Microvessel imaging method and system based on ultrasonic phased array, medium

Abstract

The application discloses a kind of microvessel imaging method and system based on ultrasonic phased array, medium, it is related to ultrasonic imaging technology.The present application can obtain ultrasonic sequence image, the ultrasonic sequence image is segmented into multiple space-time sub-blocks, singular value decomposition is carried out to all space-time sub-blocks, extract contrast agent signal, contrast agent sequence image is mapped to Hough space, center point positioning is carried out to contrast agent signal based on Hough transform, generate all microbubble center points, finally carry out microvessel imaging operation.Wherein, the ultrasonic sequence image is segmented into multiple space-time sub-blocks, after blocking, the adverse effects of large blood vessels and physiological movement on data can be reduced, adjacent space-time sub-blocks exist overlapping data, then the continuity of blood flow can be reflected;The positioning algorithm based on Hough transform has the advantages of less required data amount, fast processing speed and the like, so as to reduce the data amount dependence in the process of microvessel imaging, improve imaging efficiency.

Description

Technical Field

[0001] This invention relates to the field of ultrasound imaging technology, and in particular to a microvascular imaging method, system, and medium based on ultrasound phased array. Background Technology

[0002] Currently, commonly used medical imaging techniques for examining the circulatory system in clinical practice include computed tomography (CT), magnetic resonance angiography (MRA), digital subtraction angiography (DSA), and contrast-enhanced ultrasound (CEUS). However, none of these techniques can visualize the microcirculatory system at the micrometer level.

[0003] In 2015, French researchers proposed a novel ultrasound imaging method called ultrasound-guided microscopy, also known as ultrasound super-resolution microvascular imaging (SR). This method involves intravenously injecting an ultrasound contrast agent and using an ultrafast ultrasound imaging algorithm to track the flow trajectory of the contrast agent. By superimposing multiple frames of the contrast agent trajectory, the microvascular morphology can be reconstructed and hemodynamic parameters can be calculated. The core of this method is the localization of the contrast agent's center point. In recent years, researchers both domestically and internationally have developed several localization methods, including those based on the Gaussian model of the ultrasound point spread function and the deconvolution method of the contrast agent signal, and the radial symmetry localization method using the contrast agent signal. These methods have been successfully applied to microvascular localization in the brain, liver, kidneys, and tumor tissues. However, these methods rely on tens or even hundreds of thousands of image sequences, requiring long acquisition and post-processing times, which greatly limits the clinical application of SR.

[0004] In 2024, Professor Tang's team at Imperial College London used phased array ultrafast ultrasound imaging combined with electrophysiological equipment to acquire transthoracic echocardiogram sequences to visualize myocardial microcirculation and coronary arteries. However, this method requires a long acquisition time and has low imaging efficiency.

[0005] Therefore, it is necessary to propose a new microvascular imaging method based on ultrasound phased array to reduce the data volume dependence in the microvascular imaging process, thereby improving imaging efficiency. Summary of the Invention

[0006] This invention provides a microvascular imaging method, system, and medium based on ultrasound phased array, which reduces the data volume dependence in the microvascular imaging process, thereby improving imaging efficiency.

[0007] To address the aforementioned technical problems, the first aspect of this invention discloses a microvascular imaging method based on an ultrasound phased array, wherein the ultrasound phased array comprises multiple ultrasound array elements arranged in a straight line, and the method includes:

[0008] Acquire ultrasound sequence images, wherein the ultrasound sequence images are a series of microvascular ultrasound image data acquired by an ultrasound phased array at a preset position and within a preset continuous time, and the ultrasound image data includes at least contrast agent echoes;

[0009] The ultrasound sequence image is divided into multiple spatiotemporal sub-blocks. Each spatiotemporal sub-block includes part of the time dimension data and part of the spatial dimension data of the ultrasound sequence image. Furthermore, there is partial overlap between the time dimension data and spatial dimension data of two adjacent spatiotemporal sub-blocks.

[0010] Singular value decomposition is performed on all the spatiotemporal sub-blocks to extract the contrast agent signal, and the contrast agent sequence image corresponding to the ultrasound sequence image is obtained based on the contrast agent signal.

[0011] The contrast agent sequence image is mapped to Hough space, and the center point of the contrast agent signal is located based on the Hough transform to generate the center point of all microbubbles.

[0012] Microvascular imaging is performed based on the center point of the microbubble.

[0013] As an optional implementation, in the first aspect of the present invention, the ultrasound phased array acquires a series of microvascular ultrasound image data at a preset position and within a preset continuous time period, including:

[0014] Within a preset continuous time period, spherical wave emission operations are performed multiple times. Each spherical wave emission operation includes: the ultrasonic phased array sequentially emits virtual spherical waves, and after each virtual spherical wave emission, all ultrasonic array elements simultaneously receive scattered echo signals. All scattered echo signals are coherently superimposed to obtain ultrasonic image data.

[0015] Based on the ultrasound image data obtained from each spherical wave emission operation, a series of microvascular ultrasound image data are obtained;

[0016] In this system, each virtual spherical wave emitted by the ultrasonic phased array corresponds to a different virtual point source, and all virtual point sources have a preset positional relationship so that different virtual spherical waves can detect different directions.

[0017] As an optional implementation, in the first aspect of the present invention, the virtual point source includes a first-order virtual point source and a second-order virtual point source, wherein all the first-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all the first-order virtual point sources can be focused on the imaging origin; all the second-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all the second-order virtual point sources can also be focused on the imaging origin; and the distance from the first-order virtual point source to the ultrasonic phased array is less than the distance from the second-order virtual point source to the ultrasonic phased array.

[0018] And, each of the spherical wave emission operations includes:

[0019] The ultrasonic phased array sequentially emits virtual spherical waves corresponding to the first-order virtual point source. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. The superimposed reference frame is obtained by coherently superimposing all the scattered echo signals.

[0020] The ultrasonic phased array sequentially emits virtual spherical waves corresponding to the second-order virtual point sources. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. After adding all the scattered echo signals to the superimposed reference frame, ultrasonic image data is obtained.

[0021] As an optional implementation, in the first aspect of the invention, the operation of the ultrasonic phased array emitting virtual spherical waves each time includes:

[0022] Each of the linearly arranged ultrasonic array elements emits ultrasonic waves at its own preset time point, so that the ultrasonic waves emitted by the ultrasonic phased array are equivalent to spherical waves emitted from a virtual point source.

[0023] As an optional implementation, in the first aspect of the invention, the number of pixels in each frame of the ultrasound sequence image is 100. The time dimension corresponding to the ultrasound sequence images is ;

[0024] And, the step of segmenting the ultrasound sequence image into multiple spatiotemporal sub-blocks includes:

[0025] The ultrasound sequence image is segmented into multiple spatiotemporal sub-blocks, and the spatial dimension data corresponding to any one spatiotemporal sub-block is: The time dimension data corresponding to any spatiotemporal sub-block is ;in , , Furthermore, there is some overlap between the time dimension data and the spatial dimension data of two adjacent spatiotemporal sub-blocks.

