A blood flow velocity determination method and apparatus, electronic device, and storage medium

Abstract

The application provides a blood flow velocity determination method and device, electronic equipment and storage medium. The determination method comprises the following steps: determining a first blood vessel center line in a first contrast image and a second blood vessel center line in a second contrast image, and mapping the first blood vessel center line to the second contrast image to obtain a center line mapping image; when there is no new blood vessel branch in the second blood vessel center line, determining the blood flow velocity corresponding to a new blood vessel segment based on the coordinates of each center point in the first blood vessel center line and each center point in the second blood vessel center line in the center line mapping image; when there is a new blood vessel branch in the second blood vessel center line, determining the blood flow velocity corresponding to each new blood vessel segment based on the coordinates of each center point in the first blood vessel center line and each center point in the second blood vessel center line in the center line mapping image. According to the determination method and the determination device, the accuracy and efficiency of blood flow velocity calculation are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of medical image processing, in particular to a blood flow velocity determination method and device, electronic equipment and storage medium. BACKGROUND

[0002] In an angiography image, blood flow velocity is an important functional factor for evaluating the health of blood vessels. For example, when a doctor issues a coronary angiography diagnosis report, the doctor will give a flow velocity rating. In the calculation of FFR based on angiography, blood flow velocity is an important mechanical parameter, and accurate flow velocity is the key to accurate calculation results. By fully utilizing the characteristics of the dynamic sequence of angiography and the structure of the continuously filling coronary tree, the global flow velocity can be calculated to adapt to complex actual situations of the coronary tree.

[0003] Currently, in the existing blood flow velocity calculation method, only the average flow velocity of a single blood vessel is calculated. However, the actual situation of the blood vessel is complex, and due to the existence of multiple branches, the blood flow velocity changes at different positions in the blood vessel tree. Therefore, it is difficult to meet some complex actual situations by using the average flow velocity of a single blood vessel. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a blood flow velocity determination method and device, electronic equipment and storage medium. In the dynamic angiography image, by performing global dynamic analysis on the image, fully utilizing the characteristics of the dynamic sequence of angiography and the structure of the continuously filling blood vessel tree, obtaining the dynamic centerline length change, and performing local flow velocity calculation according to the two strategies of no branch blood vessel and branch blood vessel, the complex blood vessel structure can be adapted, and the accuracy and efficiency of blood flow velocity calculation are improved.

[0005] In a first aspect, the embodiments of the present application provide a blood flow velocity determination method, which comprises:

[0006] An angiography video is obtained, and a first frame angiography image with a blood vessel image in the angiography video is taken as a first angiography image, and a next frame angiography image adjacent to the first angiography image in the angiography video is taken as a second angiography image;

[0007] A first blood vessel centerline in the first angiography image and a second blood vessel centerline in the second angiography image are determined, and the first blood vessel centerline in the first angiography image is mapped to the second angiography image to obtain a centerline mapping image;

[0008] when the second vessel centerline has no new vessel branch compared with the first vessel centerline, then determining the blood flow velocity corresponding to each new vessel segment in the second vessel centerline based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image;

[0009] when the second vessel centerline has no new vessel branch compared with the first vessel centerline, then determining the blood flow velocity corresponding to each new vessel segment in the second vessel centerline based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image;

[0010] Further, after obtaining the centerline mapping image, the determination method further comprises:

[0011] mapping the first catheter region in the first contrast image and the second catheter region in the second contrast image to the centerline mapping image;

[0012] skeletonizing the first catheter region in the centerline mapping image to obtain a first catheter centerline, and skeletonizing the second catheter region to obtain a second catheter centerline;

[0013] calculating a translation vector between the first catheter centerline and the second catheter centerline, and translating the first catheter centerline based on the translation vector in the centerline mapping image, and taking the centerline mapping image after centerline translation as the centerline mapping image.

[0014] Further, whether the second vessel centerline has a new vessel branch is determined by the following steps:

[0015] determining the number of first end points corresponding to the first vessel centerline, and the number of second end points corresponding to the second vessel centerline;

[0016] when the number of second end points is greater than the number of first end points, it is determined that the second vessel centerline has the new vessel branch.

[0017] Further, the determination of the blood flow velocity corresponding to each new vessel segment in the second vessel centerline based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image comprises:

[0018] determining a distance between each center point in the second vessel centerline and a vessel endpoint of the first vessel centerline, determining a first center point in the second vessel centerline closest to the vessel endpoint of the first vessel centerline, and taking a vessel centerline between the first center point and a vessel endpoint of the second vessel centerline as the new vessel segment;

[0019] determining a vessel starting point of the second vessel centerline from each center point in the second vessel centerline, and calculating a first length from the vessel starting point to the first center point using coordinates of other center points in the second vessel centerline between the vessel starting point and the first center point in the centerline mapping image, and taking the first length as a previous frame vessel length;

[0020] calculating a second length of the second vessel centerline based on coordinates of each center point in the second vessel centerline in the centerline mapping image, and taking the second length as a current frame vessel length;

[0021] determining a length change value as a difference between the current frame vessel length and the previous frame vessel length, and taking a quotient of the length change value and a contrast image frame rate as a blood flow velocity corresponding to the new vessel segment.

[0022] Further, the determining of the blood flow velocity corresponding to each new vessel segment in the second vessel centerline based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image comprises:

[0023] determining a distance between each center point in the second vessel centerline and a vessel endpoint of the first vessel centerline, determining a second center point in the second vessel centerline closest to the vessel endpoint of the first vessel centerline, and taking a vessel centerline between the second center point and multiple vessel endpoints of the second vessel centerline as new vessel branch segments;

[0024] dividing the new vessel branch segments into multiple new vessel segments, and determining a vessel length corresponding to each new vessel segment;

[0025] for each new vessel segment, determining a blood flow velocity equation expression corresponding to the new vessel segment based on a vessel length corresponding to the new vessel segment and a blood flow time corresponding to the new vessel segment;

[0026] According to the relationship between the total flow before the blood vessel bifurcation and the total flow after the blood vessel bifurcation, the blood flow velocity solving formula corresponding to each new blood vessel segment is obtained by combining the plurality of blood flow velocity equation expressions, and the blood flow velocity corresponding to each new blood vessel segment is solved based on the blood flow velocity solving formula corresponding to each new blood vessel segment.

