Method and apparatus for determining blood flow velocity in a blood vessel

Abstract

This application provides a method and apparatus for determining blood flow velocity in a blood vessel, comprising: acquiring an initial contrast image and a target contrast image after injecting a contrast agent; comparing the initial contrast image and the target contrast image to determine the length of the blood vessel through which the contrast agent flows; determining the uniformity of the contrast agent in the main vessel region and / or the visualization of microvessels in the background region of the target contrast image based on the contrast agent concentration in the target contrast image; correcting the blood vessel length based on the uniformity of the contrast agent and / or the visualization of microvessels to obtain a corrected blood vessel length; and determining the blood flow velocity based on the corrected blood vessel length. This reduces calculation errors caused by the imaging angle of the contrast image, the shape of the blood vessel, or blood vessel bifurcation, thereby improving the accuracy of blood flow velocity assessment.

Description

Technical Field

[0001] This application relates to the field of medical image processing technology, and in particular to a method and apparatus for determining blood flow velocity in blood vessels. Background Technology

[0002] Currently, the most commonly used method for determining vascular flow velocity in contrast-enhanced functional assessment techniques is the TIMI frame-by-frame method. This method calculates blood flow velocity by observing the length of the blood vessel through which the contrast agent flows in the contrast image and dividing by time. However, limitations such as the shooting angle of the contrast image and the shape or bifurcation of the blood vessels can lead to discrepancies between the blood vessel appearance in the contrast image and the actual situation, resulting in inaccurate blood flow velocity calculations using this method. Summary of the Invention

[0003] In view of this, the purpose of this application is to provide a method and apparatus for determining blood flow velocity in blood vessels. Based on the contrast agent concentration in the contrast image, the method determines the uniformity of the contrast agent in the main vessel region and / or the contrast agent visualization of microvessels in the background region, thereby correcting the length of the flowing vessel and obtaining the corrected blood flow velocity. This reduces calculation errors caused by the imaging angle of the contrast image, the shape of the blood vessel, or vessel bifurcation, thus improving the accuracy of blood flow velocity assessment.

[0004] This application provides a method for determining blood flow velocity in a blood vessel, the method comprising:

[0005] After the contrast agent is injected, an initial contrast image and a target contrast image are acquired; wherein the initial contrast image is acquired before the contrast agent is fully saturated.

[0006] By comparing the initial contrast image and the target contrast image, the length of the blood vessel through which the contrast agent flows is determined;

[0007] Based on the contrast agent concentration in the target angiographic image, determine the uniformity of the contrast agent in the main vascular region of the target angiographic image and / or the visualization of microvessels in the background region;

[0008] Based on the uniformity of the contrast agent and / or the visualization of the microvessels, the length of the blood vessel is corrected to obtain a corrected blood vessel length.

[0009] Blood flow velocity is determined based on the corrected vessel length.

[0010] Further, determining the uniformity of contrast agent in the main vascular region of the target angiographic image includes:

[0011] The main blood vessel region is segmented from the target angiographic image;

[0012] Determine the average contrast agent concentration in the blood vessel region corresponding to the blood vessel flowing through the main blood vessel region;

[0013] The ratio of the highest contrast agent concentration in the blood vessel region to the average contrast agent concentration is defined as the contrast agent uniformity.

[0014] Furthermore, determining the uniformity of contrast agent in the main vascular region of the target angiographic image also includes:

[0015] Clustering is performed based on the contrast agent concentration in the blood vessel region to obtain multiple overlapping blood vessel sites;

[0016] For each overlapping blood vessel site, determine the ratio of the average contrast agent concentration at that overlapping blood vessel site to the average contrast agent concentration.

[0017] The uniformity of the contrast agent is obtained by weighting the ratios corresponding to each overlapping part of the blood vessels.

[0018] Further, determining the visualization of microvessels in the background region of the target contrast image includes:

[0019] Obtain the original contrast images before the injection of contrast agent;

[0020] The background region is segmented from the target imaging image;

[0021] By comparing the background region with the original contrast image, regions in the background region whose image grayscale values ​​change by more than a preset threshold are selected; wherein, the regions in the background region are used to characterize the contrast agent's imaging of microvessels in the background region.

[0022] Furthermore, based on the uniformity of the contrast agent, the length of the blood vessel is corrected to obtain a corrected blood vessel length, including:

[0023] The corrected vessel length is obtained by multiplying the uniformity of the contrast agent by the vessel length.