[0026] As an optional implementation, in the first aspect of the invention, mapping the contrast agent sequence image to Hough space, locating the center point of the contrast agent signal based on the Hough transform, and generating the center points of all microbubbles includes:

[0027] The contrast agent sequence images are mapped to Hough space so that points on the same curve in each frame of the contrast agent image correspond to a series of intersecting surfaces in Hough space.

[0028] Output the set of contour points corresponding to the same microbubble signal in each frame of contrast agent image based on the surfaces intersecting the same curve in Hough space;

[0029] For each microbubble signal in each frame of the contrast agent image, the center point of the microbubble corresponding to that microbubble signal is calculated according to the following formula. :

[0030]

[0031]

[0032] Where N is the number of contour points in the contour point set corresponding to the microbubble signal. This refers to the i-th contour point within the contour point set corresponding to the microbubble signal. For the i-th contour point The corresponding normalized pixel value.

[0033] As an optional implementation, in the first aspect of the present invention, the microvascular imaging operation based on the microbubble center point includes:

[0034] Trajectory tracking is performed on the center point of microbubbles in each frame of contrast agent image to obtain multiple microbubble trajectories corresponding to the contrast agent sequence image;

[0035] The microvessel distribution image is obtained by superimposing all the microbubble trajectories corresponding to the contrast agent sequence image.

[0036] A second aspect of this invention discloses a microvascular imaging device based on an ultrasound phased array, wherein the ultrasound phased array comprises a plurality of linearly arranged ultrasound array elements, and the device includes:

[0037] The data acquisition module is used to acquire ultrasound sequence images, wherein the ultrasound sequence images are a series of microvascular ultrasound image data acquired by an ultrasound phased array at a preset position and within a preset continuous time, and the ultrasound image data includes at least contrast agent echoes.

[0038] The data segmentation module is used to segment the ultrasound sequence image into multiple spatiotemporal sub-blocks. Each spatiotemporal sub-block includes part of the time dimension data and part of the spatial dimension data of the ultrasound sequence image, and there is partial overlap between the time dimension data and spatial dimension data of two adjacent spatiotemporal sub-blocks.

[0039] The data decomposition module is used to perform singular value decomposition on all the spatiotemporal sub-blocks, extract the contrast agent signal, and obtain the contrast agent sequence image corresponding to the ultrasound sequence image based on the contrast agent signal.

[0040] The center point localization module is used to map the contrast agent sequence image to the Hough space, locate the center point of the contrast agent signal based on the Hough transform, and generate the center point of all microbubbles.

[0041] An imaging module is used to perform microvascular imaging based on the center point of the microbubble.

[0042] As an optional implementation, in a second aspect of the invention, the ultrasound phased array acquires a series of microvascular ultrasound image data at a preset position and within a preset continuous time period, including:

[0043] Within a preset continuous time period, spherical wave emission operations are performed multiple times. Each spherical wave emission operation includes: the ultrasonic phased array sequentially emits virtual spherical waves, and after each virtual spherical wave emission, all ultrasonic array elements simultaneously receive scattered echo signals. All scattered echo signals are coherently superimposed to obtain ultrasonic image data.

[0044] Based on the ultrasound image data obtained from each spherical wave emission operation, a series of microvascular ultrasound image data are obtained;

[0045] In this system, each virtual spherical wave emitted by the ultrasonic phased array corresponds to a different virtual point source, and all virtual point sources have a preset positional relationship so that different virtual spherical waves can detect different directions.

[0046] As an optional implementation, in a second aspect of the present invention, the virtual point source includes a first-order virtual point source and a second-order virtual point source, wherein all the first-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all the first-order virtual point sources can be focused on the imaging origin; all the second-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all the second-order virtual point sources can also be focused on the imaging origin; and the distance from the first-order virtual point source to the ultrasonic phased array is less than the distance from the second-order virtual point source to the ultrasonic phased array.

[0047] As an optional implementation, in the second aspect of the present invention, the arrangement of virtual point sources can also be set as linear or circular, etc.

[0048] And, each of the spherical wave emission operations includes:

[0049] The ultrasonic phased array sequentially emits virtual spherical waves corresponding to the first-order virtual point source. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. The superimposed reference frame is obtained by coherently superimposing all the scattered echo signals.

[0050] The ultrasonic phased array sequentially emits virtual spherical waves corresponding to the second-order virtual point sources. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. After adding all the scattered echo signals to the superimposed reference frame, ultrasonic image data is obtained.

[0051] As an optional implementation, in a second aspect of the invention, the operation of the ultrasonic phased array emitting virtual spherical waves each time includes:

[0052] Each of the linearly arranged ultrasonic array elements emits ultrasonic waves at its own preset time point, so that the ultrasonic waves emitted by the ultrasonic phased array are equivalent to spherical waves emitted from a virtual point source.

[0053] As an optional implementation, in a second aspect of the invention, the number of pixels in each frame of the ultrasound sequence image is... The time dimension corresponding to the ultrasound sequence images is ;

[0054] Furthermore, the specific operation method by which the data segmentation module segments the ultrasound sequence image into multiple spatiotemporal sub-blocks includes:

[0055] The ultrasound sequence image is segmented into multiple spatiotemporal sub-blocks, and the spatial dimension data corresponding to any one spatiotemporal sub-block is: The time dimension data corresponding to any spatiotemporal sub-block is ;in , , Furthermore, there is some overlap between the time dimension data and the spatial dimension data of two adjacent spatiotemporal sub-blocks.

[0056] As an optional implementation, in a second aspect of the invention, the specific operation method of the center point localization module mapping the contrast agent sequence image to Hough space, performing center point localization of the contrast agent signal based on Hough transform, and generating all microbubble center points includes:

[0057] The contrast agent sequence images are mapped to Hough space so that points on the same curve in each frame of the contrast agent image correspond to a series of intersecting surfaces in Hough space.

[0058] Output the set of contour points corresponding to the same microbubble signal in each frame of contrast agent image based on the surfaces intersecting the same curve in Hough space;

[0059] For each microbubble signal in each frame of the contrast agent image, the center point of the microbubble corresponding to that microbubble signal is calculated according to the following formula. :

[0060]

[0061]

[0062] Where N is the number of contour points in the contour point set corresponding to the microbubble signal. This refers to the i-th contour point within the contour point set corresponding to the microbubble signal. For the i-th contour point The corresponding normalized pixel value.

[0063] As an optional implementation, in a second aspect of the invention, the imaging module performs microvascular imaging based on the microbubble center point, including:

[0064] Trajectory tracking is performed on the center point of microbubbles in each frame of contrast agent image to obtain multiple microbubble trajectories corresponding to the contrast agent sequence image;

[0065] The microvessel distribution image is obtained by superimposing all the microbubble trajectories corresponding to the contrast agent sequence image.

[0066] A third aspect of this invention discloses a microvascular imaging system based on an ultrasound phased array, the system comprising:

[0067] Memory containing executable program code;

[0068] A processor coupled to the memory;

[0069] The processor calls the executable program code stored in the memory to execute the microvascular imaging method based on ultrasound phased array disclosed in the first aspect of the present invention.

