Microvascular three-dimensional imaging method and system based on ultrasonic phased array, and medium

Abstract

The invention discloses a microvessel three-dimensional imaging method based on an ultrasonic phased array, and relates to an ultrasonic imaging technology. According to the method, the three-dimensional ultrasonic sequence image can be obtained according to the ultrasonic image data obtained through multiple times of spherical wave emission operation, then the three-dimensional ultrasonic sequence image is segmented into a plurality of time-space sub-blocks, singular value decomposition is performed on all the time-space sub-blocks, contrast agent signals are extracted, and the contrast agent signals are obtained. Obtaining a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasonic sequence image according to the contrast agent signal; the method comprises the following steps: performing binarization processing on a three-dimensional contrast agent sequence image to obtain a plurality of connected domains, calculating a microbubble center point corresponding to each connected domain according to the connected domain, and finally performing microvessel three-dimensional imaging operation according to the microbubble center points. Wherein the design of each time-space sub-block can reduce the influence of great blood vessels and physiological movement on data; the three-dimensional contrast agent sequence image is subjected to binarization processing, so that the calculation amount can be reduced, the efficiency can be improved, and finally, the three-dimensional imaging of the microvessels can be efficiently and accurately realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic imaging, in particular to a microvessel three-dimensional imaging method and system based on an ultrasonic phased array, and a medium. BACKGROUND

[0002] Ultrasound localization microscopy (ULM) is a new type of ultrasonic imaging method, which indirectly depicts the vascular structure and hemodynamics by tracking the trajectory of microbubbles in the vascular network. Because the imaging spatial resolution of this technology is high, it has great clinical application value in the differentiation of benign and malignant tumors and the diagnosis and treatment of related diseases of the heart and brain circulation. ULM relies on the rapid acquisition of ultrasonic sequences to reconstruct high-resolution microvascular distribution maps of tissues. However, due to the physiological movement of the heart, it is a great challenge to obtain multiple frames of high spatiotemporal coherence ultrasonic images in a short time. Accordingly, ultrasonic super-resolution microvascular imaging technology (SR) uses ultrasonic contrast agents injected intravenously and uses ultrasonic imaging algorithms to track the flow trajectory of the contrast agents. By superimposing multiple frames of contrast agent trajectories, the microvascular morphology and calculated hemodynamic parameters can be reconstructed.

[0003] In 2024, Professor Mengxing Tang's team at Imperial College London used phased array ultrasonic super-fast imaging combined with electro-physiological equipment to collect transthoracic echocardiogram sequences to visualize myocardial microcirculation and coronary arteries. However, this microvessel three-dimensional imaging method based on ultrasonic phased array is currently limited to two-dimensional imaging of microvessels. Therefore, it is necessary to propose a new microvessel imaging method based on ultrasonic phased array to realize three-dimensional imaging of microvessels. SUMMARY

[0004] The present application provides a microvessel three-dimensional imaging method and system based on an ultrasonic phased array, and a medium, for realizing three-dimensional imaging of microvessels.

[0005] To solve the above technical problems, the present application discloses a microvessel three-dimensional imaging method based on an ultrasonic phased array in the first aspect, a two-dimensional ultrasonic phased array including a plurality of ultrasonic array elements located on the same plane, the method comprising: In a predetermined continuous time, the spherical wave emission operation is performed multiple times, each time the spherical wave emission operation includes: the two-dimensional ultrasonic phased array array emits spherical waves in turn, after each spherical wave emission, all ultrasonic array elements simultaneously receive echo data, and after coherent superposition of all echo data, ultrasonic image data is obtained, the ultrasonic image data at least includes contrast agent echo; According to the ultrasonic image data obtained by each spherical wave emission operation, a three-dimensional ultrasonic sequence image is obtained; The three-dimensional ultrasound sequence image is segmented into a plurality of spatio-temporal sub-blocks, each spatio-temporal sub-block including partial time dimension data and partial space dimension data of the three-dimensional ultrasound sequence image, and adjacent two spatio-temporal sub-blocks have partial overlapping data in the time dimension data and the space dimension data; The singular value decomposition is performed on all the spatio-temporal sub-blocks, a contrast agent signal is extracted, and a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasound sequence image is obtained according to the contrast agent signal; The three-dimensional contrast agent sequence image is subjected to a binaryzation process to obtain a plurality of connected domains, and a microbubble center point corresponding to each connected domain is calculated according to the connected domain; A microvessel three-dimensional imaging operation is performed according to the microbubble center point.

[0006] As an optional implementation, in the first aspect of the present application, the two-dimensional ultrasound phased array includes a plurality of sub-arrays located in the same plane, each sub-array includes a plurality of ultrasound array elements located in the same plane, and at least one ultrasound array element in each sub-array is determined as a reference array element; The two-dimensional ultrasound phased array emits spherical waves corresponding to different virtual point sources each time, and all the virtual point sources have a preset positional relationship so that echo data corresponding to all the virtual point sources can be focused on an imaging origin; Each time the spherical wave emission operation includes: The two-dimensional ultrasound phased array emits spherical waves corresponding to different virtual point sources in turn, and all the ultrasound array elements simultaneously receive echo data after each spherical wave emission to obtain an echo subset received by each sub-array at each virtual point source; All the reference array elements in the two-dimensional ultrasound phased array emit spherical waves corresponding to the imaging origin, and all the reference array elements simultaneously receive echo data to obtain a superimposed reference system; The echo subsets received by all the sub-arrays at each virtual point source are coherently superimposed based on the superimposed reference system to obtain ultrasound image data.

[0007] As an optional implementation, in the first aspect of the present application, the operation of emitting spherical waves by the two-dimensional ultrasound phased array each time includes: Each ultrasound array element on the two-dimensional ultrasound phased array emits an ultrasound wave at a respective preset time point, so that the ultrasound waves emitted by the two-dimensional ultrasound phased array are equivalent to spherical waves emitted from a virtual point source.

[0008] As an optional implementation, in the first aspect of the present application, a pixel point of each frame of image in the three-dimensional ultrasound sequence image is , and a time dimension corresponding to the three-dimensional ultrasound sequence image is ; And the three-dimensional ultrasound sequence image is divided into a plurality of spatio-temporal sub-blocks, and the spatial dimension data corresponding to any one spatio-temporal sub-block is The three-dimensional ultrasound sequence image is divided into a plurality of spatio-temporal sub-blocks, and the spatial dimension data corresponding to any one spatio-temporal sub-block is The time dimension data corresponding to any one spatio-temporal sub-block is ; wherein And the time dimension data and the spatial dimension data corresponding to adjacent two spatio-temporal sub-blocks have partial overlapping data.

[0009] As an optional implementation, in the first aspect of the present application, the three-dimensional imaging operation of the microbubble center point includes: Trajectory tracking is performed on the microbubble center point in each frame of three-dimensional contrast agent image, and a plurality of three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image are obtained; All the three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image are superimposed, and the three-dimensional distribution image of the microvessel is obtained.

[0010] As an optional implementation, in the first aspect of the present application, the trajectory tracking is performed on the microbubble center point in each frame of three-dimensional contrast agent image, and a plurality of three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image are obtained; A plurality of feature pixel points in each frame of three-dimensional contrast agent image are identified, and the feature pixel points are pixel points located at the contour edge of the microvessel; A predetermined number of adjacent pixel points around each feature pixel point are obtained, and for each feature pixel point, a feature pattern is fitted according to the feature pixel point and the adjacent pixel points corresponding to the feature pixel point; For each feature pattern in each frame of three-dimensional contrast agent image, a similar feature pattern corresponding to each feature pattern is determined in the adjacent frame of three-dimensional contrast image corresponding to the frame of three-dimensional contrast image; According to the similar feature pattern corresponding to each feature pattern in all frames of three-dimensional contrast agent image, the trajectory corresponding to each feature point is determined.

