Bidirectional guided wave measurement device, method and storage medium

Abstract

The present application relates to the field of guided wave measurement technology, and more particularly to a bidirectional guided wave measurement device, method, and storage medium, wherein the device comprises: an ultrasonic measurement module for performing ultrasonic imaging of a target blood vessel along a long-axis section to obtain an ultrasonic image, programming the acoustic radiation force to simultaneously excite axial and circumferential guided wave signals from the upper and lower walls of the blood vessel, and collecting the signals to obtain an ultrasonic imaging sequence; a data processing module for identifying the ultrasonic image to obtain the vessel radius, extracting the spatiotemporal velocity field of the ultrasonic imaging sequence, extracting the bidirectional guided wave group velocity based on the vessel radius and the spatiotemporal velocity field, and performing mechanical property inversion based on the bidirectional guided wave group velocity to obtain the anisotropic mechanical properties of the blood vessel. Thus, the device solves the problems of poor measurement data stability, low data accuracy, high cost, and technical difficulties in simultaneously inverting the anisotropic mechanical properties of the blood vessel when simultaneously measuring axial and circumferential guided waves in the blood vessel in the related art.

Description

Technical Field

[0001] The present application relates to the field of guided wave measurement technology, and in particular to a bidirectional guided wave measurement device, method, and storage medium. Background Art

[0002] In recent years, cardiovascular disease has become the leading cause of death worldwide. Studies have shown that vascular wall lesions and their development are the direct causes of various cardiovascular complications, including myocardial infarction and stroke. Most vascular wall lesions can lead to alterations in arterial mechanical properties. Therefore, in vivo measurement of arterial mechanical properties is of great significance for the early screening and diagnosis of cardiovascular disease.

[0003] Vascular guided wave elastography (GWE) is a recently emerging technology for measuring vascular mechanical properties. This technique uses acoustic radiation forces to excite elastic waves in the vessel wall. These waves propagate within the vessel wall as guided waves. Ultrasonic plane wave rapid imaging techniques are then used to image and acquire signals, thereby acquiring wavefield information. Group velocity or phase velocity information is extracted from the wavefield and, combined with the dispersion model of guided wave theory, allows for characterization of vascular mechanical properties. Related technologies primarily perform ultrasound imaging along the longitudinal axis of the vessel and analyze its axial mechanical properties using GWE. However, research on GWE is limited, primarily due to limitations in imaging quality and signal acquisition. Therefore, characterizing GWE's circumferential mechanical properties remains challenging. Furthermore, blood vessels exhibit anisotropic mechanical properties (i.e., different mechanical properties in the circumferential and axial directions). While various imaging methods can only characterize the material in one direction, it is difficult to simultaneously characterize all of the anisotropy. Therefore, developing an imaging technique that can simultaneously measure both axial and circumferential GWE signals is of great value.

[0004] Related technologies have proposed a cross-type probe design scheme, which can achieve simultaneous measurement of axial guided waves and circumferential guided waves of blood vessels through two orthogonally arranged probes. However, the related technology has poor robustness in extracting the axial guided wave group velocity, especially when the blood vessels are in the contraction phase, the measurement is obviously inaccurate, and there are problems such as poor signal quality in the acquisition of circumferential guided waves. Summary of the Invention

[0005] The present application provides a bidirectional guided wave measurement device, method and storage medium to solve the problems in the related art of simultaneously measuring the axial guided wave and the circumferential guided wave of the blood vessel, such as poor measurement data stability, low data accuracy, high cost and technical difficulties in simultaneously inverting the anisotropic mechanical properties of the blood vessel.

[0006] A first aspect of the present application provides a bidirectional guided wave measurement device, comprising: an ultrasonic measurement module, configured to perform ultrasonic imaging of a blood vessel at a target location along a long-axis section to obtain an ultrasonic image, synchronously excite the upper and lower walls of the blood vessel wall through a programmed acoustic radiation force, so that the upper and lower walls of the blood vessel wall simultaneously excite axial guided wave signals and circumferential guided wave signals, and collect signals to obtain an ultrasonic imaging sequence; and a data processing module, configured to identify the ultrasonic image to obtain a blood vessel radius, extract a space-time velocity field of the ultrasonic imaging sequence, extract a bidirectional guided wave group velocity based on the blood vessel radius and the space-time velocity field, and perform mechanical property inversion based on the bidirectional guided wave group velocity to obtain anisotropic mechanical properties of the blood vessel.

[0007] Optionally, in one embodiment of the present application, the data processing module is further used to process the ultrasound imaging sequence using a preset algorithm to obtain a particle velocity field; and based on the position of the particle velocity field along the center lines of the upper wall and the lower wall of the blood vessel wall, a space-time velocity field is extracted, wherein the space-time velocity field is a blood vessel guided wave field excited by the acoustic radiation force, and also includes axial guided wave information and circumferential guided wave information.