[0070] The fourth aspect of the present invention discloses a computer storage medium storing computer instructions, which, when invoked, are used to execute the microvascular imaging method based on ultrasound phased array disclosed in the first aspect of the present invention.

[0071] Compared with existing technologies, the microvascular imaging method based on ultrasound phased array of the present invention can acquire ultrasound sequence images, segment the ultrasound sequence images into multiple spatiotemporal sub-blocks, perform singular value decomposition on all spatiotemporal sub-blocks to extract contrast agent signals, map the contrast agent sequence images to Hough space, locate the center points of the contrast agent signals based on Hough transform, generate the center points of all microbubbles, and finally perform microvascular imaging operations. Segmenting the ultrasound sequence images into multiple spatiotemporal sub-blocks reduces the adverse effects of large blood vessels and physiological movements on the data. The overlapping data in adjacent spatiotemporal sub-blocks reflects the continuity of blood flow. The localization algorithm based on Hough transform has advantages such as requiring less data and having a faster processing speed, thereby reducing the data volume dependence in the microvascular imaging process and improving imaging efficiency. Attached Figure Description

[0072] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0073] Figure 1 This is a schematic flowchart of a microvascular imaging method based on ultrasound phased array disclosed in an embodiment of the present invention;

[0074] Figure 2 This is a schematic diagram of the process of processing the ultrasound sequence image through singular value decomposition and center point localization as disclosed in the embodiments of the present invention;

[0075] Figure 3 This is a schematic diagram illustrating the different imaging ranges of point sources at different distances from the ultrasonic phased array, as disclosed in an embodiment of the present invention.

[0076] Figure 4 This is a schematic diagram of the virtual spherical wave detection range corresponding to the first-order point source and the second-order point source disclosed in the embodiments of the present invention;

[0077] Figure 5 This is a schematic diagram of the spherical wave emission situation corresponding to multiple virtual point sources disclosed in the embodiments of the present invention;

[0078] Figure 6 This is a spatial relationship diagram between a single point source and an ultrasonic phased array disclosed in an embodiment of the present invention;

[0079] Figure 7 This is a schematic diagram of using a miniature phased array to detect myocardium, as disclosed in an embodiment of the present invention;

[0080] Figure 8 This is a schematic diagram of the structure of a microvascular imaging system based on an ultrasound phased array disclosed in an embodiment of the present invention. Detailed Implementation

[0081] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0082] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product, or end that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or ends.

[0083] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0084] Example 1

[0085] Please see Figure 1 , Figure 1 This is a schematic flowchart of a microvascular imaging method based on ultrasound phased array disclosed in an embodiment of the present invention. Wherein, Figure 1 The described ultrasound phased array-based microvascular imaging method can be integrated into an imaging device, which can be integrated into a cloud server or a local server. Figure 1 The described microvascular imaging method based on ultrasound phased array can also be integrated into a host computer that communicates with the ultrasound phased array. For example... Figure 1 As shown, this ultrasound phased array-based microvascular imaging method may include the following operations:

[0086] Step 101: Obtain ultrasound sequence images.

[0087] In this embodiment of the invention, the ultrasound sequence image is a series of microvascular ultrasound image data acquired by an ultrasound phased array at a preset location within a preset continuous time period. The ultrasound image data may include at least contrast agent echoes. The ultrasound sequence image consists of multiple ultrasound images in consecutive frames, which include the contrast agent echo situation within the microvessels within the preset continuous time period.

[0088] The ultrasonic phased array can include multiple ultrasonic elements arranged in a straight line. When emitting ultrasonic waves, if all ultrasonic elements in the phased array emit ultrasonic waves simultaneously, the ultrasonic wave emitted by the entire phased array is a two-dimensional plane wave, with its wavefront spreading in a planar manner. If each ultrasonic element in the phased array emits ultrasonic waves at different preset times, different types of ultrasonic waves can be emitted, such as two-dimensional plane waves propagating at a certain angle, or two-dimensional spherical waves with a point source. In this embodiment of the invention, each ultrasonic element in the phased array can be selectively controlled to emit ultrasonic waves at different preset times, thereby emitting a two-dimensional spherical wave with a point source. Spherical waves have the advantage of a wide detection range.

[0089] Step 102: Divide the ultrasound sequence image into multiple spatiotemporal sub-blocks.

[0090] In this embodiment of the invention, since the spatiotemporal coherence of tissue and contrast agent signals is different, tissue corresponds to a high spatiotemporal coherence signal in the image sequence, while contrast agent signal corresponds to a low spatiotemporal coherence signal, so singular value decomposition can be used to separate them.

[0091] In ultrasound imaging, tissues and flowing contrast agents (such as microbubbles) exhibit different spatiotemporal properties in image sequences:

[0092] Organization: Due to its relatively stable structure, it changes little between consecutive image frames, exhibiting high spatiotemporal coherence (strong correlation in time and space).

[0093] Contrast agent: As blood flows rapidly, its position and intensity change dramatically over time, exhibiting low spatiotemporal coherence (weak correlation in time and space).

[0094] This difference provides a basis for using mathematical tools (such as singular value decomposition) to separate the two types of signals.

[0095] In this embodiment of the invention, if singular value decomposition is directly performed on the ultrasound sequence image, it is easily affected by large blood vessels and physiological movements, which may result in the loss of some microvascular information. To solve this problem, this embodiment of the invention divides the ultrasound sequence image into multiple spatiotemporal sub-blocks. Each spatiotemporal sub-block may include some temporal dimension data and some spatial dimension data of the ultrasound sequence image, and there is partial overlap in the temporal and spatial dimension data of two adjacent spatiotemporal sub-blocks. After segmentation, the influence of large blood vessels and physiological movements on the data can be reduced. The overlap in data between adjacent spatiotemporal sub-blocks can reflect the continuity of blood flow, thus preserving the continuity and intrinsic relationship of the ultrasound sequence image.

[0096] Step 103: Perform singular value decomposition on all spatiotemporal sub-blocks, extract contrast agent signals, and obtain contrast agent sequence images corresponding to ultrasound sequence images based on contrast agent signals;

[0097] Singular Value Decomposition (SVD) is a linear algebraic method that decomposes a matrix into three submatrices: (Left singular vector): Represents spatial features (such as pixel position relationships); (Singular value matrix): A diagonal matrix where singular values ​​are arranged in descending order, representing the principal component energy of the data; (Right singular vector): Represents temporal features (such as inter-frame variations). Its core idea is to extract the primary patterns (corresponding to large singular values) and secondary patterns (corresponding to small singular values) from the data using SVD, thereby separating signals with different levels of coherence.

[0098] In this embodiment of the invention, a high-coherence signal (tissue) exhibits slow changes or periodic patterns in a time series, with energy concentrated in a few principal components (large singular values). A low-coherence signal (contrast agent) manifests as rapid random motion, with energy dispersed among multiple small singular values. The components corresponding to the singular vectors exhibit high-frequency, unstructured characteristics.