[0024] Furthermore, based on the visualization of the microvessels, the vessel length is corrected to obtain a corrected vessel length, including:

[0025] The volume of microvessels visualized by contrast agent in the background region is determined based on the changed region;

[0026] The equivalent vessel length is determined by dividing the volume of the microvessels by the cross-sectional area of ​​the main vessel.

[0027] The corrected blood vessel length is obtained by weighted summing of the equivalent blood vessel length and the blood vessel length.

[0028] Furthermore, based on the uniformity of the contrast agent and the visualization of the microvessels, the vessel length is corrected to obtain a corrected vessel length, including:

[0029] The first corrected vessel length is obtained by multiplying the uniformity of the contrast agent by the vessel length.

[0030] The volume of microvessels visualized by contrast agent in the background region is determined based on the changed region;

[0031] The equivalent vessel length is determined by dividing the volume of the microvessels by the cross-sectional area of ​​the main vessel.

[0032] The corrected blood vessel length is obtained by weighted summing of the first corrected blood vessel length and the equivalent blood vessel length.

[0033] This application embodiment also provides a device for determining blood flow velocity in a blood vessel, the device comprising:

[0034] An acquisition module is used to acquire an initial contrast image and a target contrast image after the contrast agent is injected; wherein the initial contrast image is acquired before the contrast agent is filled.

[0035] The comparison module is used to compare the initial contrast image and the target contrast image to determine the length of the blood vessel through which the contrast agent flows.

[0036] The first determining module is used to determine the uniformity of contrast agent in the main vascular region of the target angiography image and / or the contrast agent's imaging status in the microvessels of the background region;

[0037] The correction module is used to correct the vessel length based on the uniformity of the contrast agent and / or the visualization of the microvessels, to obtain a corrected vessel length;

[0038] The second determining module is used to determine the blood flow velocity based on the corrected blood vessel length.

[0039] 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 method for determining blood flow velocity in a blood vessel as described above are performed.

[0040] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the method for determining blood flow velocity in a blood vessel as described above.

[0041] This application provides a method and apparatus for determining blood flow velocity in a blood vessel. Based on the contrast agent concentration in angiographic images, it determines the uniformity of the contrast agent in the main vessel region and / or the contrast agent's visualization of microvessels in the background region, thereby correcting the length of the flowing vessel and obtaining a corrected blood flow velocity. This reduces calculation errors caused by the angiographic image shooting angle, vessel course, or vessel bifurcation, improving the accuracy of blood flow velocity assessment.

[0042] 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

[0043] 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.

[0044] Figure 1 A flowchart illustrating a method for determining blood flow velocity in a blood vessel, as provided in an embodiment of this application, is shown.

[0045] Figure 2 A schematic diagram of an imaging image provided in an embodiment of this application is shown;

[0046] Figure 3 A schematic diagram of the structure of a device for determining blood flow velocity in a blood vessel, provided in an embodiment of this application, is shown.

[0047] Figure 4 A schematic diagram of the structure of an electronic device provided in an embodiment of this application is shown. Detailed Implementation

[0048] 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.

[0049] Research has found that the most commonly used method for determining vascular flow velocity in contrast-enhanced functional assessment techniques is the TIMI frame-by-frame method. This method calculates blood flow velocity by observing the length of the blood vessel through which the contrast agent flows in the contrast image and dividing by the time. For example, in frame N1, the contrast agent is observed at point A in the blood vessel, and in frame N2, it is observed at point B. The distance between these two points is D. Assuming the camera's shooting speed is 15 frames per second, the blood flow velocity can be calculated using the TIMI frame-by-frame method.

[0050] However, due to limitations such as the shooting angle of the angiography image and the shape or bifurcation of blood vessels, the appearance of blood vessels in the angiography image deviates from reality. For example, in the example above, the distance between points A and B is calculated using a two-dimensional image. This calculation method ignores the fact that the actual course of the blood vessels may be curved. Since a two-dimensional angiography image is a projection of a three-dimensional blood vessel along the shooting angle, the actual length of the three-dimensional blood vessel is generally longer than the length shown on the angiography image. Furthermore, blood vessels have bifurcations. Blood flowing from upstream to downstream actually passes through many bifurcations. These bifurcations may be visible on the angiography image, or they may belong to microvessels and not be visible on the angiography image. Theoretically, each time blood passes through a bifurcation, a portion of the blood is diverted, affecting the blood flow velocity. In summary, the blood flow velocity calculated by existing methods is inaccurate.

