer to [link / reference needed]. Figure 2 , Figure 3 as well as Figure 4 , Figure 2 This is a schematic diagram of the structure of a forward-pushing OCT image acquisition device provided in this application. Figure 3 This is an enlarged schematic diagram of the distal end of the catheter in the push-type OCT image acquisition device provided in this application. Figure 4 This is a schematic cross-sectional view of the distal end of the catheter in a forward-push OCT image acquisition device. (Example) Figure 2 As shown, the forward-pushing OCT image acquisition device includes: a catheter 100, a guide ring 102, a probe 103, an inner tube 104, an outer tube 105, a telescopic part 106, a proximal connector 108, a catheter connector 109, an interactive connector 110, a patient interaction unit 111, an engine 112, an OCT module 113, and a computer 114. The catheter 100 is divided into a proximal end 1001 and a distal end 1002. The inner tube 104 of the catheter 100 has an imaging probe 103 at its distal end. The probe 103 is fixedly connected to a guide ring 102. This guide ring 102 can move along the guide rail 115 (… Figure 3 (As shown in the diagram) The sliding mechanism improves the trackability of the probe 103 as it is advanced distally, preventing damage to the outer tube 105 or breakage of the probe 103 due to impact or strong friction with the inner wall of the outer tube 105 during rapid advancement. The telescopic part 106 ensures that the outer tube 105 remains relatively stationary relative to the blood vessel during the advancement of the inner tube 104. The catheter connector 109 in the proximal connector 108 can connect to the interaction connector 110 in the patient interaction unit 111 of the OCT engine 112, thereby transmitting the OCT signal to the OCT module for further processing.

[0025] like Figure 3 As shown, Figure 3This is an enlarged view of the distal end 1002 of the catheter. The outer tube 105 contains an inner tube 104 and a guide ring 102 at the distal end of the inner tube. The inner tube 104 can slide relative to the outer tube 105. An optical fiber 203 is located in the middle of the inner tube 104. OCT imaging light propagates through the inner fiber 204 and enters the self-focusing lens 205, where it is focused and incident on the surface of the reflecting mirror 208. The reflecting mirror 208 is mounted on a micromotor 206. The rotation of the micromotor 206 drives the reflecting mirror 208, causing the emitted OCT imaging light to scan a 360° circle, thus achieving imaging of the blood vessel wall. The micromotor 206 is fixed to the inner tube 104.

[0026] Figure 4 for Figure 3 Cross-sectional view of section AA'. The guide ring 102 has two inner cavities, with the micro motor 206 fixed in one of the larger cavities. The smaller cavity is the guide hole 301, within which the guide rail 115 can slide freely.

[0027] Before implementing this solution, the OCT probe and guide rail 115 need to be installed. The specific process is as follows: Manufacturing guide rail 115, guide rail ring 102, outer tube 105, inner tube 104, self-focusing lens 205, and reflector 208; preparing micro motor 206, optical fiber 203, and telescopic part 106; a guide rail hole 301 is opened on the edge of guide rail ring 102, and guide rail hole 301 is clearance-fitted with guide rail 115; Installing the OCT probe and inner tube 104: First, fix the self-focusing lens 205 to the distal end of optical fiber 203, then fix optical fiber 203 and inner tube 104; then fix the reflector 208 to the rotating part of micro motor 206, then fix the housing of micro motor 206 in guide rail ring 102; finally, fix guide rail ring 102 to the distal end of inner tube 104; Installing guide rail 115: on the outer tube 105... A guide rail fixing end 209 is machined at the distal end, and the distal end of the guide rail 115 is fixed to the guide rail fixing end 209; Assembly: the guide rail 115 is inserted along the guide rail hole 301 of the guide rail ring 102, and then the inner tube 104 is pushed to the distal end. After cutting the guide rail 115, the proximal end of the guide rail 115 is fixed to the outer tube 105; a conduit connector 109 is installed at the proximal end of the optical fiber 203; the proximal ends of the inner tube 104 and the outer tube 105 are respectively fixed to the inner and outer components of the telescopic part 106, and the inner and outer components are slidably connected. The telescopic part 106 is provided with an inner tube driver to realize the movement (pushing or pulling back) of the inner tube 104. The control system sends a signal to the inner tube driver to control the acquisition speed of the OCT probe; the inner tube driver pushes the inner tube 104 (and the guide rail ring 102) to realize the change of the position of the OCT probe.