[0099] Therefore, this embodiment of the invention can perform singular value decomposition on all spatiotemporal sub-blocks to extract contrast agent signals, and then obtain contrast agent sequence images corresponding to ultrasound sequence images based on the contrast agent signals. In step 101, the ultrasound sequence image is composed of multiple ultrasound images in consecutive frames, which includes the echo situation of contrast agent in microvessels within a preset continuous time. In steps 102-103, the echo situation of contrast agent in microvessels within the preset continuous time is extracted from the ultrasound sequence image through a series of methods to obtain the contrast agent sequence image.

[0100] Step 104: Map the contrast agent sequence image to Hough space, locate the center point of the contrast agent signal based on Hough transform, and generate the center point of all microbubbles.

[0101] Localization of the contrast agent center point is the core of the imaging algorithm. Current methods based on Gaussian point spread function models and radial symmetry require numerous image frames, resulting in long acquisition and post-processing times. The contrast agent center point localization method proposed in this invention utilizes the Hough transform to locate the geometric center. The Hough transform is a feature extraction method that maps the original image to Hough space. Points on the same curve in the original image correspond to a series of intersecting surfaces in Hough space. Therefore, pixels on the same curve in the original image can be output based on these intersecting surfaces in Hough space. Thus, the contrast agent sequence image can be mapped to Hough space, and the contour curve of each microbubble can be obtained based on the Hough transform. The center point of each microbubble can then be derived from its contour.

[0102] Examples of processing the ultrasound sequence data in steps 102 to 104 are as follows: Figure 2 As shown.

[0103] Step 105: Perform microvascular imaging based on the center point of the microbubble.

[0104] In this embodiment of the invention, the distribution of microbubbles represents the distribution of microvessels. For example, the distribution of microvessels can be obtained by fitting the center points of all microbubbles. Based on this, the velocity of the microbubble center points can also be calculated to obtain the blood flow velocity.

[0105] As can be seen, the microvascular imaging method based on ultrasound phased array in this embodiment of the invention can acquire ultrasound sequence images, segment the ultrasound sequence images into multiple spatiotemporal sub-blocks, perform singular value decomposition on all spatiotemporal sub-blocks to extract contrast agent signals, map the contrast agent sequence images to Hough space, locate the center points of the contrast agent signals based on Hough transform, generate the center points of all microbubbles, and finally perform microvascular imaging operations. Segmenting the ultrasound sequence images into multiple spatiotemporal sub-blocks reduces the adverse effects of large blood vessels and physiological movements on the data. The overlapping data in adjacent spatiotemporal sub-blocks reflects the continuity of blood flow. The localization algorithm based on Hough transform has advantages such as requiring less data and having a faster processing speed, thereby reducing the data volume dependence in the microvascular imaging process and improving imaging efficiency.

[0106] In an optional embodiment, each ultrasonic element in the ultrasonic phased array can be selected to emit ultrasonic waves at different preset time intervals, thereby emitting spherical waves with a point source. Spherical waves have the advantages of wide detection range and focusing capability. Although the detection range of spherical waves is improved, the corresponding accuracy will decrease. Therefore, this application proposes a scheme of superimposing multiple spherical waves, which improves the detection range without sacrificing detection accuracy.

[0107] Specifically, the aforementioned ultrasound phased array acquires a series of microvascular ultrasound image data at a preset position and within a preset continuous time period, which may include:

[0108] Within a preset continuous time period, spherical wave transmission operations are performed multiple times. Each spherical wave transmission operation may include: the ultrasonic phased array sequentially emits virtual spherical waves, and after each virtual spherical wave transmission, all ultrasonic array elements simultaneously receive the scattered echo signals. After coherently superimposing all the scattered echo signals, ultrasonic image data is obtained.

[0109] Based on the ultrasound image data obtained from each spherical wave emission operation, a series of microvascular ultrasound image data are obtained.

[0110] In this optional embodiment, each virtual spherical wave emitted by the ultrasonic phased array corresponds to a different virtual point source. All virtual point sources have a preset positional relationship so that different virtual spherical waves can detect different directions, thereby obtaining detection data in each direction and improving the detection range. Each detection direction is executed separately, thus improving the detection range without sacrificing detection accuracy.

[0111] Examples of solutions in this optional embodiment are illustrated below:

[0112] Within a preset continuous time period, spherical wave emission operations are performed multiple times. Each spherical wave emission operation may include: the ultrasonic phased array sequentially emitting virtual spherical waves with centerline angles of -30 degrees, 0 degrees, and 30 degrees. After each virtual spherical wave emission, all ultrasonic array elements simultaneously receive the scattered echo signals. The three scattered echo signals with centerline angles of -30 degrees, 0 degrees, and 30 degrees are coherently superimposed to obtain ultrasonic image data. The detection angle of this ultrasonic image data exceeds 60 degrees and is composed of three high-precision echo data superimposed, containing more refined echo signals.

[0113] In the above optional embodiments, obtaining ultrasound image data by coherently superimposing all scattered echo signals still requires a certain amount of computation. For example, when coherently superimposing scattered echo signals with centerline angles of -30 degrees, 0 degrees and 30 degrees, the ultrasound image data at the overlapping area needs to be identified first, and then the data is combined based on the coherence relationship.

[0114] To address the technical challenge of high computational complexity in the coherent superposition process, in another optional embodiment, the virtual point source may include first-order and second-order virtual point sources. All first-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all first-order virtual point sources can be focused on the imaging origin. Similarly, all second-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all second-order virtual point sources can also be focused on the imaging origin. Furthermore, the distance from the first-order virtual point source to the ultrasonic phased array is less than the distance from the second-order virtual point source to the ultrasonic phased array.

[0115] In this optional embodiment, the closer the virtual point source is to the phased array, the larger the detection angle, such as... Figure 3 As shown, the detection angle of virtual point source B, which is closer to the phased array, is greater than that of virtual point source A, which is farther from the phased array. However, the larger the detection angle, the smaller the effective data density.

[0116] In this embodiment of the invention, the scattered echo signals corresponding to all first-order virtual point sources can be focused onto the imaging origin, and the scattered echo signals corresponding to all second-order virtual point sources can also be focused onto the imaging origin. Optionally, the second-order virtual point source is a plurality of uniformly distributed points parallel to the ultrasonic phased array, or at least one uniformly distributed point parallel to the ultrasonic phased array. In a preferred embodiment, there is only one second-order virtual point source located directly at the imaging origin, such as... Figure 4 As shown.

[0117] Furthermore, each spherical wave emission operation may include:

[0118] An ultrasonic phased array sequentially emits virtual spherical waves corresponding to first-order virtual point sources. After each virtual spherical wave emission, all ultrasonic array elements simultaneously receive the scattered echo signals. The scattered echo signals are then coherently superimposed to obtain a superimposed reference frame. Generally, the number of first-order point sources should be small. When there are only two first-order point sources, they can be two corresponding to the centerline positions of -60 degrees and 60 degrees. When there is only one first-order point source, coherent superposition is unnecessary to obtain the superimposed reference frame.