[0011] The second aspect of the present application discloses an ultrasound imaging system, which comprises: A two-dimensional ultrasound phased array comprising a plurality of ultrasound array elements located in the same plane, the two-dimensional ultrasound phased array being used to: In a predetermined continuous time, a plurality of spherical wave transmission operations are performed, each of which includes: the two-dimensional ultrasound phased array sequentially emits spherical waves, after each spherical wave transmission, all ultrasound array elements simultaneously receive echo data, and after the coherent superposition of all echo data, ultrasound image data is obtained, the ultrasound image data at least including contrast agent echoes; A host computer, which is in communication connection with the two-dimensional ultrasonic phased array, is used for: According to the ultrasonic image data obtained by each spherical wave emission operation, a three-dimensional ultrasonic sequence image is obtained. The three-dimensional ultrasonic sequence image is divided into a plurality of spatio-temporal sub-blocks, each spatio-temporal sub-block including partial time dimension data and partial space dimension data of the three-dimensional ultrasonic sequence image, and adjacent two spatio-temporal sub-blocks have partial overlapping data corresponding to the time dimension data and the space dimension data. The singular value decomposition module is configured to perform singular value decomposition on all the spatio-temporal sub-blocks, extract contrast agent signals, and obtain a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasonic sequence image according to the contrast agent signals. The center point positioning module is configured to perform binaryzation processing on the three-dimensional contrast agent sequence image to obtain a plurality of connected domains, and calculate a microbubble center point corresponding to each connected domain according to the connected domain. The imaging module is configured to perform microvessel three-dimensional imaging operation according to the microbubble center point.

[0012] The third aspect of the present application discloses a microvessel three-dimensional imaging device based on an ultrasonic phased array, the two-dimensional ultrasonic phased array including a plurality of ultrasonic array elements located on the same plane, and the device includes: The transmission module is configured to control the execution of spherical wave emission operation multiple times within a preset continuous time. Each time the spherical wave emission operation includes: controlling the two-dimensional ultrasonic phased array to emit spherical waves in turn, receiving echo data simultaneously after each spherical wave emission, and obtaining ultrasonic image data by coherently superimposing all echo data, wherein the ultrasonic image data at least includes contrast agent echo. The signal receiving and collecting module is configured to obtain a three-dimensional ultrasonic sequence image according to the ultrasonic image data obtained by each spherical wave emission operation. The data segmentation module is configured to divide the three-dimensional ultrasonic sequence image into a plurality of spatio-temporal sub-blocks, each spatio-temporal sub-block including partial time dimension data and partial space dimension data of the three-dimensional ultrasonic sequence image, and adjacent two spatio-temporal sub-blocks having partial overlapping data corresponding to the time dimension data and the space dimension data. The singular value decomposition module is configured to perform singular value decomposition on all the spatio-temporal sub-blocks, extract contrast agent signals, and obtain a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasonic sequence image according to the contrast agent signals. The center point positioning module is configured to perform binaryzation processing on the three-dimensional contrast agent sequence image to obtain a plurality of connected domains, and calculate a microbubble center point corresponding to each connected domain according to the connected domain. The imaging module is configured to perform microvessel three-dimensional imaging operation according to the microbubble center point.

[0013] As an optional implementation, in the third aspect of the present application, the two-dimensional ultrasonic phased array includes a plurality of sub-arrays located in the same plane, each of the sub-arrays includes a plurality of ultrasonic array elements located in the same plane, wherein at least one ultrasonic array element in each of the sub-arrays is determined as a reference array element; The two-dimensional ultrasonic phased array emits a spherical wave corresponding to a different virtual point source each time, and all the virtual point sources have a preset positional relationship, so that echo data corresponding to all the virtual point sources can be focused on the imaging origin; And each time the spherical wave emission operation includes: Controlling the two-dimensional ultrasonic phased array to emit spherical waves corresponding to different virtual point sources in turn, and receiving echo data by all the ultrasonic array elements simultaneously after each spherical wave emission to obtain a received echo subset of each sub-array at each virtual point source; All the reference array elements of the two-dimensional ultrasonic phased array emit a spherical wave corresponding to the imaging origin, and all the reference array elements receive echo data simultaneously to obtain a superimposed reference system; Coherently superimposing the received echo subset of all the sub-arrays at each virtual point source based on the superimposed reference system to obtain ultrasonic image data.

[0014] As an optional implementation, in the third aspect of the present application, the operation of emitting a spherical wave by the two-dimensional ultrasonic phased array each time includes: Each ultrasonic array element on the two-dimensional ultrasonic phased array emits an ultrasonic wave at a respective preset time point, so that the ultrasonic wave emitted by the two-dimensional ultrasonic phased array is equivalent to a spherical wave emitted from a virtual point source.

[0015] As an optional implementation, in the third aspect of the present application, each pixel point of each frame of image in the three-dimensional ultrasonic sequence image is , and the time dimension corresponding to the three-dimensional ultrasonic sequence image is ; And the specific operation mode of the data segmentation module for segmenting the three-dimensional ultrasonic sequence image into a plurality of spatio-temporal sub-blocks includes: Segmenting the three-dimensional ultrasonic sequence image into a plurality of spatio-temporal sub-blocks, the spatial dimension data corresponding to any one spatio-temporal sub-block is , and the time dimension data corresponding to any one spatio-temporal sub-block is ; wherein , and the time dimension data and the spatial dimension data corresponding to adjacent two spatio-temporal sub-blocks have partial overlapping data.

[0016] As an optional implementation, in the third aspect of the present application, the imaging module performs microvessel three-dimensional imaging operation according to the microbubble center point, including: Trajectory tracking is performed on the microbubble center points in each frame of the three-dimensional contrast agent image to obtain a plurality of three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence images; All the three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence images are superimposed to obtain the three-dimensional microvascular distribution image.

[0017] As an optional implementation, in the third aspect of the present application, the specific operation mode of the imaging module for trajectory tracking of the microbubble center points in each frame of the three-dimensional contrast agent image includes: Identifying a plurality of feature pixel points in each frame of the three-dimensional contrast agent image, the feature pixel points being pixel points located on the contour edge of the microvessel; Obtaining a preset number of adjacent pixel points around each feature pixel point, and for each feature pixel point, fitting a feature pattern according to the feature pixel point and the adjacent pixel points corresponding to the feature pixel point; For each feature pattern in each frame of the three-dimensional contrast agent image, a similar feature pattern corresponding to each feature pattern is determined in the adjacent frame of the three-dimensional contrast agent image corresponding to the frame of the three-dimensional contrast agent image; According to the similar feature patterns corresponding to each feature pattern in all frames of the three-dimensional contrast agent image, a trajectory corresponding to each feature point is determined.

[0018] The fourth aspect of the present application discloses a microvascular three-dimensional imaging system based on an ultrasonic phased array, the system comprising: A memory storing executable program codes; A processor coupled with the memory; The processor calls the executable program codes stored in the memory to execute the microvascular three-dimensional imaging method based on the ultrasonic phased array disclosed in the first aspect of the present application.

[0019] The fifth aspect of the present application discloses a computer storage medium storing computer instructions, the computer instructions being called to execute the microvascular three-dimensional imaging method based on the ultrasonic phased array disclosed in the first aspect of the present application.