[0028] In this embodiment, the guide rail fixing end 209 and the outer tube 105 are integrally structured, which can be regarded as a protrusion at the distal end of the outer tube 105. A certain gap is provided between the guide rail 115 and the outer tube 105 to install the guide rail ring 102, allowing the guide rail ring 102 to slide along the guide rail 115. Simultaneously, the OCT probe also slides along the guide rail 115. The wire 207, which provides power to the micro motor 206, is connected to the control system through the gap between the inner tube 104 and the outer tube 105. During the process of pushing and collecting data, the OCT probe rotates. This rotation is achieved by the micro motor 206. The rotation of the micro motor 206 rotates the reflector 208 in the OCT probe, thereby changing the angle of the acquired signal and achieving imaging of the blood vessel wall. During operation, the OCT imaging light propagates through the inner fiber 204 and enters the self-focusing lens 205. After being focused, it is incident on the surface of the reflector 208. The reflected OCT imaging light is emitted into the tissue. The signal is reflected by the tissue interface and then returns along the same path. It is transmitted sequentially through the optical fiber 203, the catheter connector 109, and the cross connector 110 before entering the OCT data processing module of the control system for processing into an image file.

[0029] For details on the acquisition and imaging process of vascular target images, please refer to [link / reference needed]. Figure 1 ,like Figure 1 As shown in the figure, the push-forward optical coherence tomography image acquisition method provided in this application includes: S101. Based on the first contrast image sequence before catheter insertion and release of contrast agent and the cardiac cycle timing signal, determine the blood flow velocity curve that changes with the cardiac cycle.

[0030] S102. Based on the second contrast image where the catheter is inserted to the designated location distal to the lesion and the release of contrast agent is stopped, the blood flow velocity in the target vessel of the target patient is corrected, and the unit release amount of contrast agent is determined to match the corrected blood flow velocity curve that varies with the cardiac cycle. S103. After the imaging catheter probe is moved to the designated position proximal to the lesion, the contrast agent is injected according to the unit release amount of the contrast agent, and the imaging signal transmitted back by the probe is monitored.

[0031] S104. When it is determined from the imaging signal that the contrast agent covers the probe, control the probe to push forward until it reaches the designated position at the distal end of the lesion, and perform image acquisition during the advancement process.

[0032] The exemplary steps of the embodiments of this application are described below: Regarding step S101, in this step, before inserting the catheter, specifically during the insertion of the guidewire, the cardiac cycle timing signal can be determined by an electrocardiogram or aortic pressure curve. The purpose of recording the cardiac cycle timing signal is to clearly know the cardiac cycle corresponding to each frame of the first angiography image.

[0033] Furthermore, in one embodiment provided in this application, determining the blood flow velocity curve that varies with the cardiac cycle based on the first contrast image sequence before catheter insertion and release of contrast agent and the cardiac cycle timing signal includes: S1011. Without inserting a catheter, inject contrast agent into the blood vessel, perform angiography image acquisition and cardiac cycle signal recording, and obtain the first angiography image sequence and cardiac cycle timing signal. S1012. Determine the blood flow velocity based on the interface movement data between the contrast agent and blood in the first contrast image sequence; S1013. The blood flow velocity is correlated with the synchronously recorded cardiac cycle time sequence signal to obtain a blood flow velocity curve that changes with the cardiac cycle.