[0051] Based on this, embodiments of this application provide a method and apparatus for determining blood flow velocity in blood vessels. According to the contrast agent concentration in the contrast image, the method determines the uniformity of the contrast agent in the main vessel region and / or the contrast agent visualization of microvessels in the background region, thereby correcting the length of the flowing vessel and obtaining the corrected blood flow velocity. This reduces calculation errors caused by the contrast image shooting angle, vessel course, or vessel bifurcation, improving the accuracy of blood flow velocity assessment.

[0052] Please see Figure 1 , Figure 1 This is a flowchart illustrating a method for determining blood flow velocity in a blood vessel, as provided in an embodiment of this application. Figure 1 As shown in the embodiments of this application, the determination method includes:

[0053] S101. After injecting the contrast agent, acquire the initial contrast image and the target contrast image.

[0054] In this step, after the contrast agent is injected, an angiography device uses a frame acquired at an initial time point as the initial angiography image, and then uses a frame acquired at a target time point as the target angiography image. The initial angiography image is acquired before the contrast agent fills the coronary arteries, and there is a certain interval between the acquisition times of the initial and target angiography images. Taking coronary angiography as an example, by injecting contrast agent into the coronary arteries and then contrasting the contrast agent with X-rays, the flow of the contrast agent can be observed, and the blood flow can be roughly estimated.

[0055] S102. Compare the initial contrast image and the target contrast image to determine the length of the blood vessel through which the contrast agent flows.

[0056] Please see Figure 2 , Figure 2 This is a schematic diagram of an imaging image provided in an embodiment of this application. Figure 2 As shown, due to the different degrees of light transmittance of contrast agents and different human tissues, their appearance in contrast images also differs. In this step, the location to which the contrast agent flows can be determined by observing the contrast images, and then the length through which the contrast agent flows in the contrast images can be determined by comparing two frames of contrast images. Furthermore, because there is a mapping relationship between contrast images and physiological vascular structures, the length of the blood vessels through which the contrast agent flows can be determined.

[0057] S103. Based on the contrast agent concentration in the target angiographic image, determine the uniformity of the contrast agent in the main vascular region of the target angiographic image and / or the visualization of microvessels in the background region.

[0058] It should be noted that the contrast agent concentration in this embodiment refers to the contrast agent concentration displayed in the contrast image, not the concentration in the medical sense at the time of contrast agent injection. Here, the contrast agent concentration displayed in the contrast image is determined based on the grayscale value of the pixels in the image. The grayscale value of the pixel can be directly determined as the contrast agent concentration at the corresponding location, or a certain mapping relationship can be set to convert the grayscale value into the contrast agent concentration at the corresponding location.

[0059] In this step, the main vascular region and background region in the angiographic image can be distinguished using methods in the prior art, such as vascular segmentation models. The embodiments of this application have found that angiographic images often suffer from two problems: overlapping vascular visualization and the inability to observe microvessels.

[0060] Regarding the issue of overlapping vascular imaging, in the main vessel area, where the contrast agent concentration is higher ( Figure 2The darker areas (in the center) are often due to the tortuous shape of the blood vessel along the projection direction, causing local overlap of the contrast agent projection and uneven contrast agent concentration. Contrast agent concentration can reflect the actual distance of blood flow, so by combining contrast agent concentration information with the morphology of the blood vessel, the true length of the blood vessel can be calculated, thereby correcting the blood flow velocity.

[0061] For problems that cannot be observed in microvessels, such as Figure 2 As shown, besides the main blood vessel region, the background area reveals some microvessels that are difficult to distinguish using the vascular segmentation model. Many microvessels are also invisible in the contrast image due to limited contrast resolution, failing to show a clear vascular outline. However, because microvessels are extremely densely distributed in actual physiological anatomy, their visualization after contrast agent injection results in the background area appearing gray. Therefore, contrast agent concentration can reflect the actual flow area of ​​blood. For microvessels whose specific diameter cannot be observed, changes in contrast agent concentration in the background area can reveal their visualization, allowing for estimation of the branches of the main blood vessel and thus a more accurate estimation of flow changes in the main blood vessel, ultimately correcting for blood flow velocity.