[0020] Compared with the prior art, the microvessel three-dimensional imaging method based on the ultrasonic phased array of the application can obtain a three-dimensional ultrasonic sequence image according to ultrasonic image data obtained through multiple spherical wave emission operations, then divide the three-dimensional ultrasonic sequence image into multiple space-time subblocks, perform singular value decomposition on all the space-time subblocks, extract contrast agent signals, and obtain a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasonic sequence image according to the contrast agent signals; the three-dimensional contrast agent sequence image is subjected to binaryzation processing to obtain multiple connected domains, the center point of the microbubble corresponding to each connected domain is calculated according to the connected domain, and finally, microvessel three-dimensional imaging operation is performed according to the center point of the microbubble. The scheme of superimposing multiple three-dimensional spherical waves improves the detection range without losing the detection accuracy; the design of each space-time subblock can reduce the influence of large blood vessels and physiological motion on data, and the existence of overlapping data between adjacent space-time subblocks can reflect the continuity of blood flow, thus retaining the continuity and internal relationship of the ultrasonic sequence image; the binaryzation processing of the three-dimensional contrast agent sequence image can reduce the amount of calculation and improve the efficiency. Ultimately, the embodiment of the application can efficiently and accurately realize three-dimensional imaging of microvessels. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0022] Figure 1 is a flowchart of a microvessel three-dimensional imaging method based on an ultrasonic phased array disclosed by the embodiment of the application; Figure 2 is a schematic diagram showing different point sources corresponding to different detection ranges, taking two dimensions as an example; Figure 3 is a two-dimensional phased array schematic diagram disclosed by the embodiment of the application; Figure 4 is a spherical wave detection range schematic diagram of a single virtual point source disclosed by the embodiment of the application; Figure 5 is a spatial relationship diagram between a single point source and a two-dimensional ultrasonic phased array disclosed by the embodiment of the application; Figure 6 is a schematic diagram of detecting myocardium using a two-dimensional micro ultrasonic phased array disclosed by the embodiment of the application; Figure 7 is a structure schematic diagram of a microvessel three-dimensional imaging system based on an ultrasonic phased array disclosed by the embodiment of the application. DETAILED DESCRIPTION

[0023] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings 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 of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0024] The terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product, or end including a series of steps or units is not limited to the listed steps or units, but can optionally further include steps or units not listed, or can optionally further include other steps or units inherent to the process, method, product, or end.

[0025] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor does it necessarily refer to a separate or alternative embodiment in isolation from other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] Embodiment one Please refer to Figure 1 , Figure 1 is a flowchart of a microvessel three-dimensional imaging method based on an ultrasonic phased array according to an embodiment of the present application. In this embodiment, Figure 1 The microvessel three-dimensional imaging method based on an ultrasonic phased array described above can be integrated in a certain three-dimensional imaging device, and the three-dimensional imaging device can be integrated in a cloud server or a local server. Figure 1 The microvessel three-dimensional imaging method based on an ultrasonic phased array described above can also be integrated in a host computer, which is in communication connection with a two-dimensional ultrasonic phased array. As Figure 1 The microvessel three-dimensional imaging method based on an ultrasonic phased array described above can include the following operations: Step 101: performing a spherical wave emission operation multiple times within a preset continuous time.

[0027] In the embodiments of the present application, each spherical wave emission operation can include: a two-dimensional ultrasonic phased array sequentially emits spherical waves, all ultrasonic array elements simultaneously receive echo data after each spherical wave emission, and ultrasonic image data is obtained after coherent superposition of all echo data, the ultrasonic image data can at least include contrast agent echoes.

[0028] In the embodiment of the present application, the two-dimensional ultrasonic phased array can include a plurality of ultrasonic array elements located on the same plane. In each time of transmitting ultrasonic waves, if all the ultrasonic array elements in the two-dimensional ultrasonic phased array emit ultrasonic waves at the same time, the ultrasonic waves emitted by the entire ultrasonic phased array are three-dimensional plane waves, and the wave front of the three-dimensional plane waves spreads in a planar manner. If each ultrasonic array element in the two-dimensional ultrasonic phased array emits ultrasonic waves at different preset times, different types of ultrasonic waves can be emitted, such as three-dimensional plane waves propagating at an angle, three-dimensional spherical waves with a point as a point source, and the like. In the embodiment of the present application, each ultrasonic array element in the two-dimensional ultrasonic phased array is selected to emit ultrasonic waves at different preset times, so that three-dimensional spherical waves with a point as a point source are emitted. The spherical waves have the advantages of wide detection range and focusing capability.

[0029] For the spherical waves, although the detection range of the three-dimensional spherical waves is improved, the corresponding accuracy is reduced. To solve this problem, the present application proposes a scheme of coherently superimposing a plurality of three-dimensional spherical waves, that is, the detection range is improved, and the detection accuracy is not lost. For example, each spherical wave corresponds to a certain central line direction, and the two-dimensional ultrasonic phased array emits the spherical waves in sequence, which can emit the spherical waves in sequence along different central line directions, so as to cover a larger detection space and ensure a certain detection density, and fine detection can be realized. As shown in FIG. 4, taking the two-dimensional spherical waves emitted by the one-dimensional ultrasonic phased array as an example, the spherical wave corresponding to the first point source and the spherical wave corresponding to the second point source detect different directions respectively, and the combination of the two corresponds to a wider detection direction. The above principle applied to the three-dimensional spherical waves emitted by the two-dimensional ultrasonic phased array also has the same conclusion. Figure 2

[0030] Step 102: obtaining a three-dimensional ultrasonic sequence image according to the ultrasonic image data obtained in each spherical wave transmission operation.

[0031] In the preset continuous time, the spherical wave transmission operation is performed multiple times, so as to obtain a plurality of frames of three-dimensional ultrasonic images of the contrast agent flowing with the blood in sequence. The plurality of frames of three-dimensional ultrasonic images constitute a three-dimensional ultrasonic sequence image. The sequence image not only contains the ultrasonic echoes of the contrast agent, but also contains the information of the contrast agent flowing with the blood, thereby providing more reliable data support for subsequent processing.

[0032] Step 103: dividing the three-dimensional ultrasonic sequence image into a plurality of spatio-temporal sub-blocks.

[0033] In the optional embodiment, each spatio-temporal sub-block can include part of the time dimension data and part of the space dimension data of the three-dimensional ultrasonic sequence image, and the time dimension data and the space dimension data corresponding to adjacent two spatio-temporal sub-blocks have part of the overlapping data.

[0034] ​Due to the different spatio-temporal coherence of tissue and flowing contrast agent signals, tissue corresponds to high spatio-temporal coherence signals in the image sequence, while contrast agent signals correspond to low spatio-temporal coherence signals, so they can be separated by singular value decomposition.

[0035] In ultrasonic imaging, tissue and flowing contrast agent (such as microbubbles) exhibit different spatio-temporal characteristics in the image sequence: Tissue: Due to relatively small structural motion, it changes little between consecutive image frames, showing high spatio-temporal coherence (strong correlation in time and space).

[0036] Contrast agent: With rapid blood flow, its position and intensity change dramatically in the time sequence, showing low spatio-temporal coherence (weak correlation in time and space).

[0037] This difference provides the basis for separating the two types of signals using mathematical tools such as singular value decomposition.

[0038] In embodiments of the present application, if singular value decomposition is directly performed on the ultrasonic sequence images, it is easily affected by large blood vessels and physiological motion, and part of the microvascular information may be lost. To solve this problem, the three-dimensional ultrasonic sequence images are divided into multiple spatio-temporal sub-blocks in embodiments of the present application, wherein each spatio-temporal sub-block can include part of the time dimension data and part of the spatial dimension data of the three-dimensional ultrasonic sequence images, and there is part of the overlapping data between the time dimension data and the spatial dimension data corresponding to adjacent two spatio-temporal sub-blocks. After blocking, the influence of large blood vessels and physiological motion on the data can be reduced, and the continuity of blood flow can be reflected by the overlapping data between adjacent spatio-temporal sub-blocks, thus preserving the continuity and internal relationship of the ultrasonic sequence images.

[0039] Step 104, singular value decomposition is performed on all spatio-temporal sub-blocks to extract contrast agent signals, and a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasonic sequence image is obtained according to the contrast agent signals.

[0040] Singular value decomposition (SVD) is a linear algebra method that decomposes a matrix into three sub-matrices: (left singular vector): represents the spatial characteristics (such as the relationship between pixel positions). (singular value matrix): diagonal matrix, singular values are arranged in descending order, representing the principal component energy of the data. (right singular vector): represents the temporal characteristics (such as the relationship between frame changes). The core idea is to extract the main mode (corresponding to large singular values) and the secondary mode (corresponding to small singular values) in the data through SVD, thereby separating signals of different coherence.