[0027] Further, the dividing the new blood vessel branch segment into a plurality of new blood vessel segments comprises:

[0028] For each center point in the new blood vessel branch segment, the number of center points of other center points adjacent to the center point in the new blood vessel branch segment is determined;

[0029] When the number of center points is greater than or equal to 3, the center point is determined as a branch node;

[0030] Based on the branch node, the blood vessel starting point in the new blood vessel branch segment, and the plurality of blood vessel ending points in the new blood vessel branch segment, a plurality of new blood vessel segments are determined.

[0031] Further, after the blood flow velocity corresponding to the new blood vessel segment in the second blood vessel center line is determined, or after the blood flow velocity corresponding to each new blood vessel segment in the second blood vessel center line is determined, the determination method further comprises:

[0032] The second contrast image is taken as the first contrast image, and the step of taking the next frame contrast image adjacent to the first contrast image in the angiography video as the second contrast image is returned to be executed until there is no next frame contrast image adjacent to the first contrast image in the angiography video.

[0033] In a second aspect, the embodiments of the present application also provide a blood flow velocity determination device, the determination device comprising:

[0034] A contrast image acquisition module is configured to acquire an angiography video, take a first frame contrast image with a blood vessel image in the angiography video as a first contrast image, and take a next frame contrast image adjacent to the first contrast image in the angiography video as a second contrast image;

[0035] A center line mapping image determination module is configured to determine a first blood vessel center line in the first contrast image and a second blood vessel center line in the second contrast image, and map the first blood vessel center line in the first contrast image to the second contrast image to obtain a center line mapping image;

[0036] a first blood flow velocity determination module configured to determine blood flow velocities corresponding to new vessel segments in the second vessel centerline based on coordinates of each center point in the first vessel centerline in the centerline mapping image and coordinates of each center point in the second vessel centerline in the centerline mapping image when the second vessel centerline has no new vessel branch compared with the first vessel centerline;

[0037] a second blood flow velocity determination module configured to determine blood flow velocities corresponding to each new vessel segment in the second vessel centerline based on coordinates of each center point in the first vessel centerline in the centerline mapping image and coordinates of each center point in the second vessel centerline in the centerline mapping image when the second vessel centerline has new vessel branch compared with the first vessel centerline.

[0038] In a third aspect, an electronic device is provided, which 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 through the bus. The machine readable instructions are executed by the processor to perform the steps of the blood flow velocity determination method as described above.

[0039] In a fourth aspect, a computer readable storage medium is provided, which stores a computer program. When the computer program is run by a processor, the steps of the blood flow velocity determination method as described above are performed.

[0040] The method and device for determining blood flow velocity provided by the embodiments of the present application first acquire an angiography video, take a first frame of angiography image with a blood vessel image in the angiography video as a first angiography image, and take a next frame of angiography image adjacent to the first angiography image in the angiography video as a second angiography image. Then, a first blood vessel center line in the first angiography image and a second blood vessel center line in the second angiography image are determined, and the first blood vessel center line in the first angiography image is mapped to the second angiography image to obtain a center line mapping image. When the second blood vessel center line has no new blood vessel branch compared with the first blood vessel center line, the blood flow velocity corresponding to a new blood vessel segment in the second blood vessel center line is determined based on the coordinates of each center point in the first blood vessel center line in the center line mapping image and the coordinates of each center point in the second blood vessel center line in the center line mapping image. When the second blood vessel center line has a new blood vessel branch compared with the first blood vessel center line, the blood flow velocity corresponding to each new blood vessel segment in the second blood vessel center line is determined based on the coordinates of each center point in the first blood vessel center line in the center line mapping image and the coordinates of each center point in the second blood vessel center line in the center line mapping image.

[0041] Compared with the blood flow velocity determination method in the prior art, the present application fully utilizes the features of the angiography dynamic sequence and the constantly filling blood vessel tree structure in the dynamic angiography image, obtains the dynamic center line length change through the global dynamic analysis of the image, and performs local flow velocity calculation according to the two strategies of no blood vessel branch and blood vessel branch, which can adapt to complex blood vessel structures and improve the accuracy and efficiency of blood flow velocity calculation.

[0042] In order to make the above objectives, characteristics and advantages of the present application more apparent and understandable, the following preferred embodiments are specifically described below, and the accompanying drawings are referred to, and the detailed description is as follows. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0044] Figure 1 The flow chart of the method for determining blood flow velocity provided by the embodiments of the present application;

[0045] Figure 2Structure schematic view of a blood flow velocity determination device provided in an embodiment of the present application;

[0046] Figure 3 Structure schematic view of a blood flow velocity determination device provided in an embodiment of the present application;

[0047] Figure 4 Structure schematic view of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0048] In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings for the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, every other embodiment obtained by a person skilled in the art without creative work falls within the scope of protection of the present application.

[0049] First, the application scenarios applicable to the present application are introduced. The present application can be applied to the technical field of medical image processing.

[0050] In an angiographic image, blood flow velocity is an important functional factor for evaluating the health degree of a blood vessel. For example, when a doctor issues a coronary angiography diagnosis report, a flow velocity rating is given. When performing a contrast-based FFR calculation, blood flow velocity is an important mechanical parameter, and accurate flow velocity is a key to precise calculation results. Fully utilizing the features of a contrast dynamic sequence and a continuously filling coronary tree structure, a global flow velocity is calculated, which can adapt to complex actual situations of a blood vessel coronary tree.

[0051] It is found through research that, at present, in the existing blood flow velocity calculation methods, only the average flow velocity of a single blood vessel is often calculated. However, the actual situation of a blood vessel is complex, and due to the existence of multiple branches, the blood flow velocity changes differently at different positions in a blood vessel tree, so it is difficult to meet some complex actual situations by using the average flow velocity of a single blood vessel.

[0052] Based on this, the embodiments of the present application provide a blood flow velocity determination method to improve the accuracy and efficiency of blood flow velocity calculation.

[0053] Please refer to Figure 1 , Figure 1 Flowchart of a blood flow velocity determination method provided in an embodiment of the present application. As shown in FIG. 1, the method comprises the following steps.Figure 1 As shown in the method for determining blood flow velocity provided by the embodiments of the present application, the method comprises the following steps:

[0054] In step S101, an angiography video is acquired, a first frame angiography image with a blood vessel image in the angiography video is taken as a first angiography image, and a next frame angiography image adjacent to the first angiography image in the angiography video is taken as a second angiography image.

