A method, system, and electronic device for determining blood flow velocity profiles

Abstract

This invention discloses a method, system, and electronic device for determining blood flow velocity profiles. The method includes performing ultrasound plane wave imaging on a target region of a blood vessel according to a preset angle sequence to obtain multiple ultrasound plane wave images at the current moment; performing motion compensation on multiple ultrasound plane wave images to be compensated, centered on a central ultrasound plane wave image, to obtain multiple compensated ultrasound plane wave images at the current moment; coherently combining the central ultrasound plane wave image and the multiple compensated ultrasound plane wave images to obtain a single frame of composite ultrasound image at the current moment; determining the blood flow velocity at different radial positions within the blood vessel lumen within a time interval of interest using speckle tracking; and constructing a blood flow velocity profile of the target region based on the blood flow velocities at different radial positions within the blood vessel lumen corresponding to the time interval of interest. This invention improves the accuracy of blood flow velocity profile determination by performing local motion compensation on multi-angle plane wave composite imaging.

Description

Technical Field

[0001] This invention relates to the field of blood flow velocity profile determination technology, and in particular to a method, system and electronic device for determining blood flow velocity profile. Background Technology

[0002] Determining blood flow velocity profiles generally relies on ultrasound imaging technology, which mainly includes two methods: conventional focused ultrasound (CFU) and plane wave ultrasound imaging. CFU transmits focused ultrasound signals line by line within a two-dimensional scanning plane, generating a single frame of ultrasound image from tens to hundreds of lines. This line-by-line scanning method results in a frame rate of only around 100 Hz, making it difficult to capture transient blood flow abnormalities caused by atherosclerosis. Plane wave ultrasound imaging, on the other hand, uses full-aperture plane wave transmission, generating a single frame of ultrasound image with a frame rate as high as 20,000 Hz. Because plane waves lack a focal point, the echo signal-to-noise ratio of a single plane wave is low, leading to poorer image quality.

[0003] To improve the imaging quality of single plane waves, a multi-angle ultrasonic plane wave composite imaging technique was proposed. This technique achieves plane wave emission with a certain tilt angle by changing the excitation time of the ultrasonic transducer array elements, obtaining multiple frames of plane wave echo signals from the same imaging region from multiple angles, and then coherently superimposing these multiple frames to obtain a composite image. Since the multi-angle plane wave coherent composite algorithm performs averaging processing on the multiple frames, it can effectively smooth noise, improve the signal-to-noise ratio, and generate a focused focal point, thus improving imaging quality. However, for high-speed blood flow, the speckle pattern in the time series of plane waves with different tilt angles continuously moves, resulting in motion artifacts in the directly composited image. This not only degrades the quality of the ultrasound image but also significantly interferes with the measurement of blood flow velocity. Summary of the Invention

[0004] The purpose of this invention is to provide a method, system, and electronic device for determining blood flow velocity profiles, which can perform local motion compensation for multi-angle plane wave composite imaging, thereby improving the accuracy of blood flow velocity profile determination.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] A method for determining blood flow velocity profiles includes:

[0007] Construct an empty set as a composite ultrasound image set;

[0008] Ultrasound plane wave imaging is performed on the target area of ​​the blood vessel according to a preset angle sequence to obtain multiple ultrasound plane wave images at the current moment; the preset angle sequence is an arithmetic sequence; the sum of all elements in the preset angle sequence is 0°; there are elements in the preset angle sequence that are 0°;

[0009] The ultrasonic plane wave image corresponding to the 0° plane wave at the current moment is determined as the central ultrasonic plane wave image;

[0010] The multiple ultrasound plane wave images at the current moment, excluding the central ultrasound plane wave image, are identified as ultrasound plane wave images to be compensated.

[0011] Using the central ultrasound plane wave image as the center, motion compensation is performed on multiple ultrasound plane wave images to be compensated, resulting in multiple compensated ultrasound plane wave images at the current moment.

[0012] The central ultrasound plane wave image and multiple compensated ultrasound plane wave images are coherently composited to obtain a composite ultrasound image at the current moment.

[0013] The current composite ultrasound image is added as an element to the composite ultrasound image set. The next moment is taken as the current moment, and the process returns to the step "perform ultrasound plane wave imaging on the target area of ​​the blood vessel according to the preset angle sequence to obtain multiple ultrasound plane wave images at the current moment" until the number of elements in the composite ultrasound image set reaches the preset element number threshold.

[0014] Based on the composite ultrasound image set, the blood flow velocity at different radial positions within the blood vessel lumen during the time interval of interest is determined using the speckle tracing method; the blood flow velocity in the target region during any time interval is obtained by processing two composite ultrasound images corresponding to the start and end times of the time interval using the speckle tracing method.

[0015] Based on the blood flow velocity at different radial positions within the blood vessel lumen corresponding to the time interval of interest, a blood flow velocity profile of the target region is constructed.

[0016] Optionally, the step of performing motion compensation on multiple ultrasound plane wave images to be compensated, centered on the central ultrasound plane wave image, to obtain multiple compensated ultrasound plane wave images at the current moment, includes:

[0017] The central ultrasound plane wave image and multiple ultrasound plane wave images to be compensated are arranged according to a preset angle sequence.

[0018] Determine any image direction as the target side; the image direction is either left or right.

[0019] Use the central ultrasound plane wave image as the reference image;

[0020] Let the number of iterations for the target-side image be j = 1;

[0021] The j-th ultrasound plane wave image to be compensated after determining the central ultrasound plane wave image is used as the comparison image.

[0022] Motion compensation is performed on the comparison image using the reference image to obtain the compensated ultrasonic plane wave image corresponding to the comparison image at the current moment;

[0023] Determine whether the number of iterations of the target-side image has reached the threshold for the number of iterations of the target-side image, and obtain a first determination result;

[0024] If the first judgment result is negative, then the comparison image is set as the reference image, the value of the iteration number j of the target side image is increased by 1, and the process returns to the step "the j-th ultrasound plane wave image to be compensated after determining the central ultrasound plane wave image is the comparison image".

[0025] If the first judgment result is yes, then determine whether to traverse all image directions to obtain the second judgment result;

[0026] If the second judgment result is negative, then update the target measurement and return to the step "set the central ultrasound plane wave image as the reference image";

[0027] If the second judgment result is yes, then the motion compensation is determined to be completed, and multiple compensated ultrasound plane wave images at the current moment are obtained.