[0041] In the embodiment of the present application, the high coherence signal (tissue): presents slow change or periodic pattern in time series, and the energy is concentrated in a few principal components (large singular values). The low coherence signal (contrast agent): presents fast random motion, and the energy is dispersed in multiple small singular values. The components corresponding to the singular vectors present high frequency and unstructured characteristics.

[0042] Therefore, the embodiment of the present application can perform singular value decomposition on all spatiotemporal sub-blocks, extract three-dimensional contrast agent signals, and then obtain a three-dimensional contrast agent sequence image corresponding to a three-dimensional ultrasound sequence image according to the three-dimensional contrast agent signals. The three-dimensional ultrasound sequence image is composed of multiple three-dimensional ultrasound images of consecutive frames, and contains the echo conditions of the contrast agent in the microvessels within a preset continuous time. In steps 103-104, the echo conditions of the contrast agent in the microvessels within the preset continuous time are extracted from the three-dimensional ultrasound sequence image in a series of ways to obtain the three-dimensional contrast agent sequence image.

[0043] In step 105, the three-dimensional contrast agent sequence image is subjected to binaryzation processing to obtain multiple connected domains, and the microbubble center point corresponding to each connected domain is calculated.

[0044] In the embodiment of the present application, the three-dimensional contrast agent sequence image is subjected to binaryzation processing, and the pixel value is only 0 or 1, so that the microbubble signal in the contrast agent is separately displayed. Because the echo signal of the contrast agent microbubble is much stronger than the echo of blood vessels and other tissues, the echo of the contrast agent microbubble is like a bright spot, which is a spatial ideal scattering point in the three-dimensional ultrasound image. The diameter of the microbubble is 1-3 microns, which can be regarded as an ideal scattering point in the imaging space, and the ultrasound signal thereof can be considered as a system point spread function, which is generally considered as a three-dimensional Gaussian model.

[0045] The positioning of the contrast agent center point is the core of the imaging algorithm. The current positioning methods based on the Gaussian model of the point spread function and the radial symmetry require a large number of image frames, a long acquisition time and a long post-processing time. In the embodiment of the present application, a threshold can be set in the binaryzation process, all pixels with a pixel value greater than the threshold are uniformly modified to 1, and all pixels with a pixel value less than the threshold are uniformly modified to 0. Finally, multiple connected domains can be obtained from the three-dimensional contrast agent sequence image, each connected domain corresponds to a three-dimensional microbubble echo, and the microbubble center point is determined according to the connected domain, for example, the centroid of the connected domain is calculated as the microbubble center point by using the centroid algorithm. The scheme of the embodiment of the present application can reduce the calculation amount and improve the efficiency.

[0046] In step 106, a microvessel three-dimensional imaging operation is performed according to the microbubble center point.

[0047] In the embodiments of the present invention, the distribution of microbubbles can indirectly represent the distribution of microvessels, and the three-dimensional microbubble distribution represents the three-dimensional microvessel distribution. For example, the center points of all microbubbles can be fitted and superimposed on each other to obtain the three-dimensional distribution of microvessels. On this basis, the velocity of the center points of microbubbles can also be calculated to obtain the blood flow velocity.

[0048] It can be seen that the three-dimensional microvessel imaging method based on ultrasonic phased array in the embodiments of the present invention can obtain three-dimensional ultrasonic sequence images according to the ultrasonic image data obtained by multiple spherical wave emission operations, then divide the three-dimensional ultrasonic sequence images into multiple spatio-temporal sub-blocks, perform singular value decomposition on all spatio-temporal sub-blocks, extract the contrast agent signals, and obtain the three-dimensional contrast agent sequence images corresponding to the three-dimensional ultrasonic sequence images according to the contrast agent signals; perform binary processing on the three-dimensional contrast agent sequence images to obtain multiple connected domains, calculate the center points of microbubbles corresponding to each connected domain according to each connected domain, and finally perform three-dimensional microvessel imaging operations according to the center points of microbubbles. Among them, the imaging scheme of coherently superimposing multiple three-dimensional spherical waves not only improves the detection breadth but also does not lose the detection accuracy; the design of each spatio-temporal sub-block can reduce the influence of large blood vessels and physiological movements on the detection of microvessels, and there are overlapping data in adjacent spatio-temporal sub-blocks, which can effectively reduce the interference of random noise signals on blood vessel imaging; performing binary processing on the three-dimensional contrast agent sequence images can reduce the amount of calculation and improve the efficiency. Finally, the embodiments of the present invention can efficiently and accurately implement three-dimensional imaging of microvessels.

[0049] In the embodiments of the present invention, obtaining ultrasonic image data by coherently superimposing all echo data will bring a certain amount of calculation. For example, for echo data with the center line directions of four beams corresponding to the left front, right front, upper front, and lower front respectively, for the ultrasonic image data at the overlapping part, it is necessary to first identify it and then perform data combination based on the coherent relationship.

[0050] To solve the technical problem of large calculation amount in the coherent superposition process, in an optional embodiment, a two-dimensional ultrasonic phased array may include multiple sub-arrays located on the same plane, and each sub-array may include multiple ultrasonic array elements located on the same plane. Among them, at least one ultrasonic array element on each sub-array is determined as a reference array element.

[0051] In this optional embodiment, the following is an example: As Figure 3 shown, for some special application scenarios, such as for special miniature two-dimensional phased arrays for intracardiac ultrasonic imaging, a sub-array scheme can be adopted. Specifically, for an 8×8 two-dimensional ultrasonic phased array, it is divided into 4 sub-arrays a, b, c, and d. Each sub-array includes 4×4 ultrasonic array elements, and at least one reference array element exists on each sub-array. For example, the reference array elements can be four ultrasonic array elements A, B, C, and D that are centrosymmetric.

[0052] In the optional embodiment, the two-dimensional ultrasonic phased array emits spherical waves corresponding to different virtual point sources each time, and the spherical wave emitted by a single virtual point source has a detection range as shown in Figure 4 All the virtual point sources have a preset positional relationship so that the echo data corresponding to all the virtual point sources can be focused on the imaging origin. Alternatively, the two-dimensional ultrasonic phased array emits four beams of spherical waves, and the center lines of the four beams correspond to the left front, right front, upper front, and lower front, respectively. The four beams of spherical waves can be focused on the same imaging origin, that is, the center lines of the four beams corresponding to the left front, right front, upper front, and lower front can intersect at a point.

[0053] In addition, each time the spherical wave transmission operation can include: The two-dimensional ultrasonic phased array emits spherical waves corresponding to different virtual point sources in sequence, and after each spherical wave transmission, all the ultrasonic elements simultaneously receive echo data to obtain a subset of echo data received by each subarray at each virtual point source. All the reference elements on the two-dimensional ultrasonic phased array emit spherical waves corresponding to the imaging origin, and all the reference elements simultaneously receive echo data to obtain a superimposed reference system. During each spherical wave transmission operation, not only a whole spherical wave transmission operation is performed, but also a detection operation based only on the reference elements is executed. For the detection operation of the reference elements, the received echo data is only used as a reference and is not used for actual microvessel imaging. Specifically, all the reference elements on the two-dimensional ultrasonic phased array emit spherical waves corresponding to the imaging origin, and all the reference elements simultaneously receive echo data. The echo data at this time is simply combined to obtain a superimposed reference system. The superimposed reference system is actually echo data with a wide range but low accuracy. On the basis of the superimposed reference system, the echo data of each subarray each time is filled in to obtain echo data with a wide range and high accuracy.

[0054] The subsets of echo data received by all the subarrays at each virtual point source are coherently superimposed based on the superimposed reference system to obtain ultrasonic image data. The coherent superimposition operation is performed under the reference of the superimposed reference system, thereby greatly reducing the calculation amount of the coherent superimposition.