[0008] Optionally, in one embodiment of the present application, the data processing module is further used to perform window filtering on the space-time velocity field to obtain a processed space-time velocity field; search point by point for the data point with the minimum velocity in the processed space-time velocity field, and calculate the axial guided wave group velocity by the least squares method based on the data point.

[0009] Optionally, in one embodiment of the present application, the axial guided wave group velocity c a The calculation formula is:

[0010]

[0011] in, represents the fitting coefficient, l i Indicates the position corresponding to the minimum point, t i Indicates the time corresponding to the minimum point, n indicates the total number, represents the average value of the location points, Indicates the average value of time.

[0012] Optionally, in one embodiment of the present application, the data processing module is further used to extract a time-velocity relationship curve at the acoustic radiation force excitation position along the length direction of the space-time velocity field; perform smoothing filtering optimization on the time-velocity relationship curve to obtain an optimized curve; identify the time corresponding to the minimum value in the optimized curve, perform time gain compensation on the time corresponding to the minimum value, obtain the circumferential guide wave arrival time, and calculate the circumferential guide wave group velocity based on the circumferential guide wave arrival time.

[0013] Optionally, in one embodiment of the present application, the circumferential waveguide group velocity c c The calculation formula is:

[0014] c c =πr / t c ,

[0015] Among them, t c =t1+t ARF +t NL represents the arrival time of the ring-guided wave, t1 represents the time corresponding to the minimum value, t ARF represents the acoustic radiation force excitation time, t NL represents the system waiting time, r represents the blood vessel radius, and π is the pi parameter.

[0016] Optionally, in one embodiment of the present application, the ultrasound measurement module includes: an ultrasound probe for performing ultrasound imaging of the blood vessels at the target location along the long axis section; an ultrasound host, the ultrasound host including a radio frequency receiving end, a radio frequency transmitting end and a focused acoustic radiation force end, for generating and emitting acoustic radiation force, synchronously exciting the upper and lower walls of the blood vessel wall, and receiving the excited axial guide wave signal and circumferential guide wave signal; an ultrasound system for controlling the ultrasound host to generate acoustic radiation force according to programming.

[0017] Optionally, in one embodiment of the present application, the inversion method includes any one of a theoretical model, a finite element model, and a neural network trained based on finite element results.

[0018] Optionally, in one embodiment of the present application, the excitation mode includes any one of simultaneous dual-point excitation, moving acoustic radiation force excitation and single-point acoustic radiation force excitation.

[0019] A second aspect of the present application provides a bidirectional waveguide measurement method, which is applied to the bidirectional waveguide measurement device as described in the above embodiment, and includes the following steps: performing ultrasonic imaging on the blood vessel at the target position along the long axis section to obtain an ultrasonic image, synchronously exciting the upper wall and the lower wall of the blood vessel wall through programmed acoustic radiation force, so that the upper wall and the lower wall of the blood vessel wall simultaneously excite axial waveguide signals and circumferential waveguide signals, and collecting signals to obtain an ultrasonic imaging sequence; identifying the ultrasonic image to obtain the blood vessel radius, extracting the space-time velocity field of the ultrasonic imaging sequence, extracting the bidirectional waveguide group velocity according to the blood vessel radius and the space-time velocity field, and performing mechanical property inversion based on the bidirectional waveguide group velocity to obtain the anisotropic mechanical properties of the blood vessel.

[0020] Optionally, in one embodiment of the present application, the extracting of the space-time velocity field of the ultrasound imaging sequence includes: processing the ultrasound imaging sequence using a preset algorithm to obtain a particle velocity field; extracting the space-time velocity field based on the position of the particle velocity field along the center lines of the upper wall and the lower wall of the blood vessel wall, wherein the space-time velocity field is a blood vessel guided wave field excited by the acoustic radiation force, and includes both axial guided wave information and circumferential guided wave information.

[0021] Optionally, in one embodiment of the present application, extracting the bidirectional guided wave group velocity based on the blood vessel radius and the space-time velocity field includes: performing window filtering on the space-time velocity field to obtain a processed space-time velocity field; searching point by point for the data point with the minimum velocity in the processed space-time velocity field, and calculating the axial guided wave group velocity based on the data point by the least squares method.

[0022] Optionally, in one embodiment of the present application, the axial guided wave group velocity c a The calculation formula is:

[0023]

[0024] in, represents the fitting coefficient, l i Indicates the position corresponding to the minimum point, t i Indicates the time corresponding to the minimum point, n indicates the total number, represents the average value of the location points, Indicates the average value of time.