[0119] An ultrasonic phased array sequentially emits virtual spherical waves corresponding to second-order virtual point sources. After each virtual spherical wave emission, all ultrasonic array elements simultaneously receive the scattered echo signals. All scattered echo signals are then added to a superposition reference frame to obtain ultrasonic image data. Typically, there are many second-order point sources. For example, to obtain more detailed echo data, a spherical wave can be emitted every 10 degrees from -60 degrees to 60 degrees. In this case, when summarizing the data, there is no need to perform coherent superposition; only the two spherical waves at -60 degrees and 60 degrees need to be coherently superimposed. Then, the echo data corresponding to the second-order virtual point sources is added to the superposition reference frame to obtain the summarized data, i.e., the ultrasonic image data.

[0120] As can be seen, this optional embodiment, by designing a first-order virtual point source as a reference, reduces the computational load of coherent superposition of echo data corresponding to a second-order virtual point source.

[0121] In yet another alternative embodiment, the operation of the ultrasonic phased array emitting virtual spherical waves each time may include:

[0122] Each ultrasonic array element arranged in a straight line emits ultrasonic waves at its own preset time point, so that the ultrasonic waves emitted by the ultrasonic phased array are equivalent to spherical waves emitted from a virtual point source.

[0123] In this optional embodiment, spherical waves can be emitted by a time-delayed transmission method. It is known that sound waves emitted from the same point will experience a delay when they reach a certain plane. Utilizing this principle, spherical waves can be simulated by setting different arrays to emit ultrasonic waves with different time delays.

[0124] Optional, such as Figure 5 As shown, several virtual point sources can be set behind the ultrasonic array. Each virtual point source can be used as a sound source, and the emission of spherical waves can be controlled by setting different delays. The delay of the i-th array element can be expressed by the following formula:

[0125]

[0126]

[0127] Wherein, the coordinates of the virtual point source are ,like Figure 6 As shown, the coordinates of the i-th transducer element are... d represents the distance from the surface of the virtual point source transducer. Let be the distance from the current array element to the virtual point source, and c be the speed of sound in the specific medium. This is the delay for the i-th array element.

[0128] In yet another optional embodiment, the number of pixels in each frame of the ultrasound sequence is 100. That is, the spatial dimension, while the temporal dimension corresponding to ultrasound sequence images is... ;

[0129] Furthermore, segmenting ultrasound sequence images into multiple spatiotemporal sub-blocks may include:

[0130] The ultrasound sequence image is segmented into multiple spatiotemporal sub-blocks, and the spatial dimension data corresponding to any one spatiotemporal sub-block is: The time dimension data corresponding to any spatiotemporal sub-block is ;in , , Furthermore, there is some overlap between the time dimension data and the spatial dimension data of two adjacent spatiotemporal sub-blocks.

[0131] In this embodiment of the invention, the contrast agent is fluid, and within the time dimension of ultrasound detection, the flowing contrast agent remains at almost the same position in the ultrasound image. Therefore, this application employs a block-based operation, where the contrast agent signal corresponding to the same part of the microvessels is processed only in a small block, and there is an overlap between the time dimension data and the spatial dimension data between two consecutive spatiotemporal sub-blocks, thereby preserving the inherent connection of information.

[0132] In another optional embodiment, mapping the contrast agent sequence image to Hough space and locating the center point of the contrast agent signal based on the Hough transform to generate the center points of all microbubbles may include:

[0133] The contrast agent sequence images are mapped to Hough space so that points on the same curve in each frame of the contrast agent image correspond to a series of intersecting surfaces in Hough space.

[0134] Output the set of contour points corresponding to the same microbubble signal in each frame of contrast agent image based on the surfaces intersecting the same curve in Hough space;

[0135] For each microbubble signal in each frame of the contrast agent image, the center point of the contrast agent is considered to be the weighted centroid of the image. Therefore, the microbubble center point corresponding to the microbubble signal can be calculated using the following formula. :

[0136]

[0137]

[0138] Where N is the number of contour points in the contour point set corresponding to the microbubble signal. This refers to the i-th contour point within the contour point set corresponding to the microbubble signal. For the i-th contour point The corresponding normalized pixel value.

[0139] In yet another alternative embodiment, performing microvascular imaging based on the microbubble center point may include:

[0140] Trajectory tracking is performed on the center point of microbubbles in each frame of contrast agent image to obtain multiple microbubble trajectories corresponding to the contrast agent sequence image;

[0141] By superimposing all the microbubble trajectories corresponding to the contrast agent sequence images, a microvascular distribution image is obtained.

[0142] In this optional embodiment, further optionally, tracing the trajectory of the microbubble center point in each frame of the contrast agent image may include:

[0143] Multiple feature pixels in each frame of the contrast agent image are identified. These feature pixels are located at the edge of the microvessel contour. Because there are fewer pixels at the contour edge and they are more easily identifiable, selecting pixels at the contour edge can more efficiently select feature points.

[0144] A preset number of neighboring pixels are obtained around each feature pixel. For each feature pixel, a feature shape is fitted based on the feature pixel and its corresponding neighboring pixels. This optional embodiment does not search for the nearest pixel in the next frame as a matching point for a single pixel, but rather combines multiple pixels around the feature pixel to achieve matching of multiple pixels. Because the interval between two adjacent frames is short, the combination formed by multiple pixels has not been destroyed or deformed during the flow of the contrast agent. Therefore, matching the shape formed by multiple pixels is more accurate than matching a single pixel.

[0145] For each feature pattern in each frame of contrast agent image, similar feature patterns corresponding to each feature pattern are identified in the adjacent frames of contrast agent images corresponding to that frame. Generally, in two frames within a short time interval, the feature patterns change little with the flow of contrast agent and can be easily identified.

[0146] Based on the similar feature patterns corresponding to each feature pattern in all frames of contrast agent images, the trajectory corresponding to each feature point is determined.

[0147] Example 2

[0148] Based on Embodiment 1, Embodiment 2 of the present invention specifically discloses a method for achieving functional imaging of intracardiac structures and rapid myocardial microcirculation using interventional ultrasound catheters. The present invention aims to provide accurate and effective guidance for the diagnosis of structural heart disease and cardiac electrophysiological surgery, and can provide diagnosis, treatment and postoperative monitoring solutions for myocardial microcirculation-related diseases.

[0149] Currently, commonly used clinical imaging methods for the circulatory system include CTA, MRA, DSA, and Doppler ultrasound imaging. However, these methods are limited by the physical diffraction limit and the human body's radiation tolerance, making it impossible to accurately visualize the microvascular system at the micrometer scale. Ultrasound super-resolution microvascular imaging (SR) technology fills this gap. Existing SR imaging techniques rely on acquiring multiple spatiotemporal sequences of images over a long period and require a considerable amount of time to reconstruct the microvessels in the tissue profile. On the other hand, the heart is unique compared to other tissues because it is constantly beating, making it difficult to obtain high spatiotemporal coherence image sequences over a long period. Furthermore, the heart is surrounded by the sternum at a considerable depth, thus requiring a trade-off between imaging depth and imaging resolution. Generally, the imaging frequency is lower, making it even more difficult to capture the flowing contrast agent signal.