[0055] For the above scheme, an example is shown as follows: As shown in Figure 3 All the elements on the two-dimensional ultrasonic phased array emit spherical waves corresponding to different virtual point sources in sequence, and after each spherical wave transmission, all the ultrasonic elements simultaneously receive echo data to obtain a subset of echo data received by each subarray at each virtual point source. Set a = {left front echo data; right front echo data; upper front echo data; lower front echo data} Set b = {left front echo data; right front echo data; upper front echo data; lower front echo data} Set c = {left front echo data; right front echo data; upper front echo data; lower front echo data} Set d = {left front echo data; right front echo data; upper front echo data; lower front echo data} All reference elements A, B, C, and D on the two-dimensional ultrasound phased array emit spherical waves corresponding to the imaging origin, and all reference elements simultaneously receive echo data to obtain a superposition reference system P; The sets a, b, c, and d are coherently superimposed based on the reference system P to obtain ultrasound image data.

[0056] As can be seen, the optional embodiment can use the superposition reference system obtained by the reference elements to assist the coherent superposition operation of the echo data in the process of coherent superposition of the echo data by designing the subarray and the reference elements on the subarray, thereby reducing the calculation amount of coherent superposition and improving the efficiency of coherent superposition.

[0057] In yet another optional embodiment, the operation of emitting a spherical wave by the two-dimensional ultrasound phased array each time can include: Each ultrasound element on the two-dimensional ultrasound phased array emits an ultrasound wave at a respective preset time point, so that the ultrasound wave emitted by the ultrasound phased array is equivalent to a spherical wave emitted from a virtual point source.

[0058] In the optional embodiment, the emission of the spherical wave can be realized by means of time delay emission. It is known that when a sound wave emitted from the same point reaches a certain plane, there will be a delay. By using this principle, as long as different arrays emit ultrasound waves at different time delays, the simulation of the spherical wave can be realized.

[0059] Optionally, a plurality of virtual point sources (spherical wave sources) are arranged behind the two-dimensional ultrasound array, each virtual point source can be regarded as a sound source, and a schematic diagram of a single virtual point source is shown in Figure 5 The time delay of the array elements can be used to control the emission of the spherical wave. The time delay of the i-th array element can be represented by the following formula

[0060]

[0061] wherein the coordinates of the virtual point source are , the coordinates of the i-th transducer array element are d represents the distance of the virtual point source transducer surface, is the distance from the current array element to the virtual point source, c is the sound speed in a specific medium, is the time delay of the i-th array element.

[0062] The spherical wave emitted by the two-dimensional ultrasonic phased array can be efficiently and simply realized by the above-mentioned delayed emission mode.

[0063] In yet another optional embodiment, the pixel points of each frame of the three-dimensional ultrasonic sequence image are , that is, corresponding to the spatial dimension, the time dimension corresponding to the ultrasonic sequence image is ; And the segmentation of the three-dimensional ultrasonic sequence image into a plurality of space-time sub-blocks can include: The segmentation of the three-dimensional ultrasonic sequence image into a plurality of space-time sub-blocks, the spatial dimension data corresponding to any space-time sub-block is , the time dimension data corresponding to any space-time sub-block is ; wherein , and the time dimension data and the spatial dimension data corresponding to adjacent two space-time sub-blocks have partial overlapping data.

[0064] In the embodiment of the application, the contrast agent is flowing, and in the time dimension of ultrasonic detection, the flowing contrast agent is still at almost the same position of the ultrasonic image. Therefore, the application adopts the operation of blocking, the contrast agent signal corresponding to the same part of the microvessel is only processed in one small block, and there is overlapping of the time dimension data and the spatial dimension data between the continuous two space-time sub-blocks, so that the internal relationship of the information is retained.

[0065] In yet another optional embodiment, the three-dimensional imaging operation of the microvessel according to the microbubble center point can include: Trajectory tracking is performed on the microbubble center point in each frame of the three-dimensional contrast agent image, and a plurality of three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image are obtained; Superimposing all the three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image obtains a three-dimensional distribution image of the microvessel.

[0066] In the optional embodiment, further optionally, the Kuhn-Munkres assignment algorithm can be used to pair the closest contrast signals of adjacent two frames, the algorithm takes the distance of each microbubble of adjacent two frames as the weight, pairs the microbubbles of adjacent two frames based on the idea of bipartite graph to make the total weight minimum, and finally removes the matching with too large distance and zero distance by setting a threshold, so as to realize the tracking of the three-dimensional space contrast signal.

[0067] In the optional embodiment, further optionally, the trajectory tracking can be performed on the microbubble center point in each frame of the three-dimensional contrast agent image, which can include: Identify a plurality of feature pixels in each frame of three-dimensional contrast agent image, and the feature pixel is a pixel point located at the contour edge of a microvessel; because the pixel point located at the contour edge is less and more recognizable, the pixel point at the contour edge can be selected to select the feature point more efficiently.

[0068] Obtain a preset number of adjacent pixel points around each feature pixel point, for each feature pixel point, a feature pattern is fitted according to the feature pixel point and the adjacent pixel points corresponding to the feature pixel point; the optional embodiment does not take a single pixel point as an object to find a pixel point in the next frame close to it as a matching point, but combines a plurality of pixel points around the feature pixel point to realize matching of the plurality of pixel points. Because the interval time of two adjacent frames of images is short, the combination of the plurality of pixel points has not been destroyed and deformed in the process of flowing with the contrast agent, therefore, matching the shape (which can be a three-dimensional shape or a two-dimensional shape obtained by sectioning from a certain angle) composed of the plurality of pixel points is more accurate than matching a single pixel point.

[0069] For each feature pattern in each frame of three-dimensional contrast agent image, a similar feature pattern corresponding to each feature pattern is determined in the adjacent frame of three-dimensional contrast image corresponding to the frame of three-dimensional contrast image; generally, in two frames of images within a short time interval, the feature pattern changes little with the flow of the contrast agent and can be easily identified.

[0070] According to the similar feature patterns corresponding to each feature pattern in all frames of three-dimensional contrast agent images, a trajectory corresponding to each feature point is determined.

[0071] It can be seen that the optional embodiment can realize more accurate microbubble center point trajectory tracking, and further realize more accurate three-dimensional imaging of microvessels.

[0072] Embodiment two The embodiment of the present application discloses a method for realizing four-dimensional anatomical structure and rapid three-dimensional myocardial microcirculation functional imaging in a heart cavity based on an interventional ultrasound catheter, and aims to provide an effective clinical diagnosis and postoperative monitoring scheme for structural heart disease diagnosis and cardiac electrophysiology surgery, and myocardial microcirculation related diseases, such as non-coronary obstructive coronary heart disease, heart transplantation and post-infarction recanalization evaluation.

[0073] Current clinical blood circulation imaging methods include MRA, DSA and Doppler ultrasound imaging, but are restricted by the physical diffraction limit and the amount of radiation allowed in clinical practice, and visualizing microcirculation remains a challenge. The ultrasound localization microscopy (ULM) technology fills this technical gap, but the existing ULM requires a sequence of multiple ultrasound images to reconstruct the microbubble center point trajectory, and superimposes all trajectories to obtain a microcirculation distribution map, which requires a long post-processing time. In addition, the heart is constantly beating, and collecting tens of thousands of high spatiotemporal coherence images requires a long acquisition time. In addition, the heart is surrounded by the sternum and has a large depth, so a compromise between imaging depth and imaging resolution is needed, and the frequency is generally lower, making it more difficult to capture the flow of contrast agent signals.

[0074] After that, the two-dimensional ultrasound image shows the cross-sectional structure of the tissue, and the blood flow of the whole tissue cannot be observed as a whole, because it has a high plane dependence. If the appropriate tissue cross section cannot be taken, there may be missed diagnosis in clinical application. In addition, due to the physiological movement of the organism, if the motion direction deviates from the imaging plane, the conventional motion correction algorithm is also difficult to correct, and additional artifacts will be introduced in the super-resolution image.