[0025] Optionally, in one embodiment of the present application, the extracting of the bidirectional guided wave group velocity based on the blood vessel radius and the space-time velocity field includes: extracting a time-velocity relationship curve at the acoustic radiation force excitation position along the length direction of the space-time velocity field; performing smoothing filtering optimization on the time-velocity relationship curve to obtain an optimized curve; identifying the moment corresponding to the minimum value in the optimized curve, performing time gain compensation on the moment corresponding to the minimum value to obtain the circumferential guided wave arrival time, and calculating the circumferential guided wave group velocity based on the circumferential guided wave arrival time.

[0026] Optionally, in one embodiment of the present application, the circumferential waveguide group velocity c c The calculation formula is:

[0027] c c =πr / t c ,

[0028] Among them, t c =t1+t ARF +t NLrepresents the arrival time of the ring-guided wave, t1 represents the time corresponding to the minimum value, t ARF represents the acoustic radiation force excitation time, t NL represents the system waiting time, r represents the blood vessel radius, and π is the pi parameter.

[0029] A third aspect of the present application provides a computer-readable storage medium having a computer program stored thereon. The program is executed by a processor to implement the bidirectional guided wave measurement method as described in the above embodiment.

[0030] Therefore, this application has at least the following beneficial effects:

[0031] The ultrasound measurement module performs ultrasound imaging of the target blood vessel along its long axis, acquires a spatiotemporal wavefield diagram, and then combines this information with comprehensive analysis to obtain axial and circumferential waveguide signals. This eliminates the need for additional probe design and processing. The data processing module processes and analyzes the image data from the ultrasound module to obtain bidirectional waveguide group velocity and vascular mechanical parameters. The measurement algorithm is stable, the data is highly reliable, and is beneficial for clinical application. The inversion method also enables simultaneous characterization of the anisotropic mechanical properties of the blood vessels. This overcomes the problems of poor data stability, low data accuracy, high cost, and technical difficulties in simultaneously inverting the anisotropic mechanical properties of the blood vessels encountered in related technologies when simultaneously measuring axial and circumferential waveguides in blood vessels.

[0032] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0034] Figure 1 A block diagram of a bidirectional guided wave measurement device provided according to an embodiment of the present application;

[0035] Figure 2 This is an example diagram of the upper wall and lower wall of a blood vessel provided according to one embodiment of the present application;

[0036] Figure 3 This is an example diagram of a finite element model provided according to one embodiment of the present application;

[0037] Figure 4 A schematic diagram of iteratively correcting finite element model parameters according to one embodiment of the present application;

[0038] Figure 5 A schematic diagram of a designed ultrasound imaging sequence according to one embodiment of the present application;

[0039] Figure 6 A schematic diagram of extracting a vascular guided wave signal from a particle velocity field according to an embodiment of the present application;

[0040] Figure 7 This is an example diagram of blood vessel radius provided according to one embodiment of the present application;

[0041] Figure 8 A schematic diagram of axial guided wave group velocity extraction according to one embodiment of the present application;

[0042] Figure 9 A schematic diagram of extracting the circumferential guided wave group velocity according to an embodiment of the present application;

[0043] Figure 10 The figure is a flow chart of a bidirectional guided wave measurement method provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0044] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0045] The following describes a bidirectional waveguide measurement device, method, and storage medium according to an embodiment of the present application with reference to the accompanying drawings. In response to the problems mentioned in the above background technology, the present application provides a bidirectional waveguide measurement device, in which an ultrasonic measurement module is used to perform ultrasonic imaging of a target blood vessel along a long axis section, and after obtaining a wavefield spatiotemporal diagram, the axial waveguide and circumferential waveguide signals are obtained by comprehensive analysis based on the image information. No additional design or processing of the probe equipment is required. The image data from the ultrasonic module is processed by a data processing module, and the data is analyzed to obtain the bidirectional waveguide group velocity and the mechanical parameters of the blood vessel. The measurement algorithm is stable, the data reliability is high, and it is conducive to clinical application. The inversion method is used to achieve simultaneous characterization of the anisotropic mechanical properties of the blood vessel. Thus, the present application solves the problems of poor measurement data stability, low data accuracy, high cost, and technical difficulties in simultaneously inverting the anisotropic mechanical properties of the blood vessel when simultaneously measuring the axial waveguide and circumferential waveguide of the blood vessel in the related art.

[0046] Specifically, Figure 1 Schematic diagram of a bidirectional guided wave measurement device provided in an embodiment of the present application.

[0047] like Figure 1 As shown, the bidirectional guided wave measuring device 10 includes an ultrasonic measuring module 100 and a data processing module 200 .