[0055] It should be noted that the first angiography image refers to the first frame angiography image when the blood vessel image appears in the angiography video after the injection of the angiography agent into the vein. The second angiography image refers to the next frame angiography image adjacent to the first angiography image in the angiography video.

[0056] In the implementation of step S101, the angiography video is acquired, the first frame angiography image with the blood vessel image in the angiography video is taken as the first angiography image, and the next frame angiography image adjacent to the first angiography image in the angiography video is taken as the second angiography image.

[0057] In step S102, a first blood vessel center line in the first angiography image and a second blood vessel center line in the second angiography image are determined, and the first blood vessel center line in the first angiography image is mapped to the second angiography image to obtain a center line mapping image.

[0058] It should be noted that the blood vessel center line refers to a connecting line along the center of the blood vessel in the blood vessel angiography image in the blood vessel region, which can be represented as a series of center point pixels.

[0059] In the implementation of step S102, after the first angiography image and the second angiography image are determined, the first blood vessel center line in the first angiography image is determined, the second blood vessel center point in the second angiography image is determined, and then the first blood vessel center line in the first angiography image is mapped to the second angiography image. At this time, the first blood vessel center line and the second blood vessel center line exist in the mapped second angiography image, and the mapped second angiography image is determined as the center line mapping image.

[0060] In the step S102, the blood vessel starting point in the angiography image is needed to be obtained before determining the blood vessel centerline. Alternatively, the blood vessel starting point can be obtained in the following ways: (1) manually selecting the blood vessel starting point; (2) learning a large number of labeled blood vessel starting points by supervised learning, and then using a neural network model to predict the position of the starting point; (3) positioning the catheter, and taking the tail end of the catheter as the blood vessel starting point. After obtaining the blood vessel starting point in the angiography image, the region growing is performed along the "feature map" of the blood vessel starting point to obtain the blood vessel centerline in the angiography image. The "feature map" can be obtained in the following ways: (1) directly using the original angiography image as the "feature map"; (2) performing frangi filtering enhancement on the original angiography image, and then performing threshold segmentation on the enhanced result to obtain a binary result as the "feature map"; (3) learning a large number of binary segmented blood vessel trees by supervised learning, and then using a neural network model to predict the binary segmented region of the blood vessel as the "feature map". If a non-binary map is used as the "feature map", the growing boundary condition needs to be set, such as setting a map range [gmin, gmax], wherein gmin represents the lowest map gray value meeting the growing condition, and gmax represents the highest map gray value meeting the growing condition, and the growing is stopped if the threshold range is exceeded. If a binary map is used as the "feature map", the growing boundary condition is relatively simple, that is, the map foreground (gray value = 1) is the growing region, and the background region (gray value = 0) does not meet the growing condition and does not grow in the region. The method for obtaining the blood vessel centerline in the angiography image is described in detail in the prior art, and will not be described here.

[0061] Specifically, for the step S102, after obtaining the centerline mapping image, the determination method further comprises:

[0062] Step 1021, mapping the first catheter region in the first angiography image and the second catheter region in the second angiography image to the centerline mapping image.

[0063] Step 1022, skeletonizing the first catheter region in the centerline mapping image to obtain a first catheter centerline, and skeletonizing the second catheter region to obtain a second catheter centerline.

[0064] Step 1023, calculating a translation vector between the first catheter centerline and the second catheter centerline, and translating the first catheter centerline based on the translation vector in the centerline mapping image, and taking the centerline mapping image after the centerline translation as the centerline mapping image.

[0065] When the cardiac coronary angiography is performed, due to the movement of the heart, the position of the coronary tree region on the angiography image changes regularly over time, thus causing a certain offset and deformation between the coronary tree vessel centerline structure in the previous frame image and the coronary tree vessel centerline structure in the current frame image. Therefore, the matching of the previous frame vessel centerline and the current frame vessel centerline needs to be performed. For the above steps 1021-1023, in the specific implementation, first, the first catheter region corresponding to the catheter in the first angiography image is determined, and the second catheter region corresponding to the catheter in the second angiography image is determined, then the first catheter region in the first angiography image and the second catheter region in the second angiography image are mapped to the centerline mapping image, and the first catheter region is skeletonized in the centerline mapping image to obtain the first catheter centerline, and the second catheter region is skeletonized to obtain the second catheter centerline. Here, the method of skeletonization is described in detail in the prior art, which will not be repeated here. After obtaining the first catheter centerline and the second catheter centerline, the translation vector between the first catheter centerline and the second catheter centerline is calculated. Specifically, the distance between the catheter center point in the second catheter centerline closest to the catheter end point of the first catheter centerline and the catheter end point of the first catheter centerline is taken as the translation vector. Then the first catheter centerline is translated in the centerline mapping image based on the translation vector, and the centerline after translation is taken as the centerline mapping image. In this way, when the vessel centerline is offset, the vessel centerlines of the previous and subsequent two frames can be matched, and the accuracy of the subsequent blood flow velocity calculation is improved.

[0066] As an optional implementation, the matching of the previous frame vessel centerline and the current frame vessel centerline can also have the following two ways: (1) rigid registration based on the vessel, since the deformation of the adjacent two frames of the vessel is relatively small, it can be assumed to be rigid transformation, only rotation translation and scaling transformation exist, which will bring a small amount of error, but the calculation speed is fast; (2) non-rigid registration based on the vessel, the vessel is a soft tissue structure, this way is more in line with the actual situation, but the calculation amount is large, and the calculation time is long. The technologies of rigid registration and non-rigid registration are described in detail in the prior art, which will not be repeated here.

[0067] In a complex blood vessel structure tree, there may be blood vessel branches. In order to ensure the accuracy of the blood flow velocity calculation, the application performs local flow velocity calculation according to two strategies of no branch and branch. Therefore, according to the blood flow velocity determination method provided by the application, before the blood flow velocity is calculated, it is also necessary to judge whether there is a new blood vessel branch in the second frame angiography image, that is, whether there is a new blood vessel branch in the second vessel centerline.

[0068] Specifically, whether there is a new blood vessel branch in the second vessel centerline is judged by the following steps:

[0069] determining a first number of end points corresponding to the first vessel centerline and a second number of end points corresponding to the second vessel centerline; and determining that the second vessel centerline includes the new vessel branch when the second number of end points is greater than the first number of end points.