[0028] Optionally, the step of using the reference image to perform motion compensation on the comparison image to obtain the compensated ultrasonic plane wave image corresponding to the comparison image at the current moment includes:

[0029] The region between the upper and lower pipe walls in the reference image is defined as the reference lumen.

[0030] The region between the upper and lower tube walls in the comparison images is defined as the comparison lumen.

[0031] The reference lumen is divided into n reference lumen layers on average; n is the preset number of layers.

[0032] The comparison lumen is divided into n comparison lumen layers on average;

[0033] Let the iteration number i = 1;

[0034] Determine any core block in the i-th reference lumen layer as the current core block;

[0035] The current search region is determined in the i-th comparison lumen layer based on the current kernel block; the current search region includes multiple currently matching blocks.

[0036] Based on the ultrasonic plane wave imaging data of the current kernel block and the ultrasonic plane wave imaging data of multiple current matching blocks, calculate the average sum of squared errors function value between the current kernel block and each current matching block;

[0037] The current matching block corresponding to the minimum average sum of squared errors function value is determined as the best matching block for the current kernel block;

[0038] The sum of the ultrasonic plane wave imaging data of the current core block and the ultrasonic plane wave imaging data of the best matching block of the current core block is used as the compensation result of the corresponding core block in the i-th comparison lumen layer.

[0039] Update the current kernel block and return to the step "Determine the current search region in the i-th comparison lumen layer based on the current kernel block" until all kernel blocks in the i-th reference lumen layer are traversed to obtain the compensation result of the i-th comparison lumen layer.

[0040] Determine whether the value of iteration number i has reached the preset number of division layers, and obtain the third judgment result;

[0041] If the third judgment result is negative, then the value of the iteration number i is increased by 1 and the process returns to the step "determine any core block in the i-th reference lumen layer as the current core block";

[0042] If the third judgment result is yes, then the compensated ultrasonic plane wave image corresponding to the comparison image at the current moment is determined according to the compensation result of the n-layer comparison lumen layer.

[0043] A blood flow velocity profile determination system, comprising:

[0044] The composite ultrasound image set construction module is used to construct an empty set into a composite ultrasound image set;

[0045] An ultrasound plane wave imaging module is used to perform ultrasound plane wave imaging on a target area of ​​a blood vessel according to a preset angle sequence, obtaining multiple ultrasound plane wave images at the current moment; the preset angle sequence is an arithmetic sequence; the sum of all elements in the preset angle sequence is 0°; and there are elements in the preset angle sequence that are 0°.

[0046] The central ultrasound plane wave image determination module is used to determine the ultrasound plane wave image corresponding to the 0° plane wave at the current time as the central ultrasound plane wave image.

[0047] The module for determining ultrasound plane wave images to be compensated is used to determine multiple ultrasound plane wave images other than the central ultrasound plane wave image at the current moment as ultrasound plane wave images to be compensated.

[0048] The motion compensation module is used to perform motion compensation on multiple ultrasound plane wave images to be compensated, with the central ultrasound plane wave image as the center, to obtain multiple compensated ultrasound plane wave images at the current moment.

[0049] The composite ultrasound image module is used to coherently composite the central ultrasound plane wave image and multiple compensated ultrasound plane wave images to obtain a composite ultrasound image of the current moment.

[0050] The current moment update module is used to add the current moment's composite ultrasound image as an element to the composite ultrasound image set, take the next moment as the current moment, and return to the step "perform ultrasound plane wave imaging on the target area of ​​the blood vessel according to the preset angle sequence to obtain multiple ultrasound plane wave images at the current moment" until the number of elements in the composite ultrasound image set reaches the preset element number threshold.

[0051] The blood flow velocity determination module is used to determine the blood flow velocity at different radial positions within the blood vessel lumen within the time interval of interest using the speckle tracing method based on the composite ultrasound image set; the blood flow velocity of the target region within any time interval is obtained by processing two frames of composite ultrasound images corresponding to the start and end times of the time interval using the speckle tracing method;

[0052] The blood flow velocity profile determination module is used to construct a blood flow velocity profile of the target region based on the blood flow velocity at different radial positions within the blood vessel lumen corresponding to the time interval of interest.

[0053] An electronic device includes a memory and a processor, the memory storing a computer program and the processor running the computer program to cause the electronic device to perform the method.

[0054] Optionally, the memory is a readable storage medium.

[0055] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0056] This invention provides a method, system, and electronic device for determining blood flow velocity profiles. The method involves performing ultrasound plane wave imaging on a target region of a blood vessel according to a preset angle sequence, obtaining multiple ultrasound plane wave images at the current moment. Motion compensation is then performed on the multiple ultrasound plane wave images to be compensated, centered on the central ultrasound plane wave image, to obtain multiple compensated ultrasound plane wave images at the current moment. The central ultrasound plane wave image and the multiple compensated ultrasound plane wave images are coherently composited to obtain a single frame of composite ultrasound image at the current moment. The composite ultrasound image set is updated, and the blood flow velocity at different radial positions within the blood vessel lumen within the time interval of interest is determined using speckle tracking. Based on the blood flow velocity at different radial positions within the blood vessel lumen corresponding to the time interval of interest, a blood flow velocity profile of the target region is constructed. This invention improves the accuracy of blood flow velocity profile determination by performing local motion compensation on multi-angle plane wave composite imaging. Attached Figure Description

[0057] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a flowchart of the blood flow velocity profile determination method in Embodiment 1 of the present invention;

[0059] Figure 2 This is a flowchart of the multi-angle plane wave compensation part in Embodiment 1 of the present invention;

[0060] Figure 3 This is a schematic diagram of multi-angle plane wave coherent composite imaging in Embodiment 1 of the present invention;

[0061] Figure 4 This is a schematic diagram of an ultrasonic plane wave radio frequency image in Embodiment 1 of the present invention;

[0062] Figure 5 This is a schematic diagram of the multi-angle plane wave compensation part in Embodiment 1 of the present invention;

[0063] Figure 6 This is a schematic diagram of a blood flow model in a specific example of Embodiment 1 of the present invention;

[0064] Figure 7 This is a comparison diagram of the blood flow velocity profile in Embodiment 1 of the present invention and the profile results of the traditional method. Detailed Implementation

[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] The purpose of this invention is to provide a method, system, and electronic device for determining blood flow velocity profiles, which can perform local motion compensation for multi-angle plane wave composite imaging, thereby improving the accuracy of blood flow velocity profile determination.