[0062] In one possible implementation, determining the contrast agent uniformity in the main vessel region of the target angiographic image in step S103 includes:

[0063] The main blood vessel region is segmented from the target contrast image; the average contrast agent concentration of the flowing blood vessel region corresponding to the flowing blood vessel in the main blood vessel region is determined; the ratio of the highest contrast agent concentration in the flowing blood vessel region to the average contrast agent concentration is determined as the contrast agent uniformity.

[0064] In practice, a pre-trained vessel segmentation model can be used to segment the main vessel region from the target angiographic image. The contrast agent concentration corresponding to each pixel in the main vessel region is determined based on its grayscale value. Then, the flow vessel region corresponding to the contrast agent flowing through the vessel from the initial angiographic image to the target angiographic image is determined, thereby determining the average contrast agent concentration in the flow vessel region. Finally, the pixel with the highest contrast agent concentration is selected from the flow vessel region, and the contrast agent concentration of this pixel and the average contrast agent concentration are used to determine the contrast agent uniformity k. Therefore, the contrast agent uniformity is positively correlated with the value of k; if the contrast agent concentration is completely uniform, then k = 1; if the contrast agent concentration is not completely uniform, then k > 1.

[0065] Furthermore, step S103, determining the uniformity of contrast agent in the main vascular region of the target angiographic image, further includes:

[0066] Clustering is performed based on the contrast agent concentration in the blood vessel region to obtain multiple overlapping blood vessel sites; for each overlapping blood vessel site, the ratio of the average contrast agent concentration of the overlapping blood vessel site to the average contrast agent concentration is determined; the weighted average of the ratios corresponding to each overlapping blood vessel site is then performed to obtain the contrast agent uniformity.

[0067] In practical implementation, considering that there may be multiple overlaps along the main blood vessels, a clustering algorithm can be used to cluster the contrast agent concentration in the flowing vessel region to obtain multiple overlapping vessel sites and determine the average contrast agent concentration of each overlapping vessel site. Then, the ratio of the average contrast agent concentration of each overlapping vessel site to the overall average contrast agent concentration of the flowing vessel region is determined. Finally, the ratios corresponding to each overlapping vessel site are weighted and averaged to obtain the contrast agent uniformity. The weight of the ratio corresponding to each overlapping vessel site can be determined by considering the size of the overlapping vessel site, the number of vessels involved, etc., and can be expressed by the following formula:

[0068]

[0069] In the formula, k represents the homogeneity of the contrast agent; w i k represents the weight of the overlapping region of the i-th blood vessel; i This represents the weight of the i-th overlapping blood vessel region, corresponding to the ratio of the i-th overlapping blood vessel region.

[0070] In another possible implementation, step S103, determining the visualization of microvessels in the background region of the target angiographic image, includes:

[0071] Obtain the original contrast image before contrast agent injection; segment the background region from the target contrast image; compare the background region with the original contrast image, and select the change region from the background region whose image grayscale value changes exceed a preset threshold; wherein, the change region is used to characterize the contrast agent's imaging of microvessels in the background region.

[0072] In practice, a pre-trained vascular segmentation model can be used to segment the background region from the target angiographic image. By comparing the background region with the original angiographic image before the injection of contrast agent, regions with changes in image grayscale values ​​exceeding a preset threshold can be selected from the background region. These regions represent the imaging of microvessels in the background region by the contrast agent.

[0073] S104. Based on the uniformity of the contrast agent and / or the imaging of the microvessels, the length of the blood vessel is corrected to obtain a corrected blood vessel length.

[0074] S105. Determine the blood flow velocity based on the corrected blood vessel length.

[0075] In one possible implementation, when correcting the vessel length based solely on the contrast agent uniformity, step S104, which corrects the vessel length based on the contrast agent uniformity to obtain the corrected vessel length, includes multiplying the contrast agent uniformity by the vessel length to obtain the corrected vessel length.

[0076] Subsequently, the blood flow velocity can be determined based on the corrected vessel length and the time interval between the initial and target angiographic images. The formula for calculating the blood flow velocity can then be expressed as:

[0077]

[0078] In the formula, k represents the uniformity of the contrast agent; D represents the length of the blood vessel; N2 represents the number of frames corresponding to the target contrast image; N1 represents the number of frames corresponding to the initial contrast image; and N represents the number of frames captured by the imaging device per unit time.