[0048] Among them, the ultrasonic measurement module 100 is used to perform ultrasonic imaging of the blood vessel at the target position along the long axis section to obtain an ultrasonic image, and synchronously excite the upper and lower walls of the blood vessel wall through programmed acoustic radiation force, so that the upper and lower walls of the blood vessel wall simultaneously stimulate axial guided wave signals and circumferential guided wave signals, and collect signals to obtain an ultrasonic imaging sequence; the data processing module 200 is used to identify the ultrasonic image to obtain the blood vessel radius, extract the time-space velocity field of the ultrasonic imaging sequence, extract the two-way guided wave group velocity according to the blood vessel radius and the time-space velocity field, and perform mechanical property inversion based on the two-way guided wave group velocity to obtain the anisotropic mechanical properties of the blood vessel.

[0049] The data processing module in the embodiment of the present application is primarily composed of a computer and its installed software. It is responsible for processing and analyzing image data from the ultrasound module to obtain bidirectional guided wave group velocity and vascular mechanical parameters. The display and output module then displays the measured bidirectional guided wave group velocity and vascular bidirectional material parameters to the user. Multiple sets of measurement data are then displayed to the user in a statistical format.

[0050] It should be noted that, in principle, the present invention can be implemented on any superficial artery that can be measured by ultrasound (such as the radial artery, brachial artery, etc.). However, for ease of explanation, in the subsequent embodiments, the present invention will use a specific example of measuring the common carotid artery with bidirectional waveguides to describe the bidirectional waveguide measurement device of the present invention.

[0051] Specifically, the embodiment of the present application can use the ultrasound module 100 to perform ultrasound imaging of the blood vessels at the target location along the long-axis section, so that the upper and lower walls of the blood vessels under the ultrasound image can be clearly seen in the long-axis section, and the blood vessel wall is stimulated by the programmed acoustic radiation force, so that the upper and lower walls of the blood vessel wall are stimulated simultaneously or almost simultaneously. Figure 2 (b) shows a specific embodiment, which achieves (quasi-) synchronous excitation of the upper and lower walls of the blood vessel wall by moving the acoustic radiation force (number of focal points ≥ 3).

[0052] Furthermore, the embodiment of the present application realizes the excitation and signal acquisition of blood vessel bidirectional guided wave by designing an ultrasound imaging sequence. The overall process is as follows Figure 3 As shown, including the acoustic radiation force stage (t ARF ), blank period (t NL ), imaging acquisition phase (t IM). The blank phase is a blank period due to the power switching of the ultrasound system. The target function of the imaging acquisition phase is to collect the axial guide wave signal of the blood vessel. The data acquisition range should cover the position of the upper and lower walls of the blood vessel. The sampling frequency should be at least higher than 5kHz. The raw data collected can be I / Q data or RF data. In a specific embodiment, the embodiment of the present application can collect signals through plane wave fast imaging technology, and the sampling time t IM =4ms, the sampling frequency is 10kHz, so the sampling is 40 frames in total, and the time of other stages is t ARF =0.5ms,t NL =0.3ms.

[0053] In the embodiment of the present application, the anisotropic mechanical properties of the blood vessels are inverted by bidirectional guided wave group velocity. In a specific embodiment, the embodiment of the present application can establish a finite element model such as Figure 4 As shown in (a), the initial configuration is a circular tube with water as the inner and outer boundaries. Internal pressure (within the physiological range, such as 60mmHg-120mmHg) and axial tension (value range of 1.0-1.2) are applied to the circular tube, so that the geometry of the deformed circular tube is consistent with the blood vessel geometry measured in the experiment. Acoustic radiation force excitation is applied to one end of the circular tube to stimulate guided waves. The time-space velocity field along the axial direction is extracted from the finite element calculation results, as shown in Figure 4 As shown in (b), the axial guided wave group velocity c is obtained by fitting a and the circumferential wave group velocity c c . Through Figure 5 The iterative process shown iteratively modifies the parameters of the finite element model so that the finite element calculation results are consistent with the experimental measurement results, and the anisotropic mechanical properties of the blood vessels can be inverted to obtain the anisotropic mechanical properties of the blood vessels. This can be used to detect and evaluate arterial stiffness and has potential application value in the detection of diseases such as arteriosclerosis.

[0054] It should be noted that the specific excitation methods in the embodiments of the present application include but are not limited to: simultaneous dual-point excitation (focusing on the upper and lower walls of the blood vessel at the same time), moving acoustic radiation force excitation (multiple excitation sources are focused in sequence from the upper wall to the lower wall of the blood vessel), single-point acoustic radiation force excitation (adjusting the acoustic radiation force focusing radius to cover the upper and lower walls), etc.; specific technologies for implementing imaging acquisition include but are not limited to: plane wave rapid acquisition technology, A-line echo acquisition technology (requires at least three sampling points, namely the excitation origin, and two other points along the axis of the blood vessel); the inversion method can be a theoretical model, a finite element model, or a neural network trained based on finite element results, etc.

