A method for synchronously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor

Abstract

The application is a method for synchronously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor. The application relates to the technical field of medical ultrasonic sensor detection, and aims to solve the problems that the existing detection method is difficult to obtain a continuous blood pressure waveform, the blood flow detection equipment is inconvenient to wear for a long time, and blood pressure and blood flow parameters are difficult to be synchronously acquired under the same time reference. The application utilizes the characteristics that the flexible ultrasonic array sensor is well combined with the curved surface of the human body, synchronously acquires information such as blood vessel wall movement, blood vessel diameter change and blood flow velocity through the emission and reception of multi-element ultrasonic signals in the same detection process, and combines a blood flow dynamics model or individualized calibration parameters to realize continuous, non-invasive and synchronous detection of blood flow parameters and blood pressure parameters.

Description

Technical Field

[0001] This invention relates to the field of medical ultrasound sensor detection technology, and is a method for simultaneously detecting blood flow and blood pressure information based on a flexible ultrasound array sensor. Background Technology

[0002] Blood pressure and blood flow are important physiological parameters for assessing cardiovascular function, together reflecting vascular elasticity, cardiac pumping function, and peripheral circulation. While traditional cuff-based blood pressure measurement is widely used, it typically only allows for intermittent measurements, making it difficult to obtain continuous, real-time blood pressure waveforms. Blood flow information acquisition relies heavily on traditional ultrasound and Doppler flowmeters, which suffer from drawbacks such as large equipment size, complex operation, reliance on specialized personnel, and unsuitability for long-term continuous monitoring. Therefore, existing detection methods struggle to simultaneously acquire blood pressure and blood flow information at the same time frame, and thus fail to comprehensively reflect the dynamic hemodynamic changes of the cardiovascular system.

[0003] Currently, continuous blood pressure monitoring technologies mainly include photoplethysmography (PPG), pressure sensing, and arterial tension-based methods. These methods typically estimate blood pressure indirectly based on peripheral pulse waveforms, changes in skin surface pressure, or arterial compression. They are susceptible to individual differences in vascular elasticity, sensor contact conditions, and motion interference, and their measurement stability and long-term reliability still need improvement. Furthermore, existing blood pressure and blood flow monitoring methods are relatively independent in terms of sensing principles, equipment form, and data acquisition methods, making it difficult to simultaneously obtain continuous blood pressure waveforms, blood flow velocity, and blood flow rate. This limits their application in perioperative monitoring, intensive care, exercise monitoring, sleep monitoring, and early screening for cardiovascular diseases.

[0004] Therefore, there is a need for a non-invasive detection method that can conform to the curvature of the human body, support long-term stable wear, and simultaneously acquire blood flow and blood pressure parameters under a unified time reference, in order to meet the needs of continuous, wearable, and dynamic hemodynamic monitoring. Summary of the Invention

[0005] This invention addresses the problems of existing detection methods, such as the difficulty in obtaining continuous blood pressure waveforms, the inconvenience of long-term wear of blood flow detection devices, and the difficulty in synchronously acquiring blood pressure and blood flow parameters at the same time reference. This invention discloses a method for synchronously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor. This method utilizes the excellent fit of the flexible ultrasonic array sensor to the curved surface of the human body. Through the transmission and reception of multi-element ultrasonic signals, it synchronously acquires information such as blood vessel wall movement, changes in blood vessel diameter, and blood flow velocity during the same detection process. Combined with hemodynamic models or individualized calibration parameters, it achieves continuous, non-invasive, and synchronous detection of blood flow and blood pressure parameters.

[0006] This invention provides the following technical solutions: A method for simultaneously detecting blood flow and blood pressure information based on a flexible ultrasound array sensor, the method comprising the following steps: Step 1: Using a timing control method that combines multiple ultrasound transmissions and multi-channel reception, multiple ultrasound transducer elements in the flexible ultrasound array sensor are sequentially controlled to transmit ultrasound based on a unified clock signal, and multiple elements are controlled to synchronously receive ultrasound echo signals returned from the target blood vessel region, so that the blood vessel wall motion information, blood vessel diameter change information, and blood scattering echo information are all under the same time reference. Step 2: Within one acquisition cycle, multiple sets of transmission signals are generated sequentially. Each set of transmission signals corresponds to a different transmission angle, transmission aperture, or transmission array element combination. After each transmission, multiple receiving array elements simultaneously receive the echo signal, forming multiple sets of raw ultrasonic radio frequency data. Step 3: Perform delay compensation, dynamic focusing and beamforming processing on each group of echo signals, and coherently composite the image information obtained under different transmission conditions to generate a B-mode ultrasound image of the target blood vessel region, identify the anterior wall, posterior wall and lumen region of the blood vessel, and obtain structural information on the location of the blood vessel wall, the diameter of the blood vessel and the cross-sectional area of ​​the blood vessel. Step 4: Repeat the B-mode acquisition process continuously at the preset frame rate to obtain a B-mode image sequence covering at least one cardiac cycle. By tracking the changes in the position of the blood vessel wall, obtain the waveforms of changes in blood vessel diameter and cross-sectional area. Combine the reference systolic pressure and reference diastolic pressure obtained from the cuff blood pressure monitor, establish a blood pressure calculation model based on the pressure-area relationship, and calculate the continuous blood pressure waveform. Step 5: Accumulate multiple sets of echo data within multiple consecutive B-mode acquisition cycles. For each set of echo data, perform receiving beam synthesis according to the preset receiving deflection angle to form velocity mode data corresponding to different sound beam directions. Calculate the blood flow velocity projection components in different sound beam directions. Obtain the axial component, transverse component, synthesized velocity magnitude, and blood flow direction of the blood flow velocity in the blood vessel lumen through vector solving. Step 6: Spatial registration of the blood flow velocity vector distribution with the vascular lumen region in the B-mode image, extraction of the velocity component along the main flow direction of the blood vessel, and calculation of instantaneous blood flow based on the cross-sectional area of ​​the blood vessel.

[0007] Preferably, the flexible ultrasonic array sensor comprises, from bottom to top, a flexible acoustic coupling layer substrate, an acoustic matching layer, an ultrasonic transducer element, interconnecting electrodes, and an acoustic backing layer; The flexible acoustic coupling layer substrate is used to form a stable acoustic coupling with the surface of human skin, conforming to the curvature of the human body; The acoustic matching layer is used to reduce the acoustic impedance mismatch of ultrasound at the interface between the sensor and human tissue. The ultrasonic transducer array is used to realize the mutual conversion between electrical signals and ultrasonic mechanical vibration signals. The interconnecting electrodes are used to electrically connect each ultrasonic transducer element to an external module. The acoustic backing layer is used to absorb the ultrasonic energy propagating backward and suppress excess vibration and echo interference.

[0008] Preferably, the position of the anterior wall of the blood vessel is set as follows: z f (t) The location of the posterior wall of the blood vessel is z b (t) Then the instantaneous diameter of the blood vessel is: (1) The cross-sectional area of ​​the blood vessel is: (2) The above formula reflects the expansion and contraction of blood vessels under pulse pressure, serving as the input for blood pressure calculation.

[0009] Preferably, a reference systolic blood pressure p is obtained using a cuff blood pressure monitor before each measurement begins. s and reference diastolic pressure p d Let A be the minimum cross-sectional area of ​​the blood vessel during diastole. d The maximum cross-sectional area of ​​the blood vessel during systole is A. s A blood pressure calculation model was established based on the pressure-area relationship: (3) (4) Wherein, α is an individualized calibration parameter, determined by the cuff calibration results.

[0010] Preferably, for the first i One receiving direction, i =1, 2, 3, calculate the velocity projection in this direction based on the phase change of the echo signals from adjacent frames: (5) (6) in, S i (r, t ) indicates the first i Each receiving direction at position r and time t The signal at that location, where 'c' represents the speed of sound in human tissue. f 0 represents the center frequency of the ultrasound, Δ t Indicates the time interval between adjacent frames. v i (r, t) represents the Doppler velocity projection in that direction; The three sets of velocity projections are written as follows: (7) in, v θ1 , v θ2 and v θ3 These represent the Doppler velocity projections measured under three different sound beam directions.

[0011] Preferably, when the average blood flow velocity within the blood vessel cross-section is v mean (t), then the instantaneous blood flow is expressed as: (8) in, Q(t) Indicates instantaneous blood flow. A(t) This represents the cross-sectional area of ​​the blood vessel obtained from the B-mode image.

[0012] Preferably, the acquisition time for each frame of B-mode image is approximately 200 μs.

[0013] Preferably, by comparing the changes in the position of the blood vessel wall in adjacent frames or multiple frames of B-mode images, the displacement changes of the blood vessel wall with the cardiac cycle, the waveform of the changes in blood vessel diameter, and the changes in blood vessel cross-sectional area are obtained.

[0014] A computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement a method for synchronously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor.

[0015] A computer device includes a memory and a processor, the memory storing a computer program, and the processor executing the computer program to implement a method for synchronously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor.

[0016] The present invention has the following beneficial effects: This invention uses a flexible ultrasonic array sensor that can conform to the curved areas of the human body, such as the wrist, neck, and upper arm, to achieve stable fit and long-term continuous detection.

[0017] This invention utilizes the same flexible ultrasound array sensor, the same set of multi-angle ultrasound transmission and multi-channel reception data to simultaneously obtain B-mode vascular structure information and vector Doppler blood flow information, ensuring that blood flow parameters and blood pressure parameters are under a unified time reference.

[0018] This invention continuously tracks the position of the anterior and posterior walls of blood vessels using B-mode images to obtain the waveforms of the vessel diameter and cross-sectional area, and calculates continuous blood pressure waveforms by combining cuff blood pressure calibration parameters, thereby achieving non-invasive continuous blood pressure detection.

[0019] This invention reconstructs the blood flow velocity vector by using multi-directional velocity projection data corresponding to Tx1 / Rx1, Tx2 / Rx2, and Tx3 / Rx3, thereby obtaining the magnitude and direction of blood flow velocity. Compared with single-angle Doppler measurement, it can better reflect the true blood flow state.

[0020] This invention combines the vascular cross-sectional area obtained from B-mode and the average blood flow velocity obtained from vector Doppler to calculate instantaneous blood flow, thereby enabling the simultaneous output of various hemodynamic parameters such as vascular structure, blood pressure waveform, blood flow velocity, blood flow direction, and blood flow. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the flexible ultrasonic array sensor used in this invention; Figure 2 This is a schematic diagram of the flexible ultrasonic array sensor attached to a target blood vessel area in the human body for detection in this invention; Figure 3 This is a schematic diagram of multi-angle ultrasonic transmission, multi-channel reception, B-mode image reconstruction, and vector Doppler synchronous processing in this invention. in, Figure 3 (A) is a schematic diagram of the echo data obtained by multiple receiving array elements after the first plane wave transmitted signal Tx1 is transmitted; Figure 3 (B) is a schematic diagram of the echo data obtained by multiple receiving array elements after the second plane wave transmitted signal Tx2 is transmitted; Figure 3 (C) is a schematic diagram of the echo data obtained by multiple receiving array elements after the third plane wave transmitted signal Tx3 is transmitted; Figure 3 (D) is a schematic diagram of the B-mode image reconstruction and vector Doppler synchronous processing flow in this invention; Figure 4 This is a flowchart of the B-mode image reconstruction and blood pressure waveform calculation process in this invention; Figure 5 This is a flowchart illustrating the calculation of vector Doppler blood flow velocity and blood flow rate in this invention. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0024] The present invention will be described in detail below with reference to specific embodiments. Specific Implementation Example 1: according to Figures 1 to 5 As shown, the specific optimized technical solution adopted by the present invention to solve the above-mentioned technical problems is: The present invention relates to a method for synchronously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor.

[0026] This invention provides a method for simultaneously detecting blood flow and blood pressure information based on a flexible ultrasound array sensor, the method comprising the following steps: This invention provides the following technical solutions: A method for synchronously detecting blood flow and blood pressure information based on a flexible ultrasound array sensor, the method comprising the following steps.

[0027] The flexible ultrasonic array sensor involved in this invention is mainly composed of a flexible acoustic coupling layer substrate, an acoustic matching layer, ultrasonic transducer elements, interconnecting electrodes, and an acoustic backing layer.

[0028] The flexible acoustic coupling layer substrate serves as a flexible support structure for the sensor, forming a stable acoustic coupling with the human skin surface during detection. This allows the sensor to conform well to the curves of the human body, such as the wrist, neck, and upper arm. An acoustic matching layer is positioned between the ultrasonic transducer elements and the human tissue to reduce acoustic impedance mismatch at the sensor-tissue interface, improving the transmission and reception efficiency of the ultrasonic signal. The ultrasonic transducer elements are used to convert between electrical signals and ultrasonic mechanical vibration signals. Interconnect electrodes electrically connect each ultrasonic transducer element to external excitation, control, and signal acquisition modules, enabling independent, time-division, or collaborative driving of the elements. An acoustic backing layer is located on the side of the ultrasonic transducer elements furthest from the detection surface, absorbing rearward-propagating ultrasonic energy and suppressing unwanted vibrations and echo interference, thereby improving the axial resolution and stability of the detection signal.

[0029] The above describes the basic structure and working principle of the flexible ultrasonic array sensor. Based on this flexible ultrasonic array sensor, the present invention can simultaneously acquire blood flow and blood pressure parameters under a unified time reference. The method flow is as follows: Step 1: This invention employs a timing control method combining multiple ultrasonic transmissions and multi-channel reception for detection. The flexible ultrasonic array sensor includes multiple ultrasonic transducer elements. During detection, the external excitation and control module sequentially controls the ultrasonic transducer elements in the array to transmit ultrasound based on a unified clock signal, and controls multiple elements to synchronously receive the ultrasonic echo signals returned from the target blood vessel region.

[0030] By using a unified clock signal to synchronously control ultrasound transmission, echo reception, analog-to-digital conversion, beamforming, and subsequent B-mode imaging and velocity mode processing, the information on blood vessel wall motion, blood vessel diameter changes, and blood scattering echoes are all under the same time reference.

[0031] Step 2: Within one acquisition cycle, the control module sequentially generates multiple sets of transmission signals, such as the first plane wave transmission signal Tx1, the second plane wave transmission signal Tx2, and the third plane wave transmission signal Tx3 shown in the figure. Tx1, Tx2, and Tx3 can correspond to different transmission angles, transmission apertures, or combinations of transmission array elements, respectively. After each transmission