[0067] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0068] Currently, the following techniques are commonly used to determine blood flow velocity profiles:

[0069] I. Focused Ultrasound Algorithm

[0070] The focused ultrasound algorithm includes the following steps: First, the array elements within the effective aperture are continuously moved, generating one focused scan line each time. Then, based on multiple focused scan lines, ultrasound delay superposition beamforming echo signals are performed to generate one frame of ultrasound image. Since each generated scan line is focused, a high-resolution, high-signal-to-noise ratio, high-quality ultrasound image can be obtained. However, because it takes tens to hundreds of ultrasound signals to generate one frame of ultrasound image, the ultrasound image frame rate is very low.

[0071] II. Single Plane Wave Algorithm

[0072] The single plane wave algorithm includes the following steps: vertical transmission of a 0° plane wave using the full aperture, receiving the echo signal, and then beamforming the echo signal using an ultrasonic delay superposition method to generate a single frame of radio frequency (RF) signal. Since each plane wave transmission generates one RF signal frame, the pulse repetition frequency can reach up to 20,000 frames per second. However, due to the lack of a focal point, the resulting RF signal is highly susceptible to noise interference, resulting in a relatively low signal-to-noise ratio.

[0073] III. Coherent Composite Plane Wave Algorithm

[0074] The coherent composite plane wave algorithm includes the following steps: First, according to a preset deflection angle sequence, plane waves at multiple angles are cyclically transmitted through the full aperture, and echo signals are received throughout the aperture. Second, the echo signals are beamformed using an ultrasonic delay superposition method to generate plane wave radio frequency signals at multiple angles. Then, the tilted radio frequency signals are corrected according to the transmission angle. Finally, multiple frames of radio frequency signals within the deflection angle sequence are coherently superimposed to generate a single frame of composite radio frequency signal. Because of the coherent superposition of multi-angle plane waves, the target with the transmission focus is synthesized within the imaging region, solving the problem of poor imaging quality in single-plane wave algorithms. However, since the transmission of multi-angle plane waves is sequential, direct coherent superposition of multi-angle plane waves introduces motion artifacts caused by moving targets into the composite radio frequency signal.

[0075] IV. Multi-angle plane wave spatial motion compensation algorithm based on echo signal cross-correlation

[0076] The multi-angle plane wave spatial motion compensation algorithm based on echo signal cross-correlation includes the following steps: First, plane waves at multiple angles are emitted across the entire aperture according to a preset deflection angle sequence, and echo signals are received across the entire aperture; second, a reference signal is set in the multi-frame plane wave signals, and the offset of each line between the remaining frames and the reference signal is estimated using a cross-correlation algorithm; then, motion compensation is performed on each line of each frame signal based on the obtained offset; finally, the compensated signals are coherently composited to obtain the compensated multi-angle coherent plane wave. Because the offset between echo signals is corrected, compositing the corrected multi-angle plane waves improves the resolution of the composite image. However, since this compensation method compensates for a single echo signal as a whole, it ignores the differences in the motion speed of the imaging target at different spatial positions within the scanning plane, resulting in unsatisfactory artifact elimination.

[0077] V. Multi-angle plane wave time motion compensation algorithm based on Doppler signal autocorrelation

[0078] The multi-angle plane wave time motion compensation algorithm based on Doppler signal autocorrelation includes the following steps: First, plane waves at multiple angles are emitted across the entire aperture according to a preset deflection angle sequence, and echo signals are received across the entire aperture. Doppler signals are sampled at the same spatial location in each echo signal. Second, the obtained Doppler signals are divided into two equal segments, and their autocorrelation functions are calculated for each segment to determine the phase shift. Then, the average of the two phase shifts is taken as the phase difference for motion compensation. Finally, the velocity and offset of the scattering point at the current spatial location are calculated based on the phase difference to perform motion compensation, resulting in a compensated multi-angle coherent plane wave. Because motion compensation is performed on all spatial locations within the two-dimensional scanning plane, the spatial positional differences of the scattering object's motion are considered, improving the effect of motion artifact elimination. However, since this compensation method is based on the premise that the imaging target is in uniform linear motion, it is not suitable for blood flow imaging with other complex motion states, thus limiting its applicability.

[0079] Existing algorithms for motion-compensated ultrasound blood flow imaging mainly include: focused ultrasound algorithm, single plane wave algorithm, coherent composite plane wave algorithm, multi-angle plane wave spatial motion compensation algorithm based on echo signal cross-correlation, and multi-angle plane wave temporal motion compensation algorithm based on Doppler signal autocorrelation. Focused ultrasound imaging can be achieved by delaying and summing the transmitted and received signals. The main drawback of focused ultrasound algorithms is the low frame rate, requiring tens to hundreds of lines of ultrasound signals to generate a single frame. To overcome this drawback, the single plane wave algorithm was proposed. This algorithm generates one frame of radio frequency signal per plane wave transmission, resulting in a very high frame rate. However, it lacks a transmission focus, has a low signal-to-noise ratio, and the resulting radio frequency signal is susceptible to noise interference. To further overcome this drawback, the coherent composite plane wave algorithm was proposed. This algorithm generates a synthetic focus by superimposing plane waves from multiple angles, thereby improving image quality. However, in plane wave time series from multiple angles, blood flow speckle is constantly moving, and direct composite imaging leads to motion artifacts in the composite image, severely interfering with the accurate measurement of blood flow velocity. To overcome the main drawbacks of coherent composite plane wave algorithms, a multi-angle plane wave spatial motion compensation algorithm based on echo signal cross-correlation is proposed. This algorithm eliminates motion artifacts by performing motion compensation on each echo signal line. However, it compensates for each echo signal line as a whole, ignoring the differences in the motion velocity of the imaging target at different spatial positions within the scanning plane, resulting in inadequate motion artifact elimination. To overcome the main drawbacks of the echo signal cross-correlation-based multi-angle plane wave spatial motion compensation algorithm, a multi-angle plane wave temporal motion compensation algorithm based on Doppler signal autocorrelation is proposed. This algorithm performs motion compensation on all spatial positions within the two-dimensional scanning plane one by one, considering the spatial positional differences of the scatterer motion, thus improving the effect of motion artifact elimination. However, since the multi-angle plane wave time motion compensation algorithm based on Doppler signal autocorrelation is based on the premise that the imaging target is in uniform linear motion, it is not applicable to blood flow imaging in other complex motion states. The method has harsh applicable conditions and limited applicability.