[0055] In one embodiment of the present application, the ultrasound measurement module 100 further includes: an ultrasound probe, an ultrasound host, and an ultrasound system.

[0056] Among them, the ultrasound probe is used to perform ultrasound imaging of the blood vessels at the target location along the long axis section; the ultrasound host includes a radio frequency receiving end, a radio frequency transmitting end and a focused acoustic radiation force end, which are used to generate and emit acoustic radiation force, synchronously excite the upper and lower walls of the blood vessel wall, and receive the excited axial guide wave signal and circumferential guide wave signal; the ultrasound system is used to control the ultrasound host to generate acoustic radiation force according to programming.

[0057] The ultrasound measurement module 100 of the embodiment of the present application is composed of an ultrasound host, an ultrasound system and an ultrasound probe. The ultrasound host includes a radio frequency receiving / transmitting end and a focused acoustic radiation force end. The ultrasound probe can be a common linear array probe (probe center frequency 5 to 15 MHz) or a dot array probe composed of multiple single array elements. Taking the measurement of the common carotid artery of a subject as an example, the embodiment of the present application uses an ultrasound probe to image the blood vessel along the long axis section. The ultrasound probe is gently placed on the skin surface to avoid squeezing the blood vessels. Figure 2 As shown in (a); the ultrasound system can realize brightness mode imaging, programmable acoustic radiation force excitation and high frame rate (>5kHz) acquisition functions.

[0058] In one embodiment of the present application, the data processing module 200 is further used to process the ultrasound imaging sequence using a preset algorithm to obtain a particle velocity field; based on the position of the particle velocity field along the center lines of the upper wall and the lower wall of the blood vessel wall, a space-time velocity field is extracted, wherein the space-time velocity field is a blood vessel guided wave field excited by the acoustic radiation force, and also includes axial guided wave information and circumferential guided wave information.

[0059] The preset algorithms include, but are not limited to, Loupas algorithm, Kasai algorithm, etc., which can be selected according to actual conditions without specific limitation.

[0060] Specifically, the embodiment of the present application can obtain I / Q data or RF data from the ultrasound system, and process the raw data through a preset algorithm to obtain the particle velocity field v x (x, z, t), and extract the vascular guided wave signal from the particle velocity field. Different extraction methods can be used for different imaging acquisition technologies. The core is to obtain at least the time-velocity curves of three particle positions along the axial direction of the upper and lower walls of the blood vessel (including the excitation origin and the other two points along the axial direction of the blood vessel). Figure 6 In a specific embodiment shown, plane wave acquisition technology can be used to obtain a particle velocity field within the imaging plane. Spatiotemporal velocity fields are extracted along the centerlines of the upper and lower blood vessel walls, with the origin of these extraction lines selected at the location of acoustic radiation force excitation. This spatiotemporal velocity field is the guided wave field generated by the acoustic radiation force, and it contains both axial and circumferential guided wave information.

[0061] Furthermore, the data processing module 200 of the embodiment of the present application can also obtain the radius of the blood vessel by synchronously collecting the B-ultrasound image of the blood vessel. Figure 7 A specific embodiment is shown, in which one frame out of 40 frames obtained by rapid imaging is selected (the first frame is selected in the embodiment of the present application), the B-mode image of the blood vessel is calculated using the IQ raw data, and the radius of the blood vessel is measured using the B-ultrasound image, and the radius is recorded as r.

[0062] During the actual execution process, the data processing method of the embodiment of the present application can be implemented through any programming software (such as MATLAB, Python, etc.) without specific limitation.

[0063] In one embodiment of the present application, the data processing module 200 is further used to perform window filtering on the space-time velocity field to obtain a processed space-time velocity field; point by point, search for the data point with the minimum velocity in the processed space-time velocity field, and calculate the axial guided wave group velocity based on the data point by the least squares method.

[0064] The embodiment of the present application can extract the axial guided wave group velocity, and the extraction method includes but is not limited to the Radon transform method, the cross-correlation method, etc. Specifically, the embodiment of the present application first performs a windowing operation on the particle velocity field, such as Figure 8 As shown in (a), the signals in the lower left corner (speed below a certain threshold, 2m / s in this embodiment) and the upper right corner (speed above a certain threshold, 15m / s in this embodiment) are set to zero, thereby filtering out interference signals. Then, along each fixed length direction, the corresponding time-speed curve is extracted and the minimum point on the curve is found, as shown in the figure. Figure 8 As shown in (b), in this way, the coordinates of a set of minimum points (l i ,t i ), i=1,2,…n, n represents the total amount of data. This set of data points is as follows Figure 8 As shown in (c), by fitting the data points with the least square method, the slope of the linear equation is obtained, and thus the group velocity c of the axial guided wave is obtained. a , the specific calculation formula is:

[0065]

[0066]

[0067] in represents the fitting coefficient, l i Indicates the position corresponding to the minimum point, t i Indicates the time corresponding to the minimum point, n indicates the total number, represents the average value of the location points, Indicates the average value of time.