[0070] If the second vessel centerline includes a new vessel branch compared to the first vessel centerline, the second vessel centerline includes at least one more end point than the first vessel centerline. For the above two steps, in a specific implementation, first, a first number of end points corresponding to the first vessel centerline and a second number of end points corresponding to the second vessel centerline are determined. Then, the first number of end points is compared with the second number of end points. When the second number of end points is greater than the first number of end points, it is determined that the second vessel centerline includes a new vessel branch. Then, the blood flow velocity corresponding to the newly added vessel branch segment is calculated through step S104. When the first number of end points is equal to the second number of end points, it is determined that the second vessel centerline does not include a new vessel branch. Then, the blood flow velocity corresponding to the newly added vessel segment is calculated through step S103.

[0071] S103, when the second vessel centerline does not include a new vessel branch compared to the first vessel centerline, determining the blood flow velocity corresponding to the newly added vessel segment in the second vessel centerline based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image.

[0072] It should be noted that the newly added vessel segment refers to the vessel segment newly added in the second vessel centerline compared to the first vessel centerline.

[0073] For the above step S103, in a specific implementation, when the second vessel centerline does not include a new vessel branch compared to the first vessel centerline, the blood flow velocity corresponding to the newly added vessel segment in the second vessel centerline is determined based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image.

[0074] Specifically, for the above step S103, the blood flow velocity corresponding to the newly added vessel segment in the second vessel centerline is determined based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image, including:

[0075] Step 1031, determine the distance between each center point in the second vessel centerline and the vessel endpoint of the first vessel centerline, determine the center point in the second vessel centerline closest to the vessel endpoint of the first vessel centerline as the first center point, and take the vessel centerline between the first center point and the vessel endpoint of the second vessel centerline as the new vessel segment.

[0076] For the above step 1031, in specific implementation, first determine the vessel endpoint of the first vessel centerline in the centerline mapping image. Generally, the catheter of angiography tends to enter the image through the edge of the angiography image, so the starting point of the vessel centerline is closer to the edge of the angiography image, and as the vessel extends, the endpoint of the vessel centerline is farther away from the edge of the angiography image. Therefore, take the endpoint of the first vessel centerline farther away from the edge of the centerline mapping image as the vessel endpoint of the first vessel centerline. Then calculate the distance between each center point in the second vessel centerline and the vessel endpoint of the first vessel centerline, and determine the center point in the second vessel centerline closest to the vessel endpoint of the first vessel centerline as the first center point. After the first center point is determined, take the vessel centerline between the first center point and the vessel endpoint of the second vessel centerline as the new vessel segment. The determination method of the vessel endpoint of the second vessel centerline is the same as the determination method of the vessel endpoint of the first vessel centerline, which will not be described here. Specifically, the center point closest to the vessel endpoint of the first vessel centerline is determined by the following two formulas:

[0077]

[0078]

[0079] wherein the first vessel centerline is M, the number of center points in the first vessel centerline is m, M = {M0, M1, M2,..., Mm}, Mm represents the vessel endpoint of the first vessel centerline M, Mm = (x Mm ,y Mm ) represents the coordinates of the vessel endpoint of the first vessel centerline M in the centerline mapping image. The second vessel centerline is N, the number of center points in the second catheter centerline is n, N = {N0, N1, N2,..., Nn}. N k k represents the kth center point in the second vessel centerline, (x Nk ,y Nk ) represents the coordinates of the kth center point in the second vessel centerline in the centerline mapping image, N i represents the first center point.

[0080] Step 1032, determining a blood vessel starting point of the second blood vessel centerline from each center point in the second blood vessel centerline, and calculating a first length from the blood vessel starting point to the first center point by using the coordinates of other center points between the blood vessel starting point and the first center point in the centerline mapping image, and taking the first length as a previous frame blood vessel length.

[0081] It should be noted that the previous frame blood vessel length refers to the length of the filled blood vessel segment in the frame number corresponding to the first angiogram image.

[0082] For the above step 1032, in specific implementation, the blood vessel starting point of the second blood vessel centerline is determined from each center point in the second blood vessel centerline, and the first length from the blood vessel starting point to the first center point is calculated by using the coordinates of other center points between the blood vessel starting point and the first center point in the centerline mapping image, and the first length is taken as the previous frame blood vessel length. Specifically, the first length is calculated by the following two formulas:

[0083]

[0084]

[0085] Wherein, L0 represents the previous frame blood vessel length, and the above formulas are to calculate the Euclidean distance between N0 point and the next center point point by point, and then accumulate until N i point is reached.

[0086] Step 1033, calculating a second length of the second blood vessel centerline based on the coordinates of each center point in the second blood vessel centerline in the centerline mapping image, and taking the second length as a current frame blood vessel length.

[0087] It should be noted that the current frame blood vessel length refers to the length of the filled blood vessel segment in the frame number corresponding to the second angiogram image.

[0088] For the above step 1033, in specific implementation, the second length of the second blood vessel centerline is calculated based on the coordinates of each center point in the second blood vessel centerline in the centerline mapping image, and the second length is taken as the current frame blood vessel length. Specifically, the second length is calculated by the following formula:

[0089]

[0090] Wherein, L1 represents the current frame blood vessel length.

[0091] Step 1034, determine the difference between the current frame blood vessel length and the previous frame blood vessel length as a length change value, and the quotient of the length change value and the contrast image frame rate as the blood flow velocity corresponding to the new blood vessel segment.

[0092] It should be noted that the contrast image frame rate refers to the frame rate of the contrast image, that is, the time required to take one frame of image contrast. Here, the contrast image frame rate is generally 66.66 milliseconds.

[0093] For the above step 1034, in specific implementation, the difference between the current frame blood vessel length and the previous frame blood vessel length is determined as a length change value, and the quotient of the length change value and the contrast image frame rate is determined as the blood flow velocity corresponding to the new blood vessel segment according to the velocity formula. Specifically, the length change value and the blood flow velocity are calculated by the following two formulas:

[0094] ΔL = L1 - L o

[0095]

[0096] Wherein, ΔL represents the length change value, v a represents the blood flow velocity corresponding to the new blood vessel segment a, and Δt represents the contrast image frame rate.

[0097] S104, when the second blood vessel centerline has new blood vessel branches compared with the first blood vessel centerline, the blood flow velocity corresponding to each new blood vessel segment in the second blood vessel centerline is determined based on the coordinates of each center point in the first blood vessel centerline in the centerline mapping image and the coordinates of each center point in the second blood vessel centerline in the centerline mapping image.