[0080] To address the main shortcomings of the five existing technologies mentioned above, this invention proposes a local motion compensation and blood flow imaging technique for multi-angle plane wave composite imaging. This technique first performs motion compensation on adjacent angle ultrasound plane waves centered at 0 degrees before coherent composite imaging of the multi-angle plane waves. Then, it performs coherent composite imaging of the compensated multi-angle plane waves. The main advantages of this invention are that by performing local motion compensation on adjacent angle plane waves, it avoids incomplete artifact elimination caused by spatial position differences. Furthermore, it eliminates the requirement for the imaging target to undergo uniform linear motion, supports blood flow imaging in various complex motion states, reduces motion artifacts generated by blood flow during direct coherent composite imaging of multi-angle plane waves, improves the ultrasound plane wave composite imaging effect on moving targets, enhances blood flow imaging quality, and increases the accuracy of blood flow velocity measurement. Specific implementation schemes are described in the following embodiments.

[0081] Example 1

[0082] like Figure 1 and Figure 3 As shown, this embodiment provides a method for determining blood flow velocity profiles, including:

[0083] Step 101: Construct an empty set as a composite ultrasound image set.

[0084] Step 102: Perform ultrasound plane wave imaging on the target area of ​​the blood vessel according to the preset angle sequence to obtain multiple ultrasound plane wave images at the current moment. The preset angle sequence is an arithmetic progression. The sum of all elements in the preset angle sequence is 0°. There are elements in the preset angle sequence that are 0°.

[0085] Step 103: Determine the ultrasonic plane wave image corresponding to the 0° plane wave at the current time as the central ultrasonic plane wave image.

[0086] Step 104: Determine the multiple ultrasound plane wave images other than the central ultrasound plane wave image at the current time as ultrasound plane wave images to be compensated.

[0087] Step 105: Using the central ultrasound plane wave image as the center, perform motion compensation on multiple ultrasound plane wave images to be compensated to obtain multiple compensated ultrasound plane wave images at the current time.

[0088] Step 106: Coherently composite the central ultrasound plane wave image and multiple compensated ultrasound plane wave images to obtain a composite ultrasound image of the current moment.

[0089] Step 107: Add the current composite ultrasound image as an element to the composite ultrasound image set, take the next moment as the current moment, and return to step 102 until the number of elements in the composite ultrasound image set reaches the preset element number threshold.

[0090] Step 108: Based on the composite ultrasound image set, determine the blood flow velocity at different radial positions within the blood vessel lumen during the time interval of interest using the speckle tracing method. The blood flow velocity in the target region during any time interval is obtained by processing two composite ultrasound images corresponding to the start and end times of the time interval using the speckle tracing method.

[0091] Step 109: Construct a blood flow velocity profile of the target region based on the blood flow velocity at different radial positions within the blood vessel lumen corresponding to the time interval of interest.

[0092] Step 105 includes:

[0093] Step 1051: Arrange the central ultrasound plane wave image and multiple ultrasound plane wave images to be compensated according to a preset angle sequence.

[0094] Step 1052: Determine any image orientation as the target side. The image orientation is either left or right.

[0095] Step 1053: Use the central ultrasound plane wave image as the reference image.

[0096] Step 1054: Set the number of iterations for the target side image to j = 1.

[0097] Step 1055: Determine the j-th ultrasound plane wave image to be compensated after the central ultrasound plane wave image as the comparison image.

[0098] Step 1056: Use the reference image to perform motion compensation on the comparison image to obtain the compensated ultrasonic plane wave image corresponding to the comparison image at the current moment.

[0099] Step 1057: Determine whether the number of iterations of the target image has reached the threshold for the number of iterations of the target image, and obtain the first determination result. If the first determination result is negative, proceed to step 1058; if the first determination result is positive, proceed to step 1059.

[0100] Step 1058: Let the comparison image be the reference image, increment the value of the iteration number j of the target side image by 1, and return to step 1055.

[0101] Step 1059: Determine whether to traverse all image directions to obtain a second determination result. If the second determination result is negative, proceed to step 10510; if the second determination result is positive, proceed to step 10511.

[0102] Step 10510: Update the target measurement and return to step 1053.

[0103] Step 10511: Determine that motion compensation has ended and obtain multiple compensated ultrasound plane wave images at the current moment.

[0104] like Figure 2Step 1056 includes:

[0105] Step 1056-1: Determine the area between the upper and lower pipe walls in the reference image as the reference lumen.

[0106] Step 1056-2: Determine the area between the upper and lower tube walls in the comparison image as the comparison lumen.

[0107] Step 1056-3: Divide the reference lumen into n reference lumen layers on average. n is the preset number of layers.

[0108] Step 1056-4: Divide the comparison lumen into n comparison lumen layers on average.

[0109] Step 1056-5: Let the iteration number i = 1.

[0110] Step 1056-6: Determine any core block in the i-th reference lumen layer as the current core block.

[0111] Step 1056-7: Determine the current search region in the i-th layer comparison lumen based on the current core block. The current search region includes multiple currently matching blocks.

[0112] Step 1056-8: Based on the ultrasonic plane wave imaging data of the current core block and the ultrasonic plane wave imaging data of multiple current matching blocks, calculate the average sum of squared errors function value between the current core block and each current matching block.

[0113] Step 1056-9: Determine the current matching block corresponding to the minimum average squared error function value as the best matching block for the current kernel block.

[0114] Step 1056-10: The sum of the ultrasonic plane wave imaging data of the current core block and the ultrasonic plane wave imaging data of the best matching block of the current core block is used as the compensation result of the corresponding core block in the i-th comparison lumen layer.