[0079] In a second possible implementation, when correcting the vessel length based solely on the visualization of microvessels, step S104 involves correcting the vessel length based on the visualization of the microvessels to obtain the corrected vessel length, including:

[0080] The volume of microvessels visualized by contrast agent in the background region is determined based on the changed region; the equivalent vessel length is determined by dividing the microvessel volume by the cross-sectional area of ​​the main vessel; the corrected vessel length is obtained by weighted summing of the equivalent vessel length and the vessel length.

[0081] In practical implementation, taking coronary arteries as an example, since blood vessels are generated within the myocardium and the thickness of the human myocardium is basically uniform, the product of the area of ​​variation and the myocardial thickness is determined as the microvessel volume visualized by contrast agent in the background area; the microvessel volume is divided by the cross-sectional area of ​​the main blood vessel to determine the equivalent blood vessel length; the equivalent blood vessel length is weighted and summed with the blood vessel length to obtain the corrected blood vessel length.

[0082] Subsequently, the blood flow velocity can be determined based on the corrected vessel length and the time interval between the initial and target angiographic images. The formula for calculating the blood flow velocity can then be expressed as:

[0083]

[0084] In the formula, α represents the weight corresponding to the vessel length; β represents the weight corresponding to the equivalent vessel length; V represents the volume of microvessels visualized by contrast agent in the background region; and A represents the cross-sectional area of ​​the main vessel.

[0085] In a third possible implementation, when correcting the vessel length based on both the uniformity of the contrast agent and the visualization of microvessels, step S104 involves correcting the vessel length based on both the uniformity of the contrast agent and the visualization of microvessels to obtain the corrected vessel length, including:

[0086] The first corrected vessel length is obtained by multiplying the uniformity of the contrast agent by the vessel length; the volume of microvessels visualized by the contrast agent in the background region is determined based on the region of change; the equivalent vessel length is determined by dividing the microvessel volume by the cross-sectional area of ​​the main vessel; and the corrected vessel length is obtained by weighted summing of the first corrected vessel length and the equivalent vessel length.

[0087] At this point, the formula for calculating blood flow velocity can be expressed as:

[0088]

[0089] Furthermore, after calculating the blood flow velocity, the vascular flow rate Q can be calculated by combining it with the cross-sectional area of ​​the main blood vessel. The formula can be expressed as:

[0090] Q = uA

[0091] Q can be the inflow rate of the entire coronary tree or the local flow rate of a portion of the blood vessels.

[0092] Furthermore, after obtaining the flow rate information, FFR, IMR, or other functional parameters can be calculated further. Therefore, the blood flow velocity determined in this embodiment can provide more reliable hemodynamic information for subsequent correlation analysis based on contrast images, indirectly improving the accuracy of other functional parameters.

[0093] This application provides a method for determining blood flow velocity in a blood vessel, comprising: acquiring an initial contrast image and a target contrast image after injecting a contrast agent; wherein the initial contrast image is acquired before the contrast agent fills the vessel; comparing the initial contrast image and the target contrast image to determine the vessel length through which the contrast agent flows; determining the contrast agent uniformity in the main vessel region and / or the visualization of microvessels in the background region of the target contrast image based on the contrast agent concentration in the target contrast image; correcting the vessel length based on the contrast agent uniformity and / or the visualization of microvessels to obtain a corrected vessel length; and determining the blood flow velocity based on the corrected vessel length.

[0094] In this way, based on the contrast agent concentration in the angiographic image, the uniformity of the contrast agent in the main vessel region and / or the visualization of microvessels in the background region are determined, thereby correcting the length of the flowing vessel and obtaining the corrected blood flow velocity. This reduces calculation errors caused by factors such as the angiographic image shooting angle, vessel course, or vessel bifurcation, improving the accuracy and precision of blood flow velocity assessment.

[0095] Please see Figure 3 , Figure 3 This is a schematic diagram of a device for determining blood flow velocity in a blood vessel, provided in an embodiment of this application. Figure 3 As shown, the determining device 300 includes:

[0096] The acquisition module 310 is used to acquire an initial contrast image and a target contrast image after the contrast agent is injected; wherein the initial contrast image is acquired before the contrast agent is filled.