[0098] It should be noted that the new blood vessel segment refers to each branch of the newly added branch blood vessel in the second blood vessel centerline compared with the first blood vessel centerline.

[0099] For the above step S104, in specific implementation, when the second blood vessel centerline has new blood vessel branches compared with the first blood vessel centerline, the blood flow velocity corresponding to each new blood vessel segment in the second blood vessel centerline is determined based on the coordinates of each center point in the first blood vessel centerline in the centerline mapping image and the coordinates of each center point in the second blood vessel centerline in the centerline mapping image.

[0100] Specifically, for the step S104, the blood flow velocity corresponding to each new blood vessel segment of the second blood vessel centerline is determined based on the coordinates of each center point in the first blood vessel centerline in the centerline mapping image and the coordinates of each center point in the second blood vessel centerline in the centerline mapping image, including:

[0101] In step 1041, the distance between each center point in the second blood vessel centerline and the blood vessel endpoint of the first blood vessel centerline is determined, the center point in the second blood vessel centerline closest to the blood vessel endpoint of the first blood vessel centerline is determined as the second center point, and the blood vessel centerline between the second center point and the multiple blood vessel endpoints of the second blood vessel centerline is determined as the new blood vessel branch segment.

[0102] For the step 1041, in specific implementation, first, the blood vessel endpoint of the first blood vessel centerline is determined in the centerline mapping image. Then, the distance between each center point in the second blood vessel centerline and the blood vessel endpoint of the first blood vessel centerline is determined, the center point in the second blood vessel centerline closest to the blood vessel endpoint of the first blood vessel centerline is determined as the second center point, and the blood vessel centerline between the second center point and the multiple blood vessel endpoints of the second blood vessel centerline is determined as the new blood vessel branch segment. Here, the description of how to determine the blood vessel endpoint of the first blood vessel centerline and how to determine the center point closest to the blood vessel endpoint of the first blood vessel centerline can refer to the description in the step 1031, and the same technical effects can be achieved, and thus will not be described herein.

[0103] In step 1042, the new blood vessel branch segment is divided into multiple new blood vessel segments, and the blood vessel length corresponding to each new blood vessel segment is determined.

[0104] For the step 1042, in specific implementation, the obtained new blood vessel branch segment is divided into multiple new blood vessel segments, and the blood vessel length corresponding to each new blood vessel segment is determined. Here, the description of how to determine the blood vessel length corresponding to the new blood vessel segment can refer to the description of calculating the blood vessel length in the step 1032, and the same technical effects can be achieved, and thus will not be described herein.

[0105] Specifically, for the step 1042, the new blood vessel branch segment is divided into multiple new blood vessel segments, including:

[0106] In step 10421, for each center point in the new blood vessel branch segment, the number of center points adjacent to the center point in the new blood vessel branch segment is determined.

[0107] Step 10422, when the number of center points is greater than or equal to 3, the center point is determined as a branch node.

[0108] Step 10423, based on the branch node, the blood vessel starting point in the new blood vessel branch segment, and the plurality of blood vessel ending points in the new blood vessel branch segment, a plurality of new blood vessel segments are determined.

[0109] For the above steps 10421-10422, in specific implementation, for each center point in the new blood vessel branch segment, the number of center points adjacent to the center point in the new blood vessel branch segment is determined. When the number of center points is greater than or equal to 3, the center point is determined as a branch node. Then, based on the branch node, the blood vessel starting point in the new blood vessel branch segment, and the plurality of blood vessel ending points in the new blood vessel branch segment, a plurality of new blood vessel segments are determined. Specifically, the blood vessel center line from the blood vessel starting point to the branch node in the new blood vessel branch segment is a new blood vessel segment, which is an upstream segment; the blood vessel center line from the branch node to any one of the blood vessel ending points in the new blood vessel branch segment is a new blood vessel segment, which is a downstream segment.

[0110] Step 1043, for each new blood vessel segment, based on the blood vessel length corresponding to the new blood vessel segment and the blood flow time corresponding to the new blood vessel segment, a blood flow velocity equation expression corresponding to the new blood vessel segment is determined.

[0111] It should be noted that the blood flow time refers to the time required to flow from the starting point to the ending point in a certain new blood vessel segment.

[0112] For the above step 1043, in specific implementation, for each new blood vessel segment, based on the blood vessel length corresponding to the new blood vessel segment and the blood flow time corresponding to the new blood vessel segment, a blood flow velocity equation expression corresponding to the new blood vessel segment is determined. As an example, there are three new blood vessel segments in the new blood vessel branch segment, which are c0, c1 and c2, and their lengths are c0, c1 and c2 respectively, wherein c0 is an upstream segment, and c1 and c2 are downstream segments. First, assume that the blood flow time required to flow from the starting point to the ending point of the c0 segment is t0, then the velocity of the c0 segment may be expressed as:

[0113]

[0114] wherein, represents the blood flow velocity corresponding to the c0 segment, c0 represents the blood vessel length corresponding to the c0 segment, and t0 represents the blood flow time corresponding to the c0 segment.

[0115] Since the time required for taking one frame of image is the same, the frame rate of the image is Δt, so the time from the bifurcation node to c1 and c2 is also the same, which is Δt-t0, the blood flow velocity of c1 and c2 can be expressed as:

[0116]

[0117]

[0118] wherein, represents the blood flow velocity corresponding to c1, represents the blood flow velocity corresponding to c2.

[0119] In step 1044, according to the relationship between the total flow before the vascular bifurcation and the total flow after the vascular bifurcation, the blood flow velocity solving formula corresponding to each new vascular segment is obtained by simultaneously solving the plurality of blood flow velocity equation expressions, and the blood flow velocity corresponding to each new vascular segment is solved based on the blood flow velocity solving formula corresponding to each new vascular segment.

[0120] It should be noted that the relationship between the total flow before the vascular bifurcation and the total flow after the vascular bifurcation means that the total flow before the vascular bifurcation and the total flow after the vascular bifurcation remain unchanged.