[0115] Step 1056-11: Update the current core block and return to step 1056-7 until all core blocks in the i-th reference lumen layer are traversed to obtain the compensation result of the i-th comparison lumen layer.

[0116] Step 1056-12: Determine whether the value of the iteration number i has reached the preset number of division layers, and obtain the third judgment result. If the third judgment result is negative, proceed to step 1056-13; if the third judgment result is positive, proceed to step 1056-14.

[0117] Step 1056-13: Increment the value of iteration number i by 1 and return to step 1056-6.

[0118] Step 1056-14: Determine the compensated ultrasonic plane wave image corresponding to the comparison image at the current moment based on the compensation results of the n-layer comparison lumen layer.

[0119] Specifically, the method for determining blood flow velocity profiles provided by this invention includes:

[0120] 1) Set the transmission frequency f and sampling frequency f of the ultrasonic transducer. s The number of array elements, m.

[0121] 2) Select the region of interest for blood flow imaging and set the imaging width w and depth d of the ultrasound plane wave.

[0122] The lateral extent of the imaging region of interest is χ a ~χ b The horizontal center is χ=(χ b -χ a )÷2. The vertical range is y. a ~y b The longitudinal center is y = (y b -y a )÷2.

[0123] 3) Set the number of deflection angles N and the angle interval Δθ for ultrasonic plane wave imaging, and ensure that the set deflection angles are symmetrical on both sides with 0° as the center.

[0124] When the number of deflection angles N is odd, the deflection angles are as follows:

[0125]

[0126] When the number of deflection angles N is even, N+1 is automatically executed to make the number of deflection angles odd. The deflection angles are as follows:

[0127]

[0128] Where 1≤i≤N is the deflection angle sequence number, and Δθ is the angle interval.

[0129] 4) Perform ultrasonic plane wave imaging on each deflection angle determined in step 3).

[0130] 5) Using the 0° plane wave as the center, perform local motion compensation on the plane waves at the left and right adjacent angles respectively.

[0131] 6) Following step 5), perform motion compensation sequentially on the plane waves at each angle to the right of the 0° plane wave: the first time for α i °=0° Ultrasonic plane wave and α i+1 Motion compensation using ultrasonic plane waves to extract α i ° Ultrasonic plane wave and α i+1RF data of ultrasonic plane waves, second time for α i+1 ° Ultrasonic plane wave and α i+2 Motion compensation is performed on the ultrasonic plane wave, and the corresponding ultrasonic plane wave data is extracted. Compensation is then performed c1 times sequentially. The c1th compensation step... and Ultrasonic plane waves are compensated, where c1≥1, i+c1≤N (N is an odd number), and i+c1≤N+1 (N is an even number).

[0132] 7) Similar to step 6), perform motion compensation sequentially for the plane waves at each angle to the left of the 0° plane wave: the first time for α i °=0° Ultrasonic plane wave and α i-1 Motion compensation using ultrasonic plane waves to extract α i ° Ultrasonic plane wave and α i-1 RF data of ultrasonic plane waves. Second measurement of α... i-1 ° Ultrasonic plane wave and α i-2 Motion compensation is performed on the ultrasonic plane wave, and the corresponding ultrasonic plane wave data is extracted. Compensation is then performed c2 times sequentially, with the c2th time... and Ultrasonic plane wave compensation is performed, where 1≤c2≤i-1. (Steps 6 and 7 are not in any particular order).

[0133] 8) Based on the RF data obtained in step 6) or 7), set its corresponding value as the reference data RF. refe Comparison data RF com .

[0134] 9) In reference data RF refe Comparison data RF com Find the pipe wall and lumen information, divide it into n layers from the upper pipe wall to the lower pipe wall, and calculate the height of each layer.

[0135]

[0136] Among them, y rf-a and y rf-b These are the coordinates of the upper and lower pipe walls in the RF data, H. rf H represents the height of each layer in the RF data, H represents the height of each layer in the actual imaging, and r is the blood vessel radius. Ensure:

[0137] H×n≥2r

[0138] 10) In reference data RF refe Set a set of core block data S in the i-th layer kernel S kernel The dimensions are a×b, a>1 max I maxb is the distance traveled at maximum flow velocity; b ≥ H rf In comparing data RF com Set the corresponding search area S in the middle. search S search The dimensions are c×d, c≥a, d≥b, in the search region S search Define matching block S in match S match The dimensions are a × b.

[0139]

[0140] Among them, S kernel For core block data information, S search For the set search area information, S match V is the information for the matching blocks determined in the search area. max ν is the maximum velocity of blood flow in the blood vessel, 1≤i≤n. f is the transmission frequency of the ultrasound transducer.

[0141] 11) Calculate S kernel and S match The mean squared error function MSD is used to construct the mean squared error function matrix MMSD.

[0142]

[0143] Where a and b are the size of the nucleus block. i and j are the row and column indices of the mean squared error function matrix (i <= n; n is the number of vascular lumen layers); j <= d - b + 1; d is the x-axis length of the preset search area size, and b is the x-axis length of the preset nucleus block size; MSD(i,j) represents the value at the i-th row and j-th column of the mean squared error function matrix, where the rows of the mean squared error function matrix represent the number of vascular lumen layers, and the columns represent the number of matching blocks that can be found in each layer of the current nucleus block; S kernel (i+k-1,j+m-1) represents the information of the pixel at position i+k-1 x-coordinate and j+m-1 y-coordinate in the kernel block; S match '(k,m) represents the information of the pixel at coordinate k and coordinate m in the current matching block, where S... kernel and S match The dimensions are all the same, a×b as determined above; k and m are the row index and column index, respectively. All information within the core block has been processed using the sum of squared errors formula. The essence of the average sum of squared errors formula in this invention is as follows: for each piece of information within the core block size, the error is calculated and squared for each piece of information in its corresponding matching block. Finally, all the squared errors are summed and averaged over the whole.

[0144] 12) Determine the best matching block S corresponding to each kernel block based on the minimum value of the mean squared error function matrix. optimum-march .

[0145] 13) Find S in step 12). optimum-match Information directly related to the corresponding S kernel Information addition to achieve α i+c ° Ultrasonic plane wave or α i-c ° Compensation of the i-th layer in ultrasonic plane waves.