[0150] This invention mainly comprises two parts: signal acquisition and signal and image post-processing. Image acquisition utilizes ultrafast spherical wave coherent composite emission to acquire ultrasound sequence images, which are then transferred to memory via USB. In the signal and image post-processing part, singular value decomposition is first used to extract contrast agent signals with low spatiotemporal coherence. Then, a novel fast contrast agent center point localization algorithm based on Hough transform is used to depict the microbubble trajectory. The main principle of Hough transform is to transform a two-dimensional graphic into Hough space, where points in the original image space correspond to curves in Hough space, thus transforming the problem into a shape detection problem. The Hough transform-based shape localization algorithm has advantages such as requiring less data and having a fast post-processing speed. Tracking the contrast agent center point of each frame obtained above generates multiple trajectories. Finally, superimposing all trajectories yields the myocardial microvessel distribution, and the center point tracking results can be used in conjunction with contrast agent and hemodynamic parameters.

[0151] The following is a detailed description of the embodiments of the present invention:

[0152] (1) Data collection

[0153] Traditional line-scan imaging methods strike a trade-off between imaging resolution (line density and number of focal points) and imaging frame rate. As a result, the frame rate of traditional ultrasound imaging is limited to less than 100 frames per second. For clinical applications that require continuous tracking, line-scan focusing imaging cannot meet the needs.

[0154] Plane wave coherent composite imaging transmits multiple unfocused beams through electronic delay control. Each transmission receives echo data from all array elements simultaneously, and beam synthesis is performed using a delay superposition algorithm. This allows for the acquisition of ultrasound images at each angle. Due to the coherence of the echo signals, coherent composite of multi-angle plane wave data can improve the image signal-to-noise ratio and imaging frame rate.

[0155] A schematic diagram of the micro-phased array used to detect myocardium in an embodiment of the present invention is shown below. Figure 7 As shown.

[0156] However, due to the limited deflection capability of plane waves and the small aperture of the micro phased array, the imaging angle of plane wave composite ultrafast ultrasound imaging is very small.

[0157] To expand the imaging range, this embodiment of the invention employs spherical wave coherent composite imaging. Several virtual point sources are positioned behind the ultrasonic array, each of which can act as a sound source. By setting different delays, the emission of spherical waves can be controlled. Figure 5 As shown. The delay of the i-th array element can be expressed by the following formula.

[0158]

[0159]

[0160] Among them, such as Figure 6 As shown, the coordinates of the virtual point source are The coordinates of the i-th transducer element are d represents the distance from the surface of the virtual point source transducer. Let be the distance from the current array element to the virtual point source, and c be the speed of sound in the specific medium. This is the delay for the i-th array element.

[0161] Specifically, after each transmission, all array elements simultaneously receive the echo data, which is then beamformed and orthogonally demodulated to obtain a set of ultrasound image data. By changing the coordinates of the virtual point source, another set of coherent echo data can be obtained. Repeating the above transmission yields several sets of data, which are then coherently superimposed to obtain a high-quality ultrasound image.

[0162] Data acquisition is affected by the data transmission and storage capabilities of the imaging system. It is optional, and generally 1,000 frames are acquired per group, for example, 10 groups of ultrasound sequence images with a total of 1,000 frames are acquired.

[0163] (2) Singular Value Decomposition Filtering:

[0164] Because tissue and contrast agent signals have different spatiotemporal coherence, tissue corresponds to a high spatiotemporal coherence signal in the image sequence, while contrast agent signals correspond to a low spatiotemporal coherence signal. Therefore, singular value decomposition can be used to separate them.

[0165] Traditional wall filtering algorithms based on singular value decomposition are susceptible to the effects of large blood vessels and physiological movements, potentially losing some microvascular information. To address this, in this embodiment of the invention, the image pixels are... The time dimension is For example, each time series contains 1000 frames of mode B images. The entire time series is divided into several segments of size [missing information]. The sub-blocks, in which , , The sub-blocks overlap in both the horizontal (X) and axial (Z) directions. A two-dimensional matrix is ​​reconstructed for each sub-block, with the first dimension representing space and the other representing time. Singular value decomposition is then performed on this matrix using the following formula:

[0166]

[0167] here It is the two-dimensional decomposition matrix of the nth sub-block, where U and V are respectively The matrix spanned by the singular value vectors of space and time. It is a singular value matrix. This represents the conjugate transpose of a matrix.

[0168] Optionally, to remove background tissue signals and suppress noise, two preset thresholds were selected, with the point where the second derivative of the singular value energy curve is the largest being the lower-order threshold. Higher-order threshold It can be determined by the flatness of the curve slope.

[0169] Microbubble signal for each pixel for:

[0170]

[0171] Where N is the number of target pixels. The total number of overlapping sub-blocks, It is the flowing contrast agent signal of the nth sub-block. This refers to the contrast agent signal corresponding to the remaining singular values. The embodiments of this invention can effectively reduce the influence of large-diameter blood vessels and physiological motion signals on microvascular signals, thereby improving the accuracy and detection rate of microvascular imaging.

[0172] (3) Localization of the center point of the contrast agent signal

[0173] The localization of the contrast agent's center point is the core of the imaging algorithm. Currently used localization methods based on the Gaussian model of the point spread function and radial symmetry require a large number of image frames, as well as long acquisition and post-processing times.

[0174] This invention proposes a novel method for locating the contrast agent center: using Hough transform to locate the geometric center. Hough transform is a feature extraction method that maps the original image to Hough space. Points on the same curve in the original image correspond to a series of intersecting surfaces in Hough space. Therefore, pixels on the same curve in the original image can be output based on these intersecting surfaces in Hough space. The Hough transform can be used to find the contrast agent contour. The next step is to find the contrast agent center point, which is generally considered to be the weighted centroid of the image. The set of points within the contrast agent contour is... Its center of mass The following methods can be used to calculate,

[0175]

[0176]

[0177] Where N is the number of points. For the i-th contour point Normalized pixel values.

[0178] (4) Contrast agent center point tracking and particle velocimetry

[0179] The above method uses the Hough transform to obtain the center point of the contrast agent. Next, it is tracked to discard isolated noise points and obtain the particle flow velocity.

[0180] In this embodiment of the invention, we consider the microbubbles in the second frame that are closest to the center of the microbubbles in the first frame as the pairings of the microbubbles in the first frame, and mark the paired microbubbles accordingly. Then, we pair the microbubbles in the first frame sequentially. Finally, we pair the center points of the microbubbles in the preceding and following frames by minimizing the pairing distance. To minimize signal errors as much as possible, we set the minimum number of tracking frames to 5, that is, we discard the microbubble trajectories obtained from tracking less than 5 consecutive frames.

[0181] Furthermore, the velocity of the i-th microbubble can be measured sequentially.