[0121] For the above step 1044, in specific implementation, according to the relationship between the total flow before the vascular bifurcation and the total flow after the vascular bifurcation, the blood flow velocity solving formula corresponding to each new vascular segment is obtained by simultaneously solving the plurality of blood flow velocity equation expressions determined in the above step 1043, and the blood flow velocity corresponding to each new vascular segment is solved based on the blood flow velocity solving formula corresponding to each new vascular segment. In fluid mechanics, the total flow before the vascular bifurcation and the total flow after the vascular bifurcation remain unchanged, which can be expressed as:

[0122] Q O = Q1+ Q2

[0123]

[0124]

[0125]

[0126] wherein Q0, Q1, Q2 respectively represent the blood flow of c0, c1 and c2, S0, S1, S2 respectively represent the average area of c0, c1 and c2, and the area can be expressed as S=πr 2, r is the radius, r0, r1, r2 respectively represent the average diameter of c0, c1 and c2 three sections. The average diameter can be obtained by the average value of the vessel diameter of each center point of the section, and then divided by 2 to get the average radius,, the vessel diameter of each point can be obtained by the following multiple alternatives: if the non-binary graph is used as the "feature map", the two gradient maxima perpendicular to the direction of the vessel center line are used as the two edges of the vessel, and the Euclidean distance of the two edges is calculated as the diameter of the vessel; if the binary graph is used as the "feature map", the two foreground (pixel value is 1) edges perpendicular to the direction of the vessel center line are used, and the Euclidean distance of the two edges is calculated as the diameter of the vessel. At this time, there are four unknowns t0, and And the simultaneous multiple blood flow velocity equation expressions are as follows:

[0127]

[0128]

[0129]

[0130]

[0131] Among them, in addition to t0, and , the others are known parameters, and the blood flow velocity solving formula corresponding to each new blood vessel segment can be solved:

[0132]

[0133]

[0134]

[0135] Based on the blood flow velocity solving formula corresponding to each new blood vessel segment, the blood flow velocity corresponding to each new blood vessel segment can be solved.

[0136] Specifically, according to the blood flow velocity determination method provided by the application, after determining the blood flow velocity corresponding to the new blood vessel segment in the second blood vessel center line, or after determining the blood flow velocity corresponding to each new blood vessel segment in the second blood vessel center line, the determination method further comprises:

[0137] Taking the second contrast image as the first contrast image, and returning to execute the step of taking the next frame contrast image adjacent to the first contrast image in the blood vessel contrast video as the second contrast image until there is no next frame contrast image adjacent to the first contrast image in the blood vessel contrast video.

[0138] After the blood flow velocity of the new blood vessel segment in the second angiography image in the angiography video is calculated, the blood flow velocity of the new blood vessel segment in the next frame of angiography image adjacent to the second angiography image needs to be calculated, and the blood flow velocity of the new blood vessel segment in each frame of angiography image in the angiography video is obtained by repeatedly calculating in this way. For the above steps, in the specific implementation, the second angiography image is taken as the first angiography image, and the step of taking the next frame of angiography image adjacent to the first angiography image in the angiography video as the second angiography image in step S101 is executed again until there is no next frame of angiography image adjacent to the first angiography image in the angiography video. In this way, after the blood flow velocity of each new blood vessel segment in the angiography video is calculated, the blood flow velocity is integrated into the overall blood vessel structure tree to obtain the global blood flow velocity.

[0139] The method for determining blood flow velocity provided by the embodiments of the present application first acquires an angiography video, takes a first frame of angiography image with a blood vessel image in the angiography video as a first angiography image, and takes a next frame of angiography image adjacent to the first angiography image in the angiography video as a second angiography image. Then, a first blood vessel center line in the first angiography image and a second blood vessel center line in the second angiography image are determined, the first blood vessel center line in the first angiography image is mapped into the second angiography image to obtain a center line mapping image, when there is no new blood vessel branch in the second blood vessel center line compared with the first blood vessel center line, the blood flow velocity corresponding to the new blood vessel segment in the second blood vessel center line is determined based on the coordinates of each center point in the first blood vessel center line in the center line mapping image and the coordinates of each center point in the second blood vessel center line in the center line mapping image, and when there is a new blood vessel branch in the second blood vessel center line compared with the first blood vessel center line, the blood flow velocity corresponding to each new blood vessel segment in the second blood vessel center line is determined based on the coordinates of each center point in the first blood vessel center line in the center line mapping image and the coordinates of each center point in the second blood vessel center line in the center line mapping image.

[0140] Compared with the blood flow velocity determination method in the prior art, the present application fully utilizes the features of the angiography dynamic sequence and the constantly filling blood vessel structure by global dynamic analysis of the image in the dynamic angiography image, obtains the dynamic center line length change, and performs local flow velocity calculation according to the two strategies of no blood vessel branch and blood vessel branch, which can adapt to complex blood vessel structures and improve the accuracy and efficiency of blood flow velocity calculation.

[0141] Please refer to Figure 2 、 Figure 3 , Figure 2Fig. 1 is a structural schematic diagram of a blood flow velocity determination device provided by an embodiment of the present application, Figure 3 Fig. 2 is another structural schematic diagram of a blood flow velocity determination device provided by an embodiment of the present application. As shown in Fig. 2, the determination device 200 comprises: Figure 2

[0142] an angiography image acquisition module 201 configured to acquire an angiography video, and take a first frame angiography image with a blood vessel image in the angiography video as a first angiography image, and take a next frame angiography image adjacent to the first angiography image in the angiography video as a second angiography image;

[0143] a centerline mapping image determination module 202 configured to determine a first blood vessel centerline in the first angiography image and a second blood vessel centerline in the second angiography image, and map the first blood vessel centerline in the first angiography image to the second angiography image to obtain a centerline mapping image;

[0144] a first blood flow velocity determination module 203 configured to, when the second blood vessel centerline has no new blood vessel branch compared with the first blood vessel centerline, determine a blood flow velocity corresponding to a new blood vessel segment in the second blood vessel centerline based on coordinates of each center point in the first blood vessel centerline in the centerline mapping image and coordinates of each center point in the second blood vessel centerline in the centerline mapping image;

[0145] a second blood flow velocity determination module 204 configured to, when the second blood vessel centerline has a new blood vessel branch compared with the first blood vessel centerline, determine a blood flow velocity corresponding to each new blood vessel segment in the second blood vessel centerline based on coordinates of each center point in the first blood vessel centerline in the centerline mapping image and coordinates of each center point in the second blood vessel centerline in the centerline mapping image.

[0146] Further, after the centerline mapping image determination module 202 obtains the centerline mapping image, the centerline mapping image determination module 202 is further configured to:

[0147] map a first catheter region in the first angiography image and a second catheter region in the second angiography image to the centerline mapping image;

[0148] skeletonize the first catheter region in the centerline mapping image to obtain a first catheter centerline, and skeletonize the second catheter region in the centerline mapping image to obtain a second catheter centerline;

[0149] ​A translation vector between the first catheter centerline and the second catheter centerline is calculated, and the first catheter centerline is translated in the centerline mapping image based on the translation vector, and a centerline mapping image after centerline translation is obtained as the centerline mapping image.