[0068] In one embodiment of the present application, the data processing module 200 is further used to extract a time-velocity relationship curve at the acoustic radiation force excitation position along the length direction of the space-time velocity field; perform smoothing filtering optimization on the time-velocity relationship curve to obtain an optimized curve; identify the time corresponding to the minimum value in the optimized curve, perform time gain compensation on the time corresponding to the minimum value, obtain the arrival time of the circumferential guide wave, and calculate the circumferential guide wave group velocity based on the arrival time of the circumferential guide wave.

[0069] It is understood that the core of the extraction method for the circumferential guided wave group velocity is the detection of the echo time t1 of the particle at the excitation source and the gain compensation of the circumferential time. The following is an example to illustrate the point in time along the length direction. Figure 9 (a) The time-speed relationship curve is extracted from the position indicated by the dotted line, and the curve is smoothed and filtered. The specific implementation algorithm includes but is not limited to the moving average method, local regression method, Savitzky-Golay filter, etc. The obtained curve is shown in FIG. Figure 9 As shown in (b), the time corresponding to the minimum value is found on the curve and recorded as t1. Then time gain compensation is performed. The principle of compensation is to supplement the time from the blood vessel being excited to the start of the imaging acquisition phase, and finally the arrival time of the circular guide wave t c , that is, t c =t1+t ARF +t NL , and further, the group velocity c of the circumferential waveguide c Calculated by the following formula:

[0070] c c =πr / t c

[0071] Among them, t c =t1+t ARF +t NL represents the arrival time of the ring-guided wave, t1 represents the time corresponding to the minimum value, t ARF represents the acoustic radiation force excitation time, t NL represents the system waiting time, r represents the blood vessel radius, and π is the pi parameter.

[0072] It should be noted that the group velocity extraction methods of the circumferentially guided waves and the axially guided waves in the embodiments of the present application can be implemented by any programming software (such as MATLAB, Python, etc.) without specific limitation.

[0073] According to the bidirectional guided wave measurement device proposed in the embodiments of the present application, an ultrasonic measurement module is used to perform ultrasonic imaging of the target blood vessel along the long axis section. After obtaining a wavefield spatiotemporal diagram, the axial and circumferential guided wave signals are obtained by comprehensive analysis based on the image information. No additional design or processing of the probe equipment is required. The image data from the ultrasonic module is processed and analyzed by a data processing module to obtain the bidirectional guided wave group velocity and the mechanical parameters of the blood vessel. The measurement algorithm is stable and the data is highly reliable, which is beneficial for clinical application. The inversion method is used to achieve simultaneous characterization of the anisotropic mechanical properties of the blood vessel. This solves the problems of poor measurement data stability, low data accuracy, high cost, and technical difficulties in simultaneously inverting the anisotropic mechanical properties of the blood vessel when simultaneously measuring the axial and circumferential guided waves in the blood vessel in the related art.

[0074] Next, a flow chart of a bidirectional guided wave measurement method provided by an embodiment of the present application is described with reference to the accompanying drawings.

[0075] like Figure 10 As shown, the bidirectional waveguide measurement method is applied to the bidirectional waveguide measurement device as in the above embodiment, and includes the following steps:

[0076] In step S101, ultrasound imaging is performed on the blood vessel at the target location along the long axis section to obtain an ultrasound image. The upper and lower walls of the blood vessel wall are synchronously excited by the programmed acoustic radiation force, so that the upper and lower walls of the blood vessel wall simultaneously stimulate axial guided wave signals and circumferential guided wave signals, and the signals are collected to obtain an ultrasound imaging sequence.

[0077] In step S102, the ultrasound image is identified to obtain the blood vessel radius, the spatiotemporal velocity field of the ultrasound imaging sequence is extracted, the bidirectional guided wave group velocity is extracted based on the blood vessel radius and the spatiotemporal velocity field, and the mechanical properties are inverted based on the bidirectional guided wave group velocity to obtain the anisotropic mechanical properties of the blood vessel.

[0078] In one embodiment of the present application, extracting the space-time velocity field of an ultrasound imaging sequence includes: processing the ultrasound imaging sequence using a preset algorithm to obtain a particle velocity field; extracting the space-time velocity field based on the positions of the particle velocity field along the center lines of the upper wall and the lower wall of the blood vessel wall, wherein the space-time velocity field is a blood vessel guided wave field excited by the acoustic radiation force, and includes both axial guided wave information and circumferential guided wave information.