[0182]

[0183] in It is the reciprocal of the frame rate. This refers to the velocity of the microbubbles in the first frame. Using this algorithm, the blood flow velocity within biological tissue can be obtained. This embodiment of the invention features fast operation, enables hemodynamic monitoring, and has a simple algorithm that is easy to understand and implement.

[0184] Example 3

[0185] This invention discloses a microvascular imaging device based on an ultrasound phased array. This device can be communicatively connected to an ultrasound phased array, which may include multiple ultrasound array elements arranged in a straight line. The device may include:

[0186] The data acquisition module is used to acquire ultrasound sequence images, wherein the ultrasound sequence images are a series of microvascular ultrasound image data acquired by an ultrasound phased array at a preset position and within a preset continuous time. The ultrasound image data may include at least contrast agent echoes.

[0187] The data segmentation module is used to segment ultrasound sequence images into multiple spatiotemporal sub-blocks. Each spatiotemporal sub-block can include part of the time dimension data and part of the spatial dimension data of the ultrasound sequence image, and there is partial overlap between the time dimension data and spatial dimension data of two adjacent spatiotemporal sub-blocks.

[0188] The data decomposition module is used to perform singular value decomposition on all spatiotemporal sub-blocks, extract contrast agent signals, and obtain contrast agent sequence images corresponding to ultrasound sequence images based on contrast agent signals.

[0189] The center point localization module is used to map the contrast agent sequence image to the Hough space, locate the center point of the contrast agent signal based on the Hough transform, and generate the center point of all microbubbles.

[0190] The imaging module is used for microvascular imaging based on the center point of the microbubble.

[0191] In an optional embodiment, the ultrasound phased array acquires a series of microvascular ultrasound image data at a preset location and within a preset continuous time period, which may include:

[0192] Within a preset continuous time period, spherical wave transmission operations are performed multiple times. Each spherical wave transmission operation may include: the ultrasonic phased array sequentially emits virtual spherical waves, and after each virtual spherical wave transmission, all ultrasonic array elements simultaneously receive the scattered echo signals. After coherently superimposing all the scattered echo signals, ultrasonic image data is obtained.

[0193] Based on the ultrasound image data obtained from each spherical wave emission operation, a series of microvascular ultrasound image data are obtained;

[0194] In this system, each virtual spherical wave emitted by the ultrasonic phased array corresponds to a different virtual point source, and all virtual point sources have a preset positional relationship so that different virtual spherical waves can detect different directions.

[0195] In another optional embodiment, the virtual point source may include a first-order virtual point source and a second-order virtual point source, wherein all first-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all first-order virtual point sources can be focused on the imaging origin; all second-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all second-order virtual point sources can also be focused on the imaging origin; and the distance from the first-order virtual point source to the ultrasonic phased array is less than the distance from the second-order virtual point source to the ultrasonic phased array.

[0196] Furthermore, each spherical wave emission operation may include:

[0197] The ultrasonic phased array sequentially emits virtual spherical waves corresponding to the first-order virtual point sources. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. The superimposed reference frame is obtained by coherently superimposing all the scattered echo signals.

[0198] The ultrasonic phased array sequentially emits virtual spherical waves corresponding to second-order virtual point sources. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. After adding all the scattered echo signals to the superimposed reference frame, ultrasonic image data is obtained.

[0199] In yet another alternative embodiment, the operation of the ultrasonic phased array emitting virtual spherical waves each time may include:

[0200] Each ultrasonic array element arranged in a straight line emits ultrasonic waves at its own preset time point, so that the ultrasonic waves emitted by the ultrasonic phased array are equivalent to spherical waves emitted from a virtual point source.

[0201] In yet another alternative embodiment,

[0202] The number of pixels in each frame of an ultrasound sequence image is [number]. The time dimension corresponding to the ultrasound sequence images is ;

[0203] Furthermore, the specific operation method by which the data segmentation module segments ultrasound sequence images into multiple spatiotemporal sub-blocks may include:

[0204] The ultrasound sequence image is segmented into multiple spatiotemporal sub-blocks, and the spatial dimension data corresponding to any one spatiotemporal sub-block is: The time dimension data corresponding to any spatiotemporal sub-block is ;in , , Furthermore, there is some overlap between the time dimension data and the spatial dimension data of two adjacent spatiotemporal sub-blocks.

[0205] In another optional embodiment, the center point localization module maps the contrast agent sequence image to Hough space, performs center point localization on the contrast agent signal based on the Hough transform, and generates the specific operation of all microbubble center points, which may include:

[0206] The contrast agent sequence images are mapped to Hough space so that points on the same curve in each frame of the contrast agent image correspond to a series of intersecting surfaces in Hough space.

[0207] Output the set of contour points corresponding to the same microbubble signal in each frame of contrast agent image based on the surfaces intersecting the same curve in Hough space;

[0208] For each microbubble signal in each frame of the contrast agent image, the center point of the microbubble corresponding to that microbubble signal is calculated according to the following formula. :

[0209]

[0210]

[0211] Where N is the number of contour points in the contour point set corresponding to the microbubble signal. This refers to the i-th contour point within the contour point set corresponding to the microbubble signal. For the i-th contour point The corresponding normalized pixel value.

[0212] In yet another optional embodiment, the imaging module performs microvascular imaging based on the microbubble center point, which may include:

[0213] Trajectory tracking is performed on the center point of microbubbles in each frame of contrast agent image to obtain multiple microbubble trajectories corresponding to the contrast agent sequence image;

[0214] By superimposing all the microbubble trajectories corresponding to the contrast agent sequence images, a microvascular distribution image is obtained.

[0215] Example 4

[0216] Please see Figure 8 , Figure 8 This is a schematic diagram of the structure of a microvascular imaging system based on an ultrasound phased array, as disclosed in an embodiment of the present invention. Figure 8 As shown, the ultrasound phased array-based microvascular imaging system may include:

[0217] Memory 201 storing executable program code;

[0218] Processor 202 coupled to memory 201;

[0219] The processor 202 calls the executable program code stored in the memory 201 to execute the steps in the microvascular imaging method based on ultrasound phased array described in Embodiment 1 or Embodiment 2 of the present invention.

[0220] Example 5

[0221] This invention discloses a computer storage medium storing computer instructions, which, when invoked, are used to execute the steps in the microvascular imaging method based on ultrasound phased array described in Embodiment 1 or Embodiment 2 of this invention.

[0222] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0223] Through the detailed description of the above embodiments, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, including read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-Erasable Programmable Read-Only Memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc storage, disk storage, magnetic tape storage, or any other computer-readable medium that can be used to carry or store data.