[0146] 14) Repeat steps 10)-13) n times until α is reduced. i+c ° Ultrasonic plane wave or α i-c ° In ultrasonic plane waves, all n layers of the lumen are fully compensated.

[0147] 15) Repeat steps 6)-14)c1+c2 times to compensate for all plane waves except for the 0° plane wave.

[0148] 16) Perform multi-angle plane wave coherent composite of the compensated c1+c2 plane wave and 0° plane wave ultrasound images to obtain the composite ultrasound image.

[0149] 17) Select the two composite ultrasound images to perform speckle tracking to calculate the blood flow velocity in the target area.

[0150] 18) Combine all the obtained velocities within the target area to establish a blood flow velocity profile. The invention will now be specifically described using a cylindrical blood vessel located 25 mm subcutaneously, with a lumen radius of R = 3.5 mm and a vessel tilt angle of 0° as an example.

[0151] 1) Establish attachment Figure 6 The blood flow model shown.

[0152] The cylindrical blood vessel is located 25 mm subcutaneously, with a lumen radius of R = 3.5 mm, a vessel tilt angle of 0°, and a maximum central velocity of v. max =1.67 m / s, then the blood flow velocity profile from the upper wall to the lower wall is:

[0153]

[0154] Where 1≤r≤R.

[0155] 2) Set the ultrasonic transducer's transmission frequency f = 10000 Hz and sampling frequency f s =10MHz and the number of array elements m=128.

[0156] 3) Select the region of interest for blood flow imaging, and set the imaging width w = 38 mm and depth d = 40 mm for the ultrasound plane wave.

[0157] The lateral extent of the region of interest in blood flow imaging is x a = -19mm to χ b =19mm, the horizontal center is χ=(χ b -χ a ) ÷ 2 = 0 mm. The longitudinal range is y. a =0mm to y b =40mm, longitudinal center is y=(y b -ya ) ÷2=20mm.

[0158] 4) Set the number of deflection angles N and the angle interval Δθ for ultrasonic plane wave imaging to ensure that the deflection angles are symmetrical on both sides with 0° as the center.

[0159] When the number of deflection angles N = 11 and the angle interval Δθ = 1°, the deflection angle α is calculated by substituting into the following formula. i :

[0160]

[0161] Where 1≤i≤N is the deflection angle sequence number, and Δθ is the angle interval.

[0162] Then α1°=-5°, α2°=-4°, α3°=-3°, α4°=-2°, α5°=-1°, α6°=0°, α7°=1°, α8°=2°, α9°=3°, α 10 ° = 4°, α 11 ° = 5°, in a specific example α1° = 1°

[0163] 5) Perform ultrasonic plane wave imaging on each deflection angle determined in step 4).

[0164] 6) Using the 0° plane wave as the center, perform local motion compensation on the plane waves at the left and right adjacent angles respectively.

[0165] 7) Following step 6), perform motion compensation sequentially on the plane waves at each angle to the right of the 0° plane wave: the first time for α i °=α6°=0° Ultrasonic plane wave and α i+1 °=α 6+1 Motion compensation was performed using an ultrasonic plane wave at ° = 1° to extract α. i °=α6°=0° Ultrasonic plane wave and α i+1 °=α 6+1 RF data of ultrasonic plane wave at ° = 1°, second time for α i+1 °=α 6+1 ° = 1° ultrasonic plane wave and α i+2 °=α 6+2Motion compensation was performed on an ultrasonic plane wave with a radius of 2°. Corresponding ultrasonic plane wave data was extracted, and compensation was performed sequentially for c1 = 5 times. The c1 = 5th compensation step... and Ultrasonic plane waves are compensated, where c1≥1, i+c1≤N (N is an odd number), and i+c1≤N+1 (N is an even number).

[0166] 8) Similar to step 7), perform motion compensation sequentially for the plane waves at each angle to the left of the 0° plane wave: the first time for α i °=α6°=0° Ultrasonic plane wave and α i-1 °=α 6-1 Motion compensation was performed using an ultrasonic plane wave at ° = -1° to extract α. i °=α6°=0° Ultrasonic plane wave and α i-1 °=α 6-1 RF data for ultrasonic plane waves at ° = -1°. Second measurement of α. i-1 °=α 6-1 °=-1° Ultrasonic plane wave and α i-2 °=α 6-2 Motion compensation was performed on an ultrasonic plane wave at ° = -2°, and the corresponding ultrasonic plane wave data was extracted. This compensation was repeated c2 = 5 times. The c2 = 5th compensation step... and Ultrasonic plane wave compensation is performed, where 1 ≤ c2 ≤ i-1 = 6-1. (Steps 6 and 7 are not in any particular order.)

[0167] 9) Based on the RF data obtained in step 6) or 7), set its corresponding value as the reference data RF. refe Comparison data RF com In the example, motion compensation is first performed on the plane waves at various angles to the right of the 0° plane wave, and α is extracted. i °=α6°=0° Ultrasonic plane wave and α i-1 °=α 6-1 The radio frequency signal of an ultrasonic plane wave with a temperature of -1° is used as the reference data RF. refe Comparison data RF com .

[0168] 10) In reference data RF refe Comparison data RF com Find the pipe wall and lumen information, as shown in the attached image. Figure 4 As shown, the pipe is divided into n=90 layers from the upper pipe wall to the lower pipe wall, and the height of each layer is calculated.

[0169]

[0170] Among them, y rf-a =2090 and y rf-b=2900 is the coordinate of the upper and lower pipe walls in the RF data, H rf H is the height of each layer in the RF data, H is the height of each layer in the actual imaging, and r is the radius of the blood vessel.

[0171] Then H rf =9, H=0.0778mm, satisfying H×n=0.0778×90=7.002≥2r=7mm

[0172] 11) In reference data RF refe Set a set of core block data S in the i-th layer kernel S kernel The dimensions are a×b, a>l max b≥H rf In comparing data RF com Set the corresponding search area S in the middle. search S search The dimensions are c×d, c≥a, d≥b, in the search region S search Define matching block S in match S match The size is a×b. 1≤i≤90.

[0173]

[0174] Among them, S kernel For core block data information, S search For the set search area information, S match For matching block information in the search area, V max Let a be the maximum velocity of blood flow in the blood vessel. In this specific example, a = 20, b = 10, c = 50, and d = 10.