[0079] Optionally, in one embodiment of the present application, the bidirectional guided wave group velocity is extracted based on the blood vessel radius and the space-time velocity field, including: performing window filtering on the space-time velocity field to obtain a processed space-time velocity field; searching point by point for the data point with the minimum velocity in the processed space-time velocity field, and calculating the axial guided wave group velocity based on the data points by the least squares method.

[0080] Optionally, in one embodiment of the present application, the axial guided wave group velocity c a The calculation formula is:

[0081]

[0082] in, represents the fitting coefficient, l i Indicates the position corresponding to the minimum point, t i Indicates the time corresponding to the minimum point, n indicates the total number, represents the average value of the location points, Indicates the average value of time.

[0083] Optionally, in one embodiment of the present application, the bidirectional guided wave group velocity is extracted based on the blood vessel radius and the space-time velocity field, including: extracting a time-velocity relationship curve at the acoustic radiation force excitation position along the length direction of the space-time velocity field; performing smoothing filtering optimization on the time-velocity relationship curve to obtain an optimized curve; identifying the time corresponding to the minimum value in the optimized curve, performing time gain compensation on the time corresponding to the minimum value to obtain the circumferential guided wave arrival time, and calculating the circumferential guided wave group velocity based on the circumferential guided wave arrival time.

[0084] Optionally, in one embodiment of the present application, the circumferential waveguide group velocity c c The calculation formula is:

[0085] c c =πr / t c ,

[0086] Among them, t c =t1+t ARF +t NL represents the arrival time of the ring-guided wave, t1 represents the time corresponding to the minimum value, t ARF represents the acoustic radiation force excitation time, t NL represents the system waiting time, r represents the blood vessel radius, and π is the pi parameter.

[0087] It should be noted that the above explanation of the embodiment of the bidirectional waveguide measurement device is also applicable to the bidirectional waveguide measurement method of this embodiment, and will not be repeated here.

[0088] According to the bidirectional guided wave measurement method proposed in the embodiments of the present application, by performing ultrasound imaging of the target blood vessel along the long axis section and obtaining a wavefield space-time diagram, combined with image information for comprehensive analysis, axial and circumferential waveguide signals are obtained. No additional design or processing of the probe equipment is required. The ultrasound image data is analyzed to obtain the bidirectional guided wave group velocity and mechanical parameters of the blood vessel. The measurement algorithm is stable, the data is highly reliable, and it is beneficial for clinical application. The inversion method also enables simultaneous characterization of the anisotropic mechanical properties of the blood vessel. This solves the problems of poor measurement data stability, low data accuracy, high cost, and technical difficulties in simultaneously inverting the anisotropic mechanical properties of the blood vessel when simultaneously measuring axial and circumferential waveguides in the related art.

[0089] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, which implements the above-mentioned bidirectional guided wave measurement method when executed by a processor.

[0090] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0091] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this application, "N" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0092] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0093] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiment, the N steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array, a field programmable gate array, etc.

[0094] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0095] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A bidirectional guided wave measuring device, characterized in that: include: An ultrasonic measurement module is used to perform ultrasonic imaging of a target blood vessel along a long-axis section to obtain an ultrasonic image. The module uses programmed acoustic radiation force to synchronously excite the upper and lower walls of the blood vessel so that the upper and lower walls of the blood vessel simultaneously excite axial guided wave signals and circumferential guided wave signals, and collects the signals to obtain an ultrasonic imaging sequence. a data processing module, configured to identify the ultrasound image to obtain a blood vessel radius, extract a spatiotemporal velocity field of the ultrasound imaging sequence, extract a bidirectional guided wave group velocity based on the blood vessel radius and the spatiotemporal velocity field, and perform mechanical property inversion based on the bidirectional guided wave group velocity to obtain anisotropic mechanical properties of the blood vessel; The data processing module is further configured to: perform window filtering on the space-time velocity field to obtain a processed space-time velocity field; search point by point for a data point with the minimum velocity in the processed space-time velocity field, and calculate the axial guided wave group velocity using the least squares method based on the data point; The data processing module is further used to: extract a time-velocity relationship curve at the acoustic radiation force excitation position along the length direction of the space-time velocity field; perform smoothing filtering optimization on the time-velocity relationship curve to obtain an optimized curve; identify the time corresponding to the minimum value in the optimized curve, perform time gain compensation on the time corresponding to the minimum value to obtain the circumferential guide wave arrival time, and calculate the circumferential guide wave group velocity based on the circumferential guide wave arrival time.