[0075] Based on the above technical defects of the prior art, the embodiment of the application innovatively proposes a myocardial microcirculation three-dimensional imaging method based on a two-dimensional micro ultrasound phased array. First, a two-dimensional micro ultrasound phased array is used in combination with a subarray beam synthesis technology to realize channel number and echo data compression, thereby realizing 4D ultrasound imaging. Then a sequence of three-dimensional myocardial ultrasound images containing microbubbles is collected, and then a three-dimensional weighted average microbubble positioning method innovatively proposed by the embodiment of the application can effectively shorten the post-processing time. In addition, compared with other microbubble center point positioning methods, the three-dimensional weighted positioning algorithm can reconstruct similar results using fewer frames of images, thereby greatly reducing the data acquisition time. Then the positioned microbubble center points are tracked between frames to obtain a plurality of microbubble motion trajectories, and finally all the microbubble trajectories are superimposed to obtain a three-dimensional myocardial microcirculation image.

[0076] The detailed disclosure of the technical scheme of the embodiment of the application is as follows: (1) Data acquisition The two-dimensional ultrasound phased array of the embodiment of the application divides all the elements into a plurality of (N) subarrays, decomposes the beam synthesis delay into coarse delay and fine delay, accurately calculates the fine delay within the subarray, combines a plurality of echo data into a group of data, and then uses the coarse delay to perform beam synthesis on the entire imaging area. In this way, the number of probe cables and the amount of beam synthesis data can be reduced by N times, greatly improving the imaging frame rate.

[0077] Although the imaging frame rate can be improved based on the aggregated line scanning, the imaging frame rate needs to be further improved due to the fast motion speed of the microbubbles in the vascular network. Embodiments of the present application utilize spatial spherical wave coherent compounding imaging, and a compromise between the imaging frame rate and the signal-to-noise ratio is achieved by emitting and receiving a plurality of groups of spherical waves and echo data and coherently superimposing the same. Specifically, a plurality of virtual point sources (spherical wave sources) can be arranged behind a two-dimensional ultrasonic array, each virtual point source can be regarded as a sound source, and the spherical wave emission can be controlled by setting the element delay. As shown in Figure 5 , the delay of the i th element can be represented by the following formula

[0078]

[0079] wherein the virtual point source coordinates are , the coordinates of the i th transducer element are , d represents the distance of the virtual point source transducer surface, is the distance from the current element to the virtual point source, c is the sound speed in a specific medium, is the delay of the i th element.

[0080] Due to the large amount of three-dimensional ultrasonic imaging echo data, the data transmission and storage capacity of the ultrasonic imaging system is limited, and therefore, 200 frames of coherent compounded echo data are collected for each group, and a total of 50 groups are collected.

[0081] As shown in Figure 6 , the embodiment of the present application uses a two-dimensional miniature ultrasonic phased array to detect myocardium.

[0082] (2) Three-dimensional singular value decomposition Due to the different spatiotemporal coherence of tissue and flowing microbubble signals, the tissue signal can be removed by using a wall filter algorithm, and the traditional singular value decomposition algorithm calculates the global singular value. The spatiotemporal coherence of large blood vessels is very low, and the microvascular signal is easily submerged.

[0083] Therefore, the three-dimensional block singular value decomposition wall filter algorithm of the embodiments of the present application can effectively extract the microvascular signal. The dimension of the image sequence is The entire time image sequence is divided into a plurality of sub-blocks with a size of , wherein , and there is an overlap between the sub-blocks. The three-dimensional matrix reconstruction is performed on the data of each sub-block, the first dimension is the spatial dimension, and the other dimension is the time dimension. The following formula is used to perform singular value decomposition on the two-dimensional matrix:

[0084] wherein is the two-dimensional decomposition matrix of the nth sub-block, where U and V are respectively matrices composed of spatial and temporal singular value vectors of is the singular value matrix, represents the conjugate transpose of the matrix. The high-order threshold and low-order threshold of the singular value truncation threshold and are determined according to the second derivative of the singular value curve. The point with the largest curvature change is considered to be the critical point between blood scattering and tissue scattering. After performing singular value decomposition on each sub-block, the microbubble signal of each pixel point in the image can be calculated :

[0085] where N is the total number of overlapping sub-blocks containing the target pixel , is the microbubble signal of the nth sub-block, is the corresponding singular value within the truncation threshold. The embodiments of the present invention can effectively reduce the influence of extremely low spatio-temporal coherence signals (such as physiological movements and large-diameter blood vessels) on microvascular signals, thereby improving microvascular imaging and detection rate.

[0086] (3) Microbubble center point localization Microbubble center point localization is the core of the imaging algorithm. The most commonly used methods in current research are the Gaussian model based on the point spread function and the localization method model based on radial symmetry. This requires a long time to collect multiple frames of image sequences and a long post-processing time, which greatly limits clinical applications.

[0087] The embodiments of the present invention propose a new three-dimensional microbubble center localization method, the three-dimensional weighted average center point localization method. Since the diameter of the microbubble is 1-3 microns, it can be regarded as an ideal scattering point in the imaging space, and its ultrasonic signal can be considered as the system point spread function, generally considered as a three-dimensional Gaussian model. First, a threshold is selected to perform binary processing on the microbubble signal image. Because multiple microbubble signals may overlap into a connected region, only one centroid point can be detected at this time, which may have a large positioning error. Here, morphological erosion and dilation are first performed on the microbubbles to separate the irregularly shaped connected regions, so that multiple microbubble signal centroid points can be detected. After binary processing and erosion dilation, the area of the region is calculated, and then the weighted average of the original image pixel values and the region area is calculated to obtain the weighted centroid of the microbubble center point. The reduced point set within the microbubble contour can be obtained as , and its centroid can be calculated by the following method:

[0088] where N is the number of points, is the normalized pixel value of.

[0089] (4) Microbubble center point tracking and particle velocity measurement After the center coordinates of each frame of microbubble signal are extracted, the Kuhn-Munkres assignment algorithm can be used to pair the nearest contrast signals of adjacent two frames. The algorithm takes the distance of each microbubble of adjacent two frames as a weight, pairs the microbubbles of adjacent two frames based on the idea of bipartite graph so that the total weight is minimized, and finally removes the matching with too large distance and zero distance by setting a threshold, so as to realize the tracking of three-dimensional space contrast signals. Further, the velocity of the i-th microbubble can be measured in turn as:

[0090] wherein is the reciprocal of the frame rate, is the velocity of the microbubble in the first frame. By the above method of the embodiment of the application, the flow rate of blood in the biological tissue can be obtained. This method has a relatively fast running speed, can realize the monitoring of blood dynamics, and the algorithm is simple and easy to implement.

[0091] Embodiment three The embodiment of the application discloses an ultrasonic imaging system, which can comprise: A two-dimensional ultrasonic phased array can comprise a plurality of ultrasonic array elements located on the same plane, and the two-dimensional ultrasonic phased array is used to: In a preset continuous time, the spherical wave transmission operation is performed multiple times, each time the spherical wave transmission operation can comprise: the two-dimensional ultrasonic phased array successively emits spherical waves, after each spherical wave transmission, all ultrasonic array elements simultaneously receive echo data, and after the coherent superposition of all echo data, ultrasonic image data is obtained, and the ultrasonic image data can at least comprise contrast agent echoes; A host computer is in communication connection with the two-dimensional ultrasonic phased array, and is used to: According to the ultrasonic image data obtained by each spherical wave transmission operation, a three-dimensional ultrasonic sequence image is obtained; The three-dimensional ultrasonic sequence image is divided into a plurality of space-time sub-blocks, each space-time sub-block can comprise part of the time dimension data and part of the spatial dimension data of the three-dimensional ultrasonic sequence image, and the time dimension data and the spatial dimension data corresponding to adjacent two space-time sub-blocks have part of the overlapping data; The singular value decomposition is performed on all space-time sub-blocks, the contrast agent signal is extracted, and the three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasonic sequence image is obtained according to the contrast agent signal; The three-dimensional contrast agent sequence image is subjected to binaryzation processing to obtain a plurality of connected domains, and the microbubble center point corresponding to each connected domain is calculated; The microbubble center point is used to perform a microvessel three-dimensional imaging operation.