[0175] 12) Calculate S kernel and S match The mean squared error function (MSD) is used to construct the mean squared error function matrix MMSD.

[0176]

[0177] Where a and b are the core block sizes.

[0178] 13) Determine the best matching block S corresponding to each kernel block based on the minimum value of the mean square error function matrix. optimum-match ,like Figure 5 As shown.

[0179] 14) Find S in step 13). optimum-match The information is directly added to the corresponding S kernel The information is used to achieve compensation of the i-th layer in a 1° ultrasonic plane wave.

[0180] 15) Repeat steps 11)-14) n=90 times until all n=90 layers of the lumen in the 1° ultrasonic plane wave are fully compensated.

[0181] 16) Repeat steps 7)-15) c1+c2=10 times to compensate for all plane waves except for the 0° plane wave.

[0182] 17) The compensated c1+c2 = 10 plane wave ultrasound images and the 0° plane wave ultrasound images were combined using multi-angle plane wave coherent composite to obtain the composite ultrasound image. The results are as follows: Figure 3 As shown.

[0183] 18) Select the two composite ultrasound images and perform speckle tracking to calculate the blood flow velocity in the target area.

[0184] 19) Combine all the obtained velocities within the target area to construct a blood flow velocity profile. The results are shown in the appendix. Figure 6 As shown.

[0185] Specifically, in this embodiment, due to local motion compensation between adjacent angular plane waves, blood flow motion artifacts in the coherent composite imaging region are removed, solving the problem of motion artifacts in coherent composite plane wave imaging technology. Because blood flow motion artifacts are removed during plane wave composite imaging, the ultrasonic plane wave composite imaging effect of moving targets is improved, enhancing blood flow imaging quality and blood flow velocity measurement accuracy. Utilizing adjacent angular plane waves for local motion compensation not only ensures the spatiotemporal consistency of the signal but also supports more complex imaging target motion states.

[0186] Example 2

[0187] In order to execute the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a blood flow velocity profile determination system is provided below, including:

[0188] The composite ultrasound image set construction module is used to construct an empty set into a composite ultrasound image set.

[0189] The ultrasound plane wave imaging module is used to perform ultrasound plane wave imaging on the target area of ​​the blood vessel according to a preset angle sequence, obtaining multiple ultrasound plane wave images at the current moment. The preset angle sequence is an arithmetic progression. The sum of all elements in the preset angle sequence is 0°. There are elements in the preset angle sequence that are 0°.

[0190] The central ultrasound plane wave image determination module is used to determine the ultrasound plane wave image corresponding to the 0° plane wave at the current time as the central ultrasound plane wave image.

[0191] The module for determining ultrasound plane wave images to be compensated is used to determine multiple ultrasound plane wave images other than the central ultrasound plane wave image at the current moment as ultrasound plane wave images to be compensated.

[0192] The motion compensation module is used to perform motion compensation on multiple ultrasound plane wave images to be compensated, with the central ultrasound plane wave image as the center, to obtain multiple compensated ultrasound plane wave images at the current moment.

[0193] The composite ultrasound image module is used to coherently composite the central ultrasound plane wave image and multiple compensated ultrasound plane wave images to obtain a composite ultrasound image of the current moment.

[0194] The current time update module is used to add the current time composite ultrasound image as an element to the composite ultrasound image set, take the next time as the current time, and return to the step "perform ultrasound plane wave imaging on the target area of ​​the blood vessel according to the preset angle sequence to obtain multiple ultrasound plane wave images at the current time" until the number of elements in the composite ultrasound image set reaches the preset element number threshold.

[0195] The blood flow velocity determination module is used to determine the blood flow velocity at different radial locations within the blood vessel lumen during a time interval of interest, based on a composite ultrasound image set and using speckle tracing. The blood flow velocity of the target region within any time interval is obtained by processing two frames of composite ultrasound images corresponding to the start and end times of the time interval using speckle tracing.

[0196] The blood flow velocity profile determination module is used to construct a blood flow velocity profile of the target region based on the blood flow velocity at different radial positions within the blood vessel lumen corresponding to the time interval of interest.

[0197] Example 3

[0198] This embodiment provides an electronic device, characterized in that it includes a memory and a processor. The memory stores a computer program, and the processor runs the computer program to cause the electronic device to perform the method described in Embodiment 1. The memory is a readable storage medium.