[0034] Regarding step S1012, in this step, when determining the blood flow velocity based on the interface movement data between the contrast agent and blood in the first contrast image sequence, the specific steps include: for each frame of the first contrast image, identifying the interface between the contrast agent and blood in the image, and calculating the projection data of the blood flow interface based on the identified interface; and determining the blood flow velocity based on the projection data in each contrast image and the acquisition speed of each contrast image.

[0035] For an example, please refer to Figure 5 , Figure 5 A schematic diagram of the first contrast-enhanced image sequence provided in this application. Figure 5 The image shows three consecutive first-line contrast images, depicting the contrast agent flow at three different times. The white arrows indicate the interface between the contrast agent and blood as the contrast agent flows from the left main artery to the left anterior descending artery. By detecting this interface, the area of ​​the vessel containing the contrast agent can be obtained, allowing the calculation of the blood velocity.

[0036] Regarding step S102, in one embodiment provided in this application, the step of correcting the blood flow velocity in the target vessel of the target patient based on the second contrast image obtained by inserting the catheter to a designated location distal to the lesion and stopping the release of contrast agent, and determining the unit release amount of contrast agent that matches the corrected blood flow velocity curve that varies with the cardiac cycle, includes: S1021. Stop releasing the contrast agent and acquire a second contrast image at the designated location distal to the lesion using the catheter; S1022. Obtain the projected length of the catheter based on the second contrast image; S1023. Calculate the intravascular volume when the catheter is present based on the projected length of the catheter and the cross-sectional area of ​​the catheter. S1024. Determine the unit release amount of contrast agent based on the intravascular volume when the catheter is present and the blood flow velocity curve.

[0037] For step S1021, the specified location at the distal end of the lesion can be: the location at a first distance from the lesion location.

[0038] In step S1022, the catheter in the second contrast image is identified, and the projected length of the catheter is determined based on the identified catheter information.

[0039] For step S1023, the cross-sectional area of ​​the conduit can be predetermined.

[0040] For step S1023, the blood flow velocity curve is corrected based on the intravascular volume when the catheter is present, and the unit release amount of contrast agent is determined based on the corrected blood flow velocity curve.

[0041] It should be noted that since the blood flow interface projection data calculated in step 101 is the area within the blood vessel before the OCT imaging catheter, calculating the blood flow velocity based on this would result in a lower calculated velocity, potentially leading to insufficient contrast agent. This is especially important because the final flow velocity will differ between different branches due to stenosis (or lesions) within the blood vessel; therefore, this calculation is crucial. Specifically, in step 102, after catheter placement, the cross-sectional area available for blood flow decreases. The difference between these two flow rates is calculated based on the catheter insertion volume, thus more accurately estimating the actual release volume per unit volume. Regarding calculation time, since no contrast agent is released during this process, the length of the catheter projection can be quickly obtained directly from the catheter's shadow in the imaging image.

[0042] For step S103, the movement path of the probe from the current position to the specified position proximal to the lesion is determined, and the catheter is controlled to move to the specified position proximal to the lesion according to the determined movement path. Then, the contrast agent is injected at the unit release volume, and the imaging signal transmitted back by the probe is monitored.

[0043] Here, the specified location near the proximal end of the lesion can specifically be the location at the second distance from the lesion location.

[0044] Regarding step S104, in this step, controlling the probe to push forward until it reaches the designated position at the distal end of the lesion includes: pushing the probe toward the designated position at the distal end of the lesion at a propulsion speed not greater than the lowest blood flow velocity in the blood flow velocity curve.

[0045] Here, the lowest blood flow velocity in the blood flow velocity curve can be the lowest blood flow velocity determined in step S101, or it can be the lowest blood flow velocity in the blood flow velocity curve after correction of the intravascular volume when passing through the catheter in step S102.

[0046] Furthermore, controlling the probe to push forward until it reaches the designated location at the distal end of the lesion includes: controlling the probe to push forward at a constant speed until it reaches the designated location at the distal end of the lesion.