[0224] Finally, it should be noted that the microvascular imaging method and system based on ultrasound phased array disclosed in the embodiments of the present invention are merely preferred embodiments of the present invention, and are only used to illustrate the technical solutions of the present invention, not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A microvascular imaging method based on ultrasound phased array, characterized in that, The ultrasonic phased array comprises multiple ultrasonic array elements arranged in a straight line, and the method includes: Acquire ultrasound sequence images; The ultrasound sequence image is divided into multiple spatiotemporal sub-blocks. Each spatiotemporal sub-block includes part of the time dimension data and part of the spatial dimension data of the ultrasound sequence image. Furthermore, there is partial overlap between the time dimension data and spatial dimension data of two adjacent spatiotemporal sub-blocks. Singular value decomposition is performed on all the spatiotemporal sub-blocks to extract the contrast agent signal, and the contrast agent sequence image corresponding to the ultrasound sequence image is obtained based on the contrast agent signal. The contrast agent sequence image is mapped to Hough space, and the center point of the contrast agent signal is located based on the Hough transform to generate the center point of all microbubbles. Microvascular imaging is performed based on the center point of the microbubble. The ultrasound sequence images are obtained through the following operations: Within a preset continuous time period, spherical wave emission operations are performed multiple times. Each spherical wave emission operation includes: the ultrasonic phased array sequentially emits virtual spherical waves corresponding to the first-order virtual point source; after each virtual spherical wave emission, all ultrasonic array elements simultaneously receive the scattered echo signals; and after coherently superimposing all the scattered echo signals, a superimposed reference frame is obtained. The ultrasonic phased array sequentially emits virtual spherical waves corresponding to second-order virtual point sources. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. After adding all the scattered echo signals to the superimposed reference frame, ultrasonic image data is obtained. The ultrasonic image data includes at least contrast agent echoes. Based on the ultrasound image data obtained from each spherical wave emission operation, a series of microvascular ultrasound image data are obtained; The virtual point sources include first-order virtual point sources and second-order virtual point sources. All first-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all first-order virtual point sources can be focused on the imaging origin. All second-order virtual point sources also have a preset positional relationship so that the scattered echo signals corresponding to all second-order virtual point sources can also be focused on the imaging origin. Furthermore, the distance from the first-order virtual point source to the ultrasonic phased array is less than the distance from the second-order virtual point source to the ultrasonic phased array.

2. The microvascular imaging method based on ultrasound phased array according to claim 1, characterized in that, The operation of the ultrasonic phased array emitting virtual spherical waves each time includes: Each of the linearly arranged ultrasonic array elements emits ultrasonic waves at its own preset time point, so that the ultrasonic waves emitted by the ultrasonic phased array are equivalent to spherical waves emitted from a virtual point source.

3. The microvascular imaging method based on ultrasound phased array according to claim 1, characterized in that, The number of pixels in each frame of the ultrasound sequence image is The time dimension corresponding to the ultrasound sequence images is ; And, the step of segmenting the ultrasound sequence image into multiple spatiotemporal sub-blocks includes: The ultrasound sequence image is segmented into multiple spatiotemporal sub-blocks, and the spatial dimension data corresponding to any one spatiotemporal sub-block is: The time dimension data corresponding to any spatiotemporal sub-block is ;in , , Furthermore, there is some overlap between the time dimension data and the spatial dimension data of two adjacent spatiotemporal sub-blocks.

4. The microvascular imaging method based on ultrasound phased array according to any one of claims 1-3, characterized in that, The process of mapping the contrast agent sequence image to Hough space, locating the center point of the contrast agent signal based on the Hough transform, and generating the center points of all microbubbles includes: The contrast agent sequence images are mapped to Hough space so that points on the same curve in each frame of the contrast agent image correspond to a series of intersecting surfaces in Hough space. Output the set of contour points corresponding to the same microbubble signal in each frame of contrast agent image based on the surfaces intersecting the same curve in Hough space; For each microbubble signal in each frame of the contrast agent image, the center point of the microbubble corresponding to that microbubble signal is calculated according to the following formula. : Where N is the number of contour points in the contour point set corresponding to the microbubble signal. This refers to the i-th contour point within the contour point set corresponding to the microbubble signal. For the i-th contour point The corresponding normalized pixel value.

5. The microvascular imaging method based on ultrasound phased array according to any one of claims 1-3, characterized in that, The microvascular imaging operation based on the microbubble center point includes: Trajectory tracking is performed on the center point of microbubbles in each frame of contrast agent image to obtain multiple microbubble trajectories corresponding to the contrast agent sequence image; The microvessel distribution image is obtained by superimposing all the microbubble trajectories corresponding to the contrast agent sequence image.

6. A microvascular imaging device based on ultrasound phased array, characterized in that, The ultrasonic phased array comprises multiple ultrasonic array elements arranged in a straight line, and the device includes: The data acquisition module is used to acquire ultrasound sequence images; The data segmentation module is used to segment the ultrasound sequence image into multiple spatiotemporal sub-blocks. Each spatiotemporal sub-block includes part of the time dimension data and part of the spatial dimension data of the ultrasound sequence image, and there is partial overlap between the time dimension data and spatial dimension data of two adjacent spatiotemporal sub-blocks. The data decomposition module is used to perform singular value decomposition on all the spatiotemporal sub-blocks, extract the contrast agent signal, and obtain the contrast agent sequence image corresponding to the ultrasound sequence image based on the contrast agent signal. The center point localization module is used to map the contrast agent sequence image to the Hough space, locate the center point of the contrast agent signal based on the Hough transform, and generate the center point of all microbubbles. The imaging module is used to perform microvascular imaging based on the center point of the microbubble; The ultrasound sequence images are obtained through the following operations: Within a preset continuous time period, spherical wave emission operations are performed multiple times. Each spherical wave emission operation includes: the ultrasonic phased array sequentially emits virtual spherical waves corresponding to the first-order virtual point source; after each virtual spherical wave emission, all ultrasonic array elements simultaneously receive the scattered echo signals; and after coherently superimposing all the scattered echo signals, a superimposed reference frame is obtained. The ultrasonic phased array sequentially emits virtual spherical waves corresponding to second-order virtual point sources. After each virtual spherical wave is emitted, all ultrasonic array elements simultaneously receive the scattered echo signals. After adding all the scattered echo signals to the superimposed reference frame, ultrasonic image data is obtained. The ultrasonic image data includes at least contrast agent echoes. Based on the ultrasound image data obtained from each spherical wave emission operation, a series of microvascular ultrasound image data are obtained; The virtual point sources include first-order virtual point sources and second-order virtual point sources. All first-order virtual point sources have a preset positional relationship so that the scattered echo signals corresponding to all first-order virtual point sources can be focused on the imaging origin. All second-order virtual point sources also have a preset positional relationship so that the scattered echo signals corresponding to all second-order virtual point sources can also be focused on the imaging origin. Furthermore, the distance from the first-order virtual point source to the ultrasonic phased array is less than the distance from the second-order virtual point source to the ultrasonic phased array.

7. A microvascular imaging system based on ultrasound phased array, characterized in that, The system includes: a memory storing executable program code; a processor coupled to the memory; the processor calls the executable program code stored in the memory to execute the microvascular imaging method based on ultrasound phased array as described in any one of claims 1-5.

8. A computer storage medium, characterized in that, The computer storage medium stores computer instructions, which, when invoked, are used to execute the microvascular imaging method based on ultrasound phased array as described in any one of claims 1-5.

Images