[0150] Further, as shown in Figure 3 The determining apparatus 200 further includes a branch judging module 205, which is configured to determine whether a new blood vessel branch exists in the second blood vessel centerline by the following steps:

[0151] The number of first end points corresponding to the first blood vessel centerline is determined, and the number of second end points corresponding to the second blood vessel centerline is determined;

[0152] When the number of second end points is greater than the number of first end points, it is determined that the new blood vessel branch exists in the second blood vessel centerline.

[0153] Further, when the first blood flow velocity determining module 203 is configured to determine the blood flow velocity corresponding to the new blood vessel segment in the second blood vessel centerline based on the coordinates of each center point in the first blood vessel centerline in the centerline mapping image and the coordinates of each center point in the second blood vessel centerline in the centerline mapping image, the first blood flow velocity determining module 203 is further configured to:

[0154] The distance between each center point in the second blood vessel centerline and the blood vessel end point of the first blood vessel centerline is determined, the center point closest to the blood vessel end point of the first blood vessel centerline in the second blood vessel centerline is determined as a first center point, and the blood vessel centerline from the first center point to the blood vessel end point of the second blood vessel centerline is determined as the new blood vessel segment;

[0155] The blood vessel starting point of the second blood vessel centerline is determined from each center point in the second blood vessel centerline, and the first length from the blood vessel starting point to the first center point is calculated using the coordinates of other center points between the blood vessel starting point and the first center point in the second blood vessel centerline in the centerline mapping image, and the first length is determined as a previous frame blood vessel length;

[0156] The second length of the second blood vessel centerline is calculated based on the coordinates of each center point in the second blood vessel centerline in the centerline mapping image, and the second length is determined as a current frame blood vessel length;

[0157] The difference between the current frame blood vessel length and the previous frame blood vessel length is determined as a length change value, and the quotient of the length change value and the contrast image frame rate is determined as the blood flow velocity corresponding to the new blood vessel segment.

[0158] Further, when determining the blood flow velocity corresponding to each new vessel segment of the second vessel centerline based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image, the second blood flow velocity determination module 204 is further configured to:

[0159] determine the distance between each center point in the second vessel centerline and the vessel endpoint of the first vessel centerline, determine the second center point as the center point in the second vessel centerline closest to the vessel endpoint of the first vessel centerline, and determine the vessel centerline between the second center point and the multiple vessel endpoints of the second vessel centerline as the new vessel branch segment;

[0160] divide the new vessel branch segment into multiple new vessel segments and determine the vessel length corresponding to each new vessel segment;

[0161] for each new vessel segment, determine the blood flow velocity equation expression corresponding to the new vessel segment based on the vessel length corresponding to the new vessel segment and the blood flow time corresponding to the new vessel segment;

[0162] obtain the blood flow velocity solving formula corresponding to each new vessel segment according to the relationship between the total flow before the vessel bifurcation and the total flow after the vessel bifurcation, and solve the blood flow velocity corresponding to each new vessel segment based on the blood flow velocity solving formula corresponding to each new vessel segment.

[0163] Further, when dividing the new vessel branch segment into multiple new vessel segments, the second blood flow velocity determination module 204 is further configured to:

[0164] for each center point in the new vessel branch segment, determine the number of center points adjacent to the center point in the new vessel branch segment;

[0165] when the number of center points is greater than or equal to 3, determine the center point as a branch node;

[0166] determine multiple new vessel segments based on the branch node, the vessel starting point in the new vessel branch segment, and the multiple vessel endpoints in the new vessel branch segment.

[0167] Further, as Figure 3As shown, after determining the blood flow velocity corresponding to the newly added vascular segment in the second vascular centerline, or after determining the blood flow velocity corresponding to each newly added vascular segment in the second vascular centerline, the angiography image acquisition module 201 is further configured to:

[0168] The second angiography image is used as the first angiography image, and the process returns to the step of using the next frame angiography image adjacent to the first angiography image in the angiography video as the second angiography image, until there is no next frame angiography image adjacent to the first angiography image in the angiography video.

[0169] 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.

[0170] 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 the method for determining blood flow velocity in the illustrated method embodiment can be found in the method embodiment for specific implementation, and will not be repeated here.

[0171] 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 the method for determining blood flow velocity in the illustrated method embodiment can be found in the method embodiment for specific implementation, and will not be repeated here.

[0172] 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.

[0173] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other manners. The described device embodiments are merely schematic, and for example, the division of the units is only a logical function division, and there can be another division manner in actual implementation; for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be electric, mechanical or in other forms.

[0174] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purposes of the embodiments.

[0175] In addition, each functional unit in the various embodiments of the present application can be integrated in one processing unit, or each unit can be a physically separate unit, or two or more units can be integrated in one unit.

[0176] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a non-volatile computer readable storage medium executable by a processor. Based on this understanding, the technical solutions of the present application essentially or the parts that make contributions to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0177] It should be noted that: similar reference numerals and letters in the following drawings represent similar items, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0178] Finally, it should be noted that the above-described embodiments are merely specific embodiments of the present application, which are used to illustrate the technical solutions of the present application, but not to limit the same. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that any skilled person in the art can still modify or easily think of changes to the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some of the technical features, within the technical scope disclosed by the present application. The modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for determining blood flow velocity, characterized in that, The determination method includes: Acquire angiography video, and take the first frame of angiography image containing vascular images in the angiography video as the first angiography image, and take the next frame of angiography image adjacent to the first angiography image in the angiography video as the second angiography image. The center line of the first blood vessel in the first angiography image and the center line of the second blood vessel in the second angiography image are determined, and the center line of the first blood vessel in the first angiography image is mapped onto the second angiography image to obtain a center line mapping image; When the second vessel centerline does not contain any new vessel branches compared to the first vessel centerline, the blood flow velocity corresponding to the newly added vessel segment in the second vessel centerline is determined based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image. When the second vessel centerline has new vessel branches compared to the first vessel centerline, the blood flow velocity corresponding to each newly added vessel segment in the second vessel centerline is determined based on the coordinates of each center point in the first vessel centerline in the centerline mapping image and the coordinates of each center point in the second vessel centerline in the centerline mapping image. After obtaining the centerline mapping image, the determination method further includes: Map the first catheter region in the first contrast image and the second catheter region in the second contrast image onto the centerline mapping image; In the centerline mapping image, the first catheter region is skeletonized to obtain the first catheter centerline, and the second catheter region is skeletonized to obtain the second catheter centerline; Calculate the translation vector between the centerline of the first catheter and the centerline of the second catheter, and translate the centerline of the first catheter in the centerline mapping image based on the translation vector. The centerline mapping image obtained after translating the centerline is used as the centerline mapping image.