[0199] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0200] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A blood flow velocity profile determination method, characterized by, The method comprises the following steps: Constructing an empty set as a composite ultrasound image set; Performing ultrasound plane wave imaging on a target region of a blood vessel according to a preset angle sequence to obtain multiple ultrasound plane wave images at a current time; the preset angle sequence is an arithmetic sequence; the sum of all elements in the preset angle sequence is 0°; there is an element of 0° in the preset angle sequence; Determining an ultrasound plane wave image corresponding to 0° plane wave at the current time as a center ultrasound plane wave image; Determining the multiple ultrasound plane wave images at the current time except the center ultrasound plane wave image as multiple to-be-compensated ultrasound plane wave images; Performing motion compensation on the multiple to-be-compensated ultrasound plane wave images with the center ultrasound plane wave image as the center to obtain multiple compensated ultrasound plane wave images at the current time; Performing coherent compounding on the center ultrasound plane wave image and the multiple compensated ultrasound plane wave images to obtain one frame of composite ultrasound image at the current time; Adding the composite ultrasound image at the current time as an element to the composite ultrasound image set, taking the next time as the current time, and returning to the step of performing ultrasound plane wave imaging on the target region of the blood vessel according to the preset angle sequence to obtain multiple ultrasound plane wave images at the current time until the number of elements in the composite ultrasound image set reaches a preset element number threshold; Determining blood flow velocities of different radial positions of a blood vessel lumen in a time interval of interest according to the composite ultrasound image set by using a speckle tracking method; the blood flow velocity of the target region in any time interval is obtained by processing two frames of composite ultrasound images corresponding to the start and end times of the time interval by using the speckle tracking method; Constructing a blood flow velocity profile of the target region according to the blood flow velocities of different radial positions of the blood vessel lumen corresponding to the time interval of interest; When performing motion compensation on the multiple to-be-compensated ultrasound plane wave images with the center ultrasound plane wave image as the center, performing motion compensation on a comparison image by using a reference image to obtain a compensated ultrasound plane wave image corresponding to the comparison image at the current time, comprising the following steps: Determining a region between an upper vessel wall and a lower vessel wall in the reference image as a reference lumen; Determining a region between an upper vessel wall and a lower vessel wall in the comparison image as a comparison lumen; Dividing the reference lumen into n layers of reference lumen layers on average; n is a preset number of division layers; Dividing the comparison lumen into n layers of comparison lumen layers on average; Setting an iteration number i to 1; Determining any kernel block in the i-th layer of reference lumen layers as a current kernel block; Determining a current search region in the i-th layer of comparison lumen layers according to the current kernel block; the current search region comprises multiple current matching blocks; Calculating average error sum of squares function values of the current kernel block and each current matching block according to ultrasound plane wave imaging data of the current kernel block and ultrasound plane wave imaging data of the multiple current matching blocks, respectively; Determining a current matching block corresponding to the minimum average error sum of squares function value as the best matching block of the current kernel block; Taking a sum of ultrasound plane wave imaging data of the current kernel block and ultrasound plane wave imaging data of the best matching block of the current kernel block as a compensation result of a corresponding kernel block in the i-th layer of comparison lumen layers. updating the current kernel and returning to the step of "determining a current search region in the i-th layer comparison lumen layer according to the current kernel" until all the kernels in the i-th layer reference lumen layer are traversed, obtaining the compensation result of the i-th layer comparison lumen layer; determining whether the value of the iteration number i reaches the preset number of division layers, obtaining a third determination result; if the third determination result is no, increasing the value of the iteration number i by 1 and returning to the step of "determining any kernel in the i-th layer reference lumen layer as the current kernel"; if the third determination result is yes, determining the compensated ultrasonic plane wave image corresponding to the comparison image at the current moment according to the compensation result of the n-th layer comparison lumen layer.

2. A blood flow velocity profile determination method according to claim 1, characterized by, the motion compensation of the plurality of to-be-compensated ultrasonic plane wave images with the center ultrasonic plane wave image as the center to obtain the plurality of compensated ultrasonic plane wave images at the current moment, comprising: arranging the center ultrasonic plane wave image and the plurality of to-be-compensated ultrasonic plane wave images according to a preset angle sequence; determining any image direction as a target side; the image direction is a left side or a right side; taking the center ultrasonic plane wave image as a reference image; taking the iteration number j of the target side image as 1; determining the j-th to-be-compensated ultrasonic plane wave image after the center ultrasonic plane wave image as a comparison image; performing motion compensation on the comparison image by using the reference image to obtain the compensated ultrasonic plane wave image corresponding to the comparison image at the current moment; determining whether the iteration number of the target side image reaches a target side image iteration number threshold, obtaining a first determination result; if the first determination result is no, taking the comparison image as the reference image, increasing the value of the iteration number j of the target side image by 1, and returning to the step of "determining the j-th to-be-compensated ultrasonic plane wave image after the center ultrasonic plane wave image as a comparison image"; if the first determination result is yes, determining whether all the image directions are traversed, obtaining a second determination result; if the second determination result is no, updating the target and returning to the step of "taking the center ultrasonic plane wave image as a reference image"; if the second determination result is yes, determining that the motion compensation is completed, and obtaining the plurality of compensated ultrasonic plane wave images at the current moment.

3. A blood flow velocity profile determination system characterized by, The blood flow velocity profile determination system applies the blood flow velocity profile determination method in any one of claims 1-2, and the blood flow velocity profile determination system comprises: a composite ultrasonic image set construction module, configured to construct an empty set as a composite ultrasonic image set; an ultrasonic plane wave imaging module, configured to perform ultrasonic plane wave imaging on a target region of a blood vessel according to a preset angle sequence to obtain a plurality of ultrasonic plane wave images at the current moment; the preset angle sequence is an arithmetic sequence; all elements in the preset angle sequence add up to 0°; there is an element of 0° in the preset angle sequence; a center ultrasonic plane wave image determination module, configured to determine an ultrasonic plane wave image corresponding to a 0° plane wave at the current moment as a center ultrasonic plane wave image; a to-be-compensated ultrasonic plane wave image determination module, configured to determine the plurality of ultrasonic plane wave images at the current moment except the center ultrasonic plane wave image as to-be-compensated ultrasonic plane wave images; and a motion compensation module, configured to perform motion compensation on the plurality of to-be-compensated ultrasonic plane wave images with the center ultrasonic plane wave image as the center to obtain the plurality of compensated ultrasonic plane wave images at the current moment. a motion compensation module, configured to perform motion compensation on a plurality of to-be-compensated ultrasonic plane wave images centered on a center ultrasonic plane wave image to obtain a plurality of compensated ultrasonic plane wave images at a current time; a composite ultrasonic image module, configured to perform coherent compounding on the center ultrasonic plane wave image and the plurality of compensated ultrasonic plane wave images to obtain one frame of composite ultrasonic image at the current time; a current time updating module, configured to add the composite ultrasonic image at the current time as an element to the composite ultrasonic image set, take a next time as the current time, and return to the step of "performing ultrasonic plane wave imaging on a target region of a blood vessel according to a preset angle sequence to obtain a plurality of ultrasonic plane wave images at a current time" until the number of elements in the composite ultrasonic image set reaches a preset element number threshold; a blood flow velocity determination module, configured to determine blood flow velocities of different radial positions of a blood vessel lumen in a time interval of interest according to the composite ultrasonic image set by using a speckle tracking method; and the blood flow velocity of the target region in any time interval is obtained by processing two frames of composite ultrasonic images corresponding to the start and end times of the time interval by using the speckle tracking method; a blood flow velocity profile determination module, configured to construct a blood flow velocity profile of the target region according to the blood flow velocities of different radial positions of the blood vessel lumen corresponding to the time interval of interest.

4. An electronic device, comprising: The electronic device includes a memory and a processor. The memory is configured to store a computer program. The processor is configured to execute the computer program to enable the electronic device to perform the method in any one of claims 1 to 2.

5. An electronic device according to claim 4, wherein, The memory is a readable storage medium.

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