2. The device according to claim 1, characterized in that The data processing module is further configured to: Processing the ultrasound imaging sequence using a preset algorithm to obtain a particle velocity field; Based on the positions of the particle velocity field along the center lines of the upper wall and the lower wall of the blood vessel wall, a space-time velocity field is extracted, wherein the space-time velocity field is a blood vessel guided wave field generated by the acoustic radiation force excitation, and contains both axial guided wave information and circumferential guided wave information.

3. The device according to claim 1, characterized in that The axial guided wave group velocity c a The calculation formula is: in, represents the fitting coefficient, l i Indicates the position corresponding to the minimum point, t i Indicates the time corresponding to the minimum point, n indicates the total number, represents the average value of the location points, Indicates the average value of time.

4. The device according to claim 1, characterized in that The circumferential waveguide group velocity c c The calculation formula is: c c =πr / t c , Among them, t c =t1+t ARF +t NL represents the arrival time of the ring-guided wave, t1 represents the time corresponding to the minimum value, t ARF represents the acoustic radiation force excitation time, t NL represents the system waiting time, r represents the blood vessel radius, and π is the pi parameter.

5. The device according to claim 1, characterized in that The ultrasonic measurement module includes: an ultrasound probe, used for performing ultrasound imaging of a blood vessel at a target location along a long axis section; An ultrasound host, comprising a radio frequency receiving end, a radio frequency transmitting end, and a focused acoustic radiation force end, for generating and emitting acoustic radiation force, synchronously exciting the upper and lower walls of the blood vessel wall, and receiving the excited axial guided wave signals and circumferential guided wave signals; The ultrasonic system is used to control the ultrasonic host to generate acoustic radiation force according to programming.

6. The device according to claim 1, characterized in that The inversion method includes any one of a theoretical model, a finite element model and a neural network trained based on finite element results.

7. The device according to claim 1, characterized in that The excitation mode includes any one of simultaneous dual-point excitation, moving acoustic radiation force excitation and single-point acoustic radiation force excitation.

8. A bidirectional guided wave measurement method, characterized in that: The method is applied to the bidirectional guided wave measurement device according to any one of claims 1 to 7, wherein the method comprises the following steps: Ultrasonic imaging is performed on the target blood vessel along the long axis section to obtain an ultrasound image. The upper and lower walls of the blood vessel wall are synchronously excited by programmed acoustic radiation force, so that the upper and lower walls of the blood vessel wall simultaneously excite axial guided wave signals and circumferential guided wave signals, and the signals are collected to obtain an ultrasound imaging sequence. Identifying the ultrasound image to obtain a blood vessel radius, extracting a spatiotemporal velocity field of the ultrasound imaging sequence, extracting a bidirectional guided wave group velocity based on the blood vessel radius and the spatiotemporal velocity field, and performing mechanical property inversion based on the bidirectional guided wave group velocity to obtain anisotropic mechanical properties of the blood vessel; The method of extracting the bidirectional guided wave group velocity based on the blood vessel radius and the space-time velocity field includes: performing window filtering on the space-time velocity field to obtain a processed space-time velocity field; searching point by point for the data point with the minimum velocity in the processed space-time velocity field, and calculating the axial guided wave group velocity based on the data point by the least squares method; and extracting a time-velocity relationship curve at the acoustic radiation force excitation position along the length direction of the space-time velocity field; performing smoothing filtering optimization on the time-velocity relationship curve to obtain an optimized curve; identifying the time corresponding to the minimum value in the optimized curve, performing time gain compensation on the time corresponding to the minimum value to obtain the circumferential guided wave arrival time, and calculating the circumferential guided wave group velocity based on the circumferential guided wave arrival time.

9. The method according to claim 8, characterized in that The extracting of the spatiotemporal velocity field of the ultrasound imaging sequence comprises: Processing the ultrasound imaging sequence using a preset algorithm to obtain a particle velocity field; Based on the positions of the particle velocity field along the center lines of the upper wall and the lower wall of the blood vessel wall, a space-time velocity field is extracted, wherein the space-time velocity field is a blood vessel guided wave field generated by the acoustic radiation force excitation, and contains both axial guided wave information and circumferential guided wave information.

10. The method according to claim 8, characterized in that The axial guided wave group velocity c a The calculation formula is: in, represents the fitting coefficient, l i Indicates the position corresponding to the minimum point, t i Indicates the time corresponding to the minimum point, n indicates the total number, represents the average value of the location points, Indicates the average value of time.

11. The method according to claim 8, characterized in that The circumferential waveguide group velocity c c The calculation formula is: c c =πr / t c , Among them, t c =t1+t ARF +t NL represents the arrival time of the ring-guided wave, t1 represents the time corresponding to the minimum value, t ARF represents the acoustic radiation force excitation time, t NL represents the system waiting time, r represents the blood vessel radius, and π is the pi parameter.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the bidirectional guided wave measurement method according to any one of claims 8 to 11.

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