2. The determination method according to claim 1, characterized in that, When determining whether there are new vascular branches in the central line of the second vessel using the following steps: Determine the number of first endpoints corresponding to the first vessel centerline and the number of second endpoints corresponding to the second vessel centerline; When the number of the second endpoints is greater than the number of the first endpoints, it is determined that there is a new vascular branch in the center line of the second vessel.

3. The determination method according to claim 1, characterized in that, The step of determining the blood flow velocity corresponding to the newly added vascular segment in the second vascular centerline based on the coordinates of each center point in the first vascular centerline in the centerline mapping image and the coordinates of each center point in the second vascular centerline in the centerline mapping image includes: Determine the distance between each center point in the second vessel centerline and the end point of the first vessel centerline, determine the center point in the second vessel centerline that is closest to the end point of the first vessel centerline as the first center point, and take the vessel centerline from the first center point to the end point of the second vessel centerline as the newly added vessel segment. The origin of the second blood vessel centerline is determined from each center point in the second blood vessel centerline, and the first length from the origin of the blood vessel to the first center point is calculated in the centerline mapping image using the coordinates of other center points in the second blood vessel centerline between the origin of the blood vessel and the first center point, and the first length is used as the blood vessel length of the previous frame. The second length of the second blood vessel centerline is calculated based on the coordinates of each center point in the centerline mapping image, and the second length is used as the blood vessel length in the current frame. The difference between the current frame vessel length and the previous frame vessel length is determined as the length change value, and the quotient of the length change value and the angiographic image frame rate is used as the blood flow velocity corresponding to the newly added vessel segment.

4. The determination method according to claim 1, characterized in that, The step of determining the blood flow velocity corresponding to each newly added vascular segment in the second vascular centerline based on the coordinates of each center point in the first vascular centerline in the centerline mapping image and the coordinates of each center point in the second vascular centerline in the centerline mapping image includes: Determine the distance between each center point in the second vessel centerline and the vessel endpoint of the first vessel centerline, determine the center point in the second vessel centerline that is closest to the vessel endpoint of the first vessel centerline as the second center point, and take the vessel centerline between the second center point and multiple vessel endpoints of the second vessel centerline as the newly added vessel branch segment. The newly added vascular branch segment is divided into multiple newly added vascular segments, and the vascular length corresponding to each newly added vascular segment is determined. For each newly added blood vessel segment, the blood flow velocity equation expression corresponding to the newly added blood vessel segment is determined based on the blood vessel length and blood flow time corresponding to the newly added blood vessel segment. Based on the relationship between the total flow rate before and after the bifurcation of the blood vessel, multiple blood flow velocity equations are combined to obtain the blood flow velocity solution formula for each newly added blood vessel segment. Based on the blood flow velocity solution formula for each newly added blood vessel segment, the blood flow velocity for each newly added blood vessel segment is calculated.

5. The determination method according to claim 4, characterized in that, The step of dividing the newly added vascular branch segment into multiple newly added vascular segments includes: For each center point in the newly added vascular branch segment, determine the number of other center points adjacent to that center point in the newly added vascular branch segment; When the number of center points is greater than or equal to 3, the center point is determined as a branch node; Based on the branch node, the origin of the newly added blood vessel branch segment, and multiple end points of the newly added blood vessel branch segment, multiple newly added blood vessel segments are determined.

6. The determination method according to claim 1, characterized in that, After determining the blood flow velocity corresponding to the newly added vascular segment in the second vascular centerline, or after determining the blood flow velocity corresponding to each newly added vascular segment in the second vascular centerline, the determination method further includes: The second angiography image is used as the first angiography image, and the process returns to the step of using the next frame angiography image adjacent to the first angiography image in the angiography video as the second angiography image, until there is no next frame angiography image adjacent to the first angiography image in the angiography video.

7. A device for determining blood flow velocity, characterized in that, The determining device includes: The angiography image acquisition module is used to acquire angiography video, and take the first frame angiography image with vascular images in the angiography video as the first angiography image, and take the next frame angiography image adjacent to the first angiography image in the angiography video as the second angiography image. The centerline mapping image determination module is used to determine the first blood vessel centerline in the first angiography image and the second blood vessel centerline in the second angiography image, and to map the first blood vessel centerline in the first angiography image onto the second angiography image to obtain a centerline mapping image; The first blood flow velocity determination module is used to determine the blood flow velocity corresponding to the newly added blood vessel segment in the second blood vessel centerline based on the coordinates of each center point in the first blood vessel centerline in the centerline mapping image and the coordinates of each center point in the second blood vessel centerline in the centerline mapping image when there are no new blood vessel branches in the second blood vessel centerline compared with the first blood vessel centerline. The second blood flow velocity determination module is used to determine the blood flow velocity corresponding to each newly added blood vessel segment in the second blood vessel centerline based on the coordinates of each center point in the first blood vessel centerline in the centerline mapping image and the coordinates of each center point in the second blood vessel centerline in the centerline mapping image when there are new blood vessel branches in the second blood vessel centerline compared with the first blood vessel centerline. After obtaining the centerline mapping image, the centerline mapping image determination module is further configured to: Map the first catheter region in the first contrast image and the second catheter region in the second contrast image onto the centerline mapping image; In the centerline mapping image, the first catheter region is skeletonized to obtain the first catheter centerline, and the second catheter region is skeletonized to obtain the second catheter centerline; Calculate the translation vector between the centerline of the first catheter and the centerline of the second catheter, and translate the centerline of the first catheter in the centerline mapping image based on the translation vector. The centerline mapping image obtained after translating the centerline is used as the centerline mapping image.

8. An electronic device, characterized in that, include: The device includes a processor, a memory, and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor communicates with the memory via the bus, and the machine-readable instructions are executed by the processor to perform the steps of the method for determining blood flow velocity 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 the method for determining blood flow velocity as described in any one of claims 1 to 6.

Images