[0047] Continuing with step S104, in one embodiment provided in this application, when controlling the probe to move forward until it reaches a designated location distal to the lesion, and acquiring images during the advancement process, the method further includes: determining the time at which the contrast agent stops releasing based on the probe's moving distance and the contrast agent's moving speed; wherein the time at which the contrast agent stops releasing is earlier than the time when the probe reaches the designated location distal to the lesion; and controlling the contrast agent to stop injection at the determined time at which the contrast agent stops releasing. The moving speed of the contrast agent is the average diastolic blood flow velocity in the blood flow velocity curve or the average blood flow velocity throughout the entire cardiac cycle.

[0048] Here, stopping the release of contrast agent earlier than the OCT probe stops pushing can reduce the amount of contrast agent used while still meeting imaging requirements.

[0049] For further details, please refer to Figure 6 , Figure 6 This is a schematic diagram illustrating the principle of OCT imaging using this method and existing technologies. (Combined with...) Figure 6 The following describes how this application reduces the amount of contrast agent compared to existing technologies: During the imaging process of the method used in this embodiment, the direction of movement of the imaging probe is consistent with the direction of blood flow; as... Figure 6 As shown, for example, the probe needs to measure the length of segment AB of the blood vessel. l Imaging is performed on a portion of the blood vessel. Assuming a blood flow velocity of v, typically between 10 cm / s and 40 cm / s. The probe velocity is u, currently generally 10 cm / s, but this can be increased with future technological advancements. The contrast agent, simply put, displaces the blood flow from the probe between the start of imaging (t0) and the completion of imaging (t0+Δt), allowing the probe beam to directly illuminate the vessel wall. This is done using the vessel as a reference frame. l =u×Δt. In existing OCT probes, the blood and probe move in opposite directions; the relative displacement between the blood and probe is (u+v)×Δt. This means that the blood within this relative displacement needs to be pushed aside for the probe to see the vessel wall. However, when using a push-type catheter for collection, the blood and probe move in the same direction. The relative displacement between the blood and probe is (uv)×Δt. For example... Figure 6As shown, with a blood flow velocity of 30 cm / s and a probe movement speed of 10 cm / s, pushing the probe forward saves 50% of the contrast agent compared to pulling it back; if the probe movement speed is even faster, the contrast agent saved will be even greater.

[0050] Therefore, this application utilizes a forward-pushing method with an OCT probe to collect signals reflected from the tissue interface. This minimizes contrast agent usage while ensuring a sufficient amount is used, avoiding insufficient contrast agent. Compared to the pull-back OCT imaging method, this saves approximately 50% of the contrast agent. Furthermore, by providing a catheter installation method that allows for forward-pushing OCT image acquisition, the forward-pushing operation can be performed directly from the proximal power source without interfering with the OCT probe's rotation and overall pushing performance, demonstrating strong versatility.

[0051] Based on the same inventive concept, this application also provides an image acquisition device corresponding to the image acquisition method. Since the principle of the device in this application is similar to that of the image acquisition method described above, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0052] Please see Figure 7 , Figure 7 This is a schematic diagram of a forward-push optical coherence tomography (OCT) image acquisition device provided in an embodiment of this application. Figure 7 As shown, the image acquisition device 700 includes: The determination module 710 is used to determine the blood flow velocity curve that changes with the cardiac cycle based on the first contrast image sequence before catheter insertion and release of contrast agent and the cardiac cycle timing signal. The correction module 720 is used to correct the blood flow velocity in the target vessel of the target patient based on the second contrast image of the catheter inserted to a designated position at the distal end of the lesion and the release of contrast agent is stopped, and to determine the unit release amount of contrast agent that matches the corrected blood flow velocity curve that changes with the cardiac cycle. Release module 730 is used to inject contrast agent according to the unit release amount of the contrast agent after the probe of the imaging catheter is moved to a designated position proximal to the lesion, and to monitor the imaging signal transmitted back by the probe. The control module 740 is used to control the probe to push forward until it reaches a designated position at the distal end of the lesion when it is determined from the imaging signal that the contrast agent covers the probe, and to acquire images during the advancement process.