[0097] Comparison module 320 is used to compare the initial contrast image and the target contrast image to determine the length of the blood vessel through which the contrast agent flows.

[0098] The first determining module 330 is used to determine the uniformity of contrast agent in the main vascular region of the target angiography image and / or the imaging of microvessels of contrast agent in the background region.

[0099] The correction module 340 is used to correct the vessel length based on the uniformity of the contrast agent and / or the imaging of the microvessels to obtain a corrected vessel length.

[0100] The second determining module 350 is used to determine the blood flow velocity based on the corrected blood vessel length.

[0101] Furthermore, the first determining module 330 determines the uniformity of contrast agent in the main vascular region of the target angiographic image, including:

[0102] The main blood vessel region is segmented from the target angiographic image;

[0103] Determine the average contrast agent concentration in the blood vessel region corresponding to the blood vessel flowing through the main blood vessel region;

[0104] The ratio of the highest contrast agent concentration in the blood vessel region to the average contrast agent concentration is defined as the contrast agent uniformity.

[0105] Furthermore, the first determining module 330, in determining the uniformity of contrast agent in the main vascular region of the target angiographic image, further includes:

[0106] Clustering is performed based on the contrast agent concentration in the blood vessel region to obtain multiple overlapping blood vessel sites;

[0107] For each overlapping blood vessel site, determine the ratio of the average contrast agent concentration at that overlapping blood vessel site to the average contrast agent concentration.

[0108] The uniformity of the contrast agent is obtained by weighting the ratios corresponding to each overlapping part of the blood vessels.

[0109] Furthermore, the first determining module 330 determines the visualization of microvessels in the background region of the target contrast image, including:

[0110] Obtain the original contrast images before the injection of contrast agent;

[0111] The background region is segmented from the target imaging image;

[0112] By comparing the background region with the original contrast image, regions in the background region whose image grayscale values ​​change by more than a preset threshold are selected; wherein, the regions in the background region are used to characterize the contrast agent's imaging of microvessels in the background region.

[0113] Furthermore, the correction module 340 corrects the vessel length based on the contrast agent uniformity to obtain a corrected vessel length, including:

[0114] The corrected vessel length is obtained by multiplying the uniformity of the contrast agent by the vessel length.

[0115] Furthermore, the correction module 340 corrects the vessel length based on the visualization of the microvessels to obtain a corrected vessel length, including:

[0116] The volume of microvessels visualized by contrast agent in the background region is determined based on the changed region;

[0117] The equivalent vessel length is determined by dividing the volume of the microvessels by the cross-sectional area of ​​the main vessel.

[0118] The corrected blood vessel length is obtained by weighted summing of the equivalent blood vessel length and the blood vessel length.

[0119] Furthermore, the correction module 340 corrects the vessel length based on the uniformity of the contrast agent and the visualization of the microvessels, obtaining a corrected vessel length, including:

[0120] The first corrected vessel length is obtained by multiplying the uniformity of the contrast agent by the vessel length.

[0121] The volume of microvessels visualized by contrast agent in the background region is determined based on the changed region;

[0122] The equivalent vessel length is determined by dividing the volume of the microvessels by the cross-sectional area of ​​the main vessel.

[0123] The corrected blood vessel length is obtained by weighted summing of the first corrected blood vessel length and the equivalent blood vessel length.

[0124] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 400 includes a processor 410, a memory 420, and a bus 430.

[0125] The memory 420 stores machine-readable instructions executable by the processor 410. When the electronic device 400 is running, the processor 410 communicates with the memory 420 via the bus 430. When the machine-readable instructions are executed by the processor 410, they can perform the operations described above. Figure 1 The steps of a method for determining blood flow velocity in a blood vessel in the illustrated embodiment can be found in the method embodiment for specific implementation, and will not be repeated here.