[0092] The host computer can also be used to implement other steps disclosed in Embodiment One and Embodiment Two of the present application to achieve the final three-dimensional imaging of microvessels.

[0093] Embodiment Four The embodiment of the present application discloses a microvessel three-dimensional imaging device based on an ultrasonic phased array, which can be connected with a two-dimensional ultrasonic phased array, and the two-dimensional ultrasonic phased array can include a plurality of ultrasonic array elements located in the same plane. The device can include: The transmission module is configured to control the execution of the spherical wave transmission operation multiple times within a preset continuous time. Each spherical wave transmission operation can include: controlling the two-dimensional ultrasonic phased array to sequentially emit spherical waves, receiving echo data simultaneously by all ultrasonic array elements after each spherical wave transmission, obtaining ultrasonic image data by coherently superimposing all echo data, and the ultrasonic image data can include at least contrast agent echo. The signal receiving and collecting module is configured to obtain three-dimensional ultrasonic sequence images from the ultrasonic image data obtained by each spherical wave transmission operation. The data segmentation module is configured to segment the three-dimensional ultrasonic sequence images into a plurality of spatio-temporal sub-blocks, each spatio-temporal sub-block can include partial time dimension data and partial space dimension data of the three-dimensional ultrasonic sequence images, and the time dimension data and the space dimension data corresponding to adjacent two spatio-temporal sub-blocks have partial overlapping data. The singular value decomposition module is configured to perform singular value decomposition on all spatio-temporal sub-blocks, extract contrast agent signals, and obtain three-dimensional contrast agent sequence images corresponding to the three-dimensional ultrasonic sequence images according to the contrast agent signals. The center point positioning module is configured to perform binaryzation processing on the three-dimensional contrast agent sequence images to obtain a plurality of connected domains, and calculate microbubble center points corresponding to each connected domain. The imaging module is configured to perform microvessel three-dimensional imaging operation according to the microbubble center points.

[0094] In an optional embodiment, the two-dimensional ultrasonic phased array can include a plurality of sub-arrays located in the same plane, and each sub-array can include a plurality of ultrasonic array elements located in the same plane, wherein at least one ultrasonic array element in each sub-array is determined as a reference array element. Each spherical wave emitted by the two-dimensional ultrasonic phased array corresponds to a different virtual point source, and all virtual point sources have a preset positional relationship so that the echo data corresponding to all virtual point sources can be focused on the imaging origin. Each spherical wave transmission operation can include: controlling the two-dimensional ultrasonic phased array to sequentially emit spherical waves corresponding to different virtual point sources, receiving echo data simultaneously by all ultrasonic array elements after each spherical wave transmission, and obtaining echo subsets received by each sub-array at each virtual point source. All reference elements on the two-dimensional ultrasonic phased array emit spherical waves corresponding to the imaging origin, all reference elements simultaneously receive echo data to obtain a superimposed reference system; After the coherent superposition of all echo subsets received by all sub-arrays at each virtual point source based on the superimposed reference system, the ultrasonic image data is obtained.

[0095] In another optional embodiment, the operation of the two-dimensional ultrasonic phased array emitting a spherical wave each time can include: Each ultrasonic element on the two-dimensional ultrasonic phased array emits an ultrasonic wave at a respective preset time point, so that the ultrasonic wave emitted by the ultrasonic phased array is equivalent to a spherical wave emitted from a virtual point source.

[0096] In yet another optional embodiment, the pixel points of each frame of image in the three-dimensional ultrasonic sequence image are , and the time dimension corresponding to the ultrasonic sequence image is ; In addition, the specific operation mode of the data segmentation module for segmenting the three-dimensional ultrasonic sequence image into multiple spatio-temporal sub-blocks can include: The three-dimensional ultrasonic sequence image is segmented into multiple spatio-temporal sub-blocks, and the spatial dimension data corresponding to any spatio-temporal sub-block is , and the time dimension data corresponding to any spatio-temporal sub-block is ; wherein , and the time dimension data and the spatial dimension data corresponding to adjacent two spatio-temporal sub-blocks have partial overlapping data.

[0097] In yet another optional embodiment, the imaging module can perform three-dimensional imaging of the microvessel according to the microbubble center point, which can include: Trajectory tracking is performed on the microbubble center point in each frame of three-dimensional contrast agent image to obtain multiple three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image; All three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image are superimposed to obtain a three-dimensional distribution image of the microvessel.

[0098] In yet another optional embodiment, the specific operation mode of the imaging module for performing trajectory tracking on the microbubble center point in each frame of three-dimensional contrast agent image can include: Identify multiple feature pixels in each frame of three-dimensional contrast agent image, and the feature pixel is a pixel point located at the edge of the microvessel contour; A preset number of adjacent pixels around each feature pixel are obtained, and for each feature pixel, a feature pattern is fitted according to the feature pixel and the adjacent pixels corresponding to the feature pixel; For each feature pattern in each frame three-dimensional contrast image, a similar feature pattern corresponding to each feature pattern in the adjacent frame three-dimensional contrast image corresponding to the frame three-dimensional contrast image is determined; According to the similar feature pattern corresponding to each feature pattern in all frame three-dimensional contrast images, a trajectory corresponding to each feature point is determined.

[0099] Embodiment five Please refer to Figure 7 , Figure 7 is a structural schematic diagram of a microvessel three-dimensional imaging system based on an ultrasonic phased array according to an embodiment of the present application. As shown in Figure 7 , the microvessel three-dimensional imaging system based on the ultrasonic phased array can include: a memory 201 storing executable program codes; a processor 202 coupled with the memory 201; The processor 202 invokes the executable program codes stored in the memory 201 to execute the steps in the microvessel three-dimensional imaging method based on the ultrasonic phased array described in the embodiment one or the embodiment two of the present application.

[0100] Embodiment six The embodiment of the present application discloses a computer storage medium storing computer instructions, which, when invoked, is used to execute the steps in the microvessel three-dimensional imaging method based on the ultrasonic phased array described in the embodiment one or the embodiment two of the present application.

[0101] The above-described device embodiments are only schematic, wherein the modules illustrated as separate components can or can not be physically separate, and the components illustrated as modules can or can not be physical modules, i.e., can be located in one place, or can be distributed on multiple network modules. Part or all of the modules can be selected according to actual needs to achieve the purpose of the present embodiment scheme. Those skilled in the art can understand and implement without creative labor.

[0102] Those skilled in the art can clearly understand the implementation of the various embodiments by means of software and the necessary general hardware platform through the specific description of the above embodiments, and of course, the various embodiments can also be implemented by hardware. Based on such understanding, the above technical solutions, essentially or in other words, the part of the prior art that makes a contribution, can be embodied in the form of a software product, and the computer software product can be stored in a computer readable storage medium, including a read-only memory (ROM), a random access memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a one-time programmable read-only memory (OTPROM), an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disk storage, a magnetic disk storage, a magnetic tape storage, or any other computer readable medium that can be used to carry or store data.

[0103] Finally, it should be noted that: the ultrasonic phased array-based microvessel three-dimensional imaging method and system disclosed by the medium disclosed by the embodiments of the present application are only the preferred embodiments of the present application, and are used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that; the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalents; and these modifications 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.

Claims

1. A method for three-dimensional imaging of microvessels based on an ultrasonic phased array, characterized in that, The two-dimensional ultrasonic phased array includes a plurality of ultrasonic array elements in the same plane, and the method comprises: In a preset continuous time, a spherical wave emission operation is performed multiple times, each time the spherical wave emission operation comprising: the two-dimensional ultrasonic phased array sequentially emits spherical waves, after each spherical wave emission, all ultrasonic array elements simultaneously receive echo data, and after coherent superposition of all echo data, ultrasonic image data is obtained, the ultrasonic image data at least including contrast agent echoes; According to the ultrasonic image data obtained in each spherical wave emission operation, a three-dimensional ultrasonic sequence image is obtained; The three-dimensional ultrasonic sequence image is divided into a plurality of space-time sub-blocks, each space-time sub-block including partial time dimension data and partial space dimension data of the three-dimensional ultrasonic sequence image, and adjacent two space-time sub-blocks have partially overlapping time dimension data and space dimension data; Singular value decomposition is performed on all space-time sub-blocks to extract contrast agent signals, and a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasonic sequence image is obtained according to the contrast agent signals; The three-dimensional contrast agent sequence image is binarized to obtain a plurality of connected domains, and a microbubble center point corresponding to each connected domain is calculated according to each connected domain; Microvessel three-dimensional imaging operation is performed according to the microbubble center point.