[0053] Optionally, when determining the blood flow velocity curve that varies with the cardiac cycle based on the first contrast image sequence before catheter insertion and release of contrast agent and the cardiac cycle timing signal, the determining module 710 is used to: Before catheter insertion, contrast agent is injected into the blood vessel to acquire contrast images and record cardiac cycle signals, thereby obtaining the first contrast image sequence and cardiac cycle timing signal. Blood flow velocity is determined based on the interface movement data between contrast agent and blood in the first contrast image sequence; The blood flow velocity is correlated with the synchronously recorded cardiac cycle time-series signal to obtain a blood flow velocity curve that varies with the cardiac cycle.

[0054] Optionally, when the correction module 720 is used to correct the blood flow velocity in the target vessel of the target patient based on a second contrast image of the catheter inserted to a designated location distal to the lesion and the release of contrast agent stopped, and to determine a unit release amount of contrast agent that matches the corrected blood flow velocity curve varying with the cardiac cycle, the correction module 720 is used to: Stop releasing the contrast agent and acquire a second contrast image of the catheter at a designated location distal to the lesion; The projected length of the catheter is obtained based on the second contrast image; The intravascular volume with the catheter is calculated based on the projected length and cross-sectional area of ​​the catheter. The unit release amount of contrast agent is determined based on the intravascular volume with catheter and the blood flow velocity curve.

[0055] Optionally, when controlling the probe to push forward until it reaches a designated location distal to the lesion, the control module 740 is used to: The probe is pushed toward a designated location distal to the lesion at a propulsion speed not exceeding the lowest blood flow velocity in the blood flow velocity curve.

[0056] Optionally, when the control module 740 controls the probe to push forward until it reaches a designated position distal to the lesion, and performs image acquisition during the advancement process, the control module 740 is used to: The release time of the contrast agent is determined based on the probe's moving distance and the contrast agent's moving speed; wherein the release time is earlier than the time when the probe reaches the designated position at the distal end of the lesion; At the determined stop release time, the injection of the contrast agent is controlled to stop.

[0057] Optionally, the movement velocity of the contrast agent is the average diastolic blood flow velocity in the blood flow velocity curve or the average blood flow velocity throughout the cardiac cycle.

[0058] Optionally, the probe is installed in a push-type OCT image acquisition device. When the probe is pushed to a designated location at the distal end of the lesion, it moves along a guide rail inside an outer tube fixed in the push-type OCT image acquisition device. The outer tube is inserted into the vicinity of the stenosis through a catheter.

[0059] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 8 As shown, the electronic device 800 includes a processor 810, a memory 820, and a bus 830.

[0060] The memory 820 stores machine-readable instructions executable by the processor 810. When the electronic device 800 is running, the processor 810 and the memory 820 communicate via the bus 830. When the machine-readable instructions are executed by the processor 810, they can perform the operations described above. Figure 1 as well as Figure 5-6 The steps in the method embodiment shown are specifically implemented in the method embodiment and will not be repeated here.

[0061] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 as well as Figure 5-6 The steps in the method embodiment shown are specifically implemented in the method embodiment and will not be repeated here.

[0062] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0063] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0064] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0065] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0066] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0067] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for acquiring forward-push optical coherence tomography (OCT) images, characterized in that, The method includes: Based on the first contrast image sequence before catheter insertion and release of contrast agent, as well as the cardiac cycle timing signal, the blood flow velocity curve that varies with the cardiac cycle was determined. Based on the second angiographic image where the catheter is inserted to a designated location distal to the lesion and the release of contrast agent is stopped, the blood flow velocity in the target vessel of the target patient is corrected to determine the unit release amount of contrast agent that matches the corrected blood flow velocity curve that varies with the cardiac cycle. Once the imaging catheter probe is moved to the designated location proximal to the lesion, the contrast agent is injected according to the unit release dose, and the imaging signal transmitted back by the probe is monitored. When it is determined from the imaging signal that the contrast agent covers the probe, the probe is controlled to be pushed forward until it reaches the designated position at the distal end of the lesion, and image acquisition is performed during the advancement process.