[0126] 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 The steps of a method for determining blood flow velocity in a blood vessel in the illustrated embodiment can be found in the method embodiment for specific implementation, and will not be repeated here.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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 of determining blood flow velocity in a blood vessel, characterized by, The determination method includes: After the contrast agent is injected, an initial contrast image and a target contrast image are acquired; wherein the initial contrast image is acquired before the contrast agent is fully saturated. By comparing the initial contrast image and the target contrast image, the length of the blood vessel through which the contrast agent flows is determined; Based on the contrast agent concentration in the target angiographic image, determine the uniformity of the contrast agent in the main vascular region of the target angiographic image and / or the visualization of microvessels in the background region; Based on the uniformity of the contrast agent and / or the visualization of the microvessels, the length of the blood vessel is corrected to obtain a corrected blood vessel length. Blood flow velocity is determined based on the corrected vessel length; Determining the visualization of microvessels in the background region of the target angiographic image includes: Obtain the original contrast images before the injection of contrast agent; The background region is segmented from the target imaging image; By comparing the background region with the original contrast image, regions in the background region whose image grayscale values ​​change by more than a preset threshold are selected; wherein, the regions in the background region are used to characterize the contrast agent's imaging of microvessels in the background region.

2. The method according to claim 1, characterized in that, Determining the contrast agent uniformity in the main vessel region of the target angiographic image includes: The main blood vessel region is segmented from the target angiographic image; Determine the average contrast agent concentration in the blood vessel region corresponding to the blood vessel flowing through the main blood vessel region; The ratio of the highest contrast agent concentration in the blood vessel region to the average contrast agent concentration is defined as the contrast agent uniformity.

3. The determination method according to claim 2, characterized in that, Determining the uniformity of contrast agent in the main vessel region of the target angiographic image further includes: Clustering is performed based on the contrast agent concentration in the blood vessel region to obtain multiple overlapping blood vessel sites; For each overlapping blood vessel site, determine the ratio of the average contrast agent concentration at that overlapping blood vessel site to the average contrast agent concentration. The uniformity of the contrast agent is obtained by weighting the ratios corresponding to each overlapping part of the blood vessels.

4. The determination method according to claim 2 or 3, characterized in that, Based on the uniformity of the contrast agent, the length of the blood vessel is corrected to obtain a corrected blood vessel length, including: The corrected vessel length is obtained by multiplying the uniformity of the contrast agent by the vessel length.

5. The determination method according to claim 1, characterized in that, Based on the visualization of the microvessels, the vessel length is corrected to obtain a corrected vessel length, including: The volume of microvessels visualized by contrast agent in the background region is determined based on the changed region; The equivalent vessel length is determined by dividing the volume of the microvessels by the cross-sectional area of ​​the main vessel. The corrected blood vessel length is obtained by weighted summing of the equivalent blood vessel length and the blood vessel length.

6. The determination method of claim 1, wherein, Based on the uniformity of the contrast agent and the visualization of the microvessels, the length of the blood vessel is corrected to obtain a corrected blood vessel length, including: The first corrected vessel length is obtained by multiplying the uniformity of the contrast agent by the vessel length. The volume of microvessels visualized by contrast agent in the background region is determined based on the changed region; The equivalent vessel length is determined by dividing the volume of the microvessels by the cross-sectional area of ​​the main vessel. The corrected blood vessel length is obtained by weighted summing of the first corrected blood vessel length and the equivalent blood vessel length.

7. An apparatus for determining a blood flow velocity in a blood vessel, characterized by The determining device includes: An acquisition module is used to acquire an initial contrast image and a target contrast image after the contrast agent is injected; wherein the initial contrast image is acquired before the contrast agent is filled. The comparison module is used to compare the initial contrast image and the target contrast image to determine the length of the blood vessel through which the contrast agent flows. The first determining module is used to determine the uniformity of contrast agent in the main vascular region of the target angiography image and / or the contrast agent's imaging status in the microvessels of the background region; The correction module is used to correct the vessel length based on the uniformity of the contrast agent and / or the visualization of the microvessels, to obtain a corrected vessel length; The second determining module is used to determine the blood flow velocity based on the corrected blood vessel length; The first determining module determines the visualization of microvessels in the background region of the target angiographic image, including: Obtain the original contrast images before the injection of contrast agent; The background region is segmented from the target imaging image; By comparing the background region with the original contrast image, regions in the background region whose image grayscale values ​​change by more than a preset threshold are selected; wherein, the regions in the background region are used to characterize the contrast agent's imaging of microvessels in the background region.

8. An electronic device, comprising: include: The device includes 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. The machine-readable instructions are executed by the processor to perform the steps of a method for determining blood flow velocity in a blood vessel as described in any one of claims 1 to 6.

9. 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 a method for determining blood flow velocity in a blood vessel as described in any one of claims 1 to 6.

Images