2. The ultrasonic phased-array based microvessel three-dimensional imaging method of claim 1, wherein, The two-dimensional ultrasonic phased array includes a plurality of sub-arrays in the same plane, each sub-array including a plurality of ultrasonic array elements in the same plane, wherein at least one ultrasonic array element in each sub-array is determined as a reference array element; Each spherical wave emitted by the two-dimensional ultrasonic phased array corresponds to a different virtual point source, and all virtual point sources have a preset positional relationship, so that echo data corresponding to all virtual point sources can be focused on an imaging origin point; Each spherical wave emission operation comprises: The two-dimensional ultrasonic phased array sequentially emits spherical waves corresponding to different virtual point sources, after each spherical wave emission, all ultrasonic array elements simultaneously receive echo data, and a subset of echoes received by each sub-array at each virtual point source is obtained; All reference array elements in the two-dimensional ultrasonic phased array emit spherical waves corresponding to the imaging origin point, and all reference array elements simultaneously receive echo data to obtain a superposition reference system; After coherent superposition of the subset of echoes received by all sub-arrays at each virtual point source based on the superposition reference system, ultrasonic image data is obtained.

3. The method of claim 1 or 2, wherein the method further comprises: Each spherical wave emission operation by the two-dimensional ultrasonic phased array comprises: Each ultrasonic array element in the two-dimensional ultrasonic phased array emits ultrasonic waves at a respective preset time point, so that the ultrasonic waves emitted by the two-dimensional ultrasonic phased array are equivalent to spherical waves emitted from a virtual point source.

4. The ultrasonic phased-array based microvessel three-dimensional imaging method of claim 1, wherein, The pixel points of each frame image in the three-dimensional ultrasound sequence image are , and the time dimension corresponding to the three-dimensional ultrasound sequence image is ; The division of the three-dimensional ultrasonic sequence image into a plurality of space-time sub-blocks comprises: The three-dimensional ultrasound sequence image is divided into a plurality of spatio-temporal sub-blocks, and the spatial dimension data corresponding to any one spatio-temporal sub-block is , the time dimension data corresponding to any one spatio-temporal sub-block is ; wherein , and the time dimension data and the spatial dimension data corresponding to adjacent two spatio-temporal sub-blocks exist partial overlapping data.

5. The method according to any one of claims 1-2, 4, wherein, The microvessel three-dimensional imaging operation according to the microbubble center point comprises: Trajectory tracking is performed on the microbubble center points in each three-dimensional contrast agent image to obtain a plurality of three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image; All three-dimensional microbubble trajectories corresponding to the three-dimensional contrast agent sequence image are superimposed to obtain a three-dimensional microvessel distribution image.

6. The method of claim 5, wherein the method is performed by a system comprising: a microvascular imaging probe comprising a plurality of ultrasound transducers; a controller configured to control the plurality of ultrasound transducers; and a processor configured to receive the plurality of ultrasound signals from the plurality of ultrasound transducers and to generate the three-dimensional microvascular image. Trajectory tracking is performed on the microbubble center points in each frame of three-dimensional contrast agent image, including: Identifying a plurality of feature pixel points in each frame of three-dimensional contrast agent image, the feature pixel points being pixel points located at the edge of the microvessel profile; Obtaining a preset number of adjacent pixel points around each feature pixel point, and for each feature pixel point, fitting a feature pattern according to the feature pixel point and the adjacent pixel points corresponding to the feature pixel point; For each feature pattern in each frame of three-dimensional contrast agent image, a similar feature pattern corresponding to each feature pattern is determined in the adjacent frame of three-dimensional contrast image corresponding to the frame of three-dimensional contrast image; According to the similar feature patterns corresponding to each feature pattern in all frames of three-dimensional contrast agent image, the trajectory corresponding to each feature point is determined.

7. An ultrasonic phased array based microvessel three-dimensional imaging apparatus, characterized by, The two-dimensional ultrasonic phased array includes a plurality of ultrasonic array elements located in the same plane, and the device includes: A transmission module configured to control the execution of a spherical wave transmission operation multiple times within a preset continuous time; Wherein, each time the spherical wave transmission operation includes: controlling the two-dimensional ultrasonic phased array to sequentially emit spherical waves, receiving echo data simultaneously by all ultrasonic array elements after each spherical wave transmission, and obtaining ultrasonic image data by coherently superimposing all echo data, the ultrasonic image data including at least contrast agent echoes; A signal receiving and collecting module configured to obtain three-dimensional ultrasonic sequence images from the ultrasonic image data obtained by each spherical wave transmission operation; A data segmentation module configured to segment the three-dimensional ultrasonic sequence images into a plurality of spatio-temporal sub-blocks, each spatio-temporal sub-block including partial time dimension data and partial space dimension data of the three-dimensional ultrasonic sequence images, and adjacent two spatio-temporal sub-blocks having partially overlapping time dimension data and space dimension data; A singular value decomposition module configured to perform singular value decomposition on all spatio-temporal sub-blocks, extract contrast agent signals, and obtain three-dimensional contrast agent sequence images corresponding to the three-dimensional ultrasonic sequence images according to the contrast agent signals; A center point positioning module configured to perform binaryzation processing on the three-dimensional contrast agent sequence images to obtain a plurality of connected domains, and calculate microbubble center points corresponding to each connected domain according to the connected domain; An imaging module configured to perform microvessel three-dimensional imaging operation according to the microbubble center points.

8. An ultrasound imaging system, characterized by The ultrasonic imaging system includes: A two-dimensional ultrasonic phased array including a plurality of ultrasonic array elements located in the same plane, the two-dimensional ultrasonic phased array being configured to: Execute a spherical wave transmission operation multiple times within a preset continuous time, each time the spherical wave transmission operation including: the two-dimensional ultrasonic phased array sequentially emitting spherical waves, receiving echo data simultaneously by all ultrasonic array elements after each spherical wave transmission, and obtaining ultrasonic image data by coherently superimposing all echo data, the ultrasonic image data including at least contrast agent echoes; A host computer, the host computer being in communication connection with the two-dimensional ultrasonic phased array and being configured to: Obtain three-dimensional ultrasonic sequence images from the ultrasonic image data obtained by each spherical wave transmission operation; The three-dimensional ultrasound sequence image is divided into a plurality of spatio-temporal sub-blocks, each spatio-temporal sub-block including partial time dimension data and partial space dimension data of the three-dimensional ultrasound sequence image, and adjacent two spatio-temporal sub-blocks corresponding to time dimension data and space dimension data having partial overlapping data; singular value decomposition is performed on all the spatio-temporal sub-blocks to extract contrast agent signals, and a three-dimensional contrast agent sequence image corresponding to the three-dimensional ultrasound sequence image is obtained according to the contrast agent signals; the three-dimensional contrast agent sequence image is subjected to binaryzation processing to obtain a plurality of connected domains, and a microbubble center point corresponding to each connected domain is calculated according to the connected domain; a microvessel three-dimensional imaging operation is performed according to the microbubble center point.

9. An ultrasonic phased array based microvessel three-dimensional imaging system, characterized by, The system comprises a memory storing executable program codes, a processor coupled with the memory, and the processor invokes the executable program codes stored in the memory to execute the microvessel three-dimensional imaging method based on an ultrasound phased array as claimed in any one of claims 1-7.

10. A computer storage medium, characterized in that, The computer storage medium stores computer instructions, and the computer instructions are invoked to execute the microvessel three-dimensional imaging method based on an ultrasound phased array as claimed in any one of claims 1-7.

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