2. The method according to claim 1, characterized in that, The step of determining the blood flow velocity curve that varies with the cardiac cycle based on the first contrast image sequence before catheter insertion and contrast agent release, and the cardiac cycle timing signal, includes: Before catheter insertion, contrast agent is injected into the blood vessel to acquire contrast images and record cardiac cycle signals, thereby obtaining the first contrast image sequence and cardiac cycle timing signal. Blood flow velocity is determined based on the interface movement data between contrast agent and blood in the first contrast image sequence; The blood flow velocity is correlated with the synchronously recorded cardiac cycle time-series signal to obtain a blood flow velocity curve that varies with the cardiac cycle.

3. The method according to claim 1, characterized in that, The step of correcting the blood flow velocity in the target vessel of the target patient based on a second angiographic image obtained by inserting the catheter to a designated location distal to the lesion and stopping the release of contrast agent, and determining a unit release amount of contrast agent that matches the corrected blood flow velocity curve varying with the cardiac cycle, includes: Stop releasing the contrast agent and acquire a second contrast image of the catheter at a designated location distal to the lesion; The projected length of the catheter is obtained based on the second contrast image; The intravascular volume with the catheter is calculated based on the projected length and cross-sectional area of ​​the catheter. The unit release amount of contrast agent is determined based on the intravascular volume with catheter and the blood flow velocity curve.

4. The method according to claim 1, characterized in that, The control of pushing the probe forward until it reaches the designated location distal to the lesion includes: The probe is pushed toward a designated location distal to the lesion at a propulsion speed not exceeding the lowest blood flow velocity in the blood flow velocity curve.

5. The method according to claim 1, characterized in that, The method further includes, while controlling the probe to move forward until it reaches a designated location distal to the lesion, and acquiring images during the advancement process: The release time of the contrast agent is determined based on the probe's moving distance and the contrast agent's moving speed; wherein the release time is earlier than the time when the probe reaches the designated position at the distal end of the lesion; At the determined stop release time, the injection of the contrast agent is controlled to stop.

6. The method according to claim 5, characterized in that, The velocity of the contrast agent is the average diastolic blood flow velocity in the blood flow velocity curve or the average blood flow velocity throughout the cardiac cycle.

7. The method according to claim 1, characterized in that, The probe is installed in a push-type OCT image acquisition device. When the probe is pushed to a designated location at the distal end of the lesion, it moves along a guide rail inside the outer tube fixed in the push-type OCT image acquisition device. The outer tube is inserted into the vicinity of the stenosis through a catheter.

8. A forward-push optical coherence tomography image acquisition device, characterized in that, Applied to the method of any one of claims 1-7, the image acquisition device comprises: The determination module is used to determine the blood flow velocity curve that varies with the cardiac cycle based on the first contrast image sequence before catheter insertion and release of contrast agent and the cardiac cycle timing signal; The calibration module is used to correct the blood flow velocity in the target vessel of the target patient based on the second angiographic image of the catheter inserted to a specified position at the distal end of the lesion and the release of contrast agent is stopped, and to determine the unit release amount of contrast agent that matches the corrected blood flow velocity curve that changes with the cardiac cycle. The release module is used to inject contrast agent according to the unit release amount after the probe of the imaging catheter is moved to a designated position proximal to the lesion, and to monitor the imaging signal transmitted back by the probe. The control module is used to control the probe to push forward until it reaches a designated position at the distal end of the lesion when it is determined from the imaging signal that the contrast agent covers the probe, and to acquire images during the advancement process.

9. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the memory via the bus, and the machine-readable instructions are executed by the processor to perform the steps of the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the steps of the method as described in any one of claims 1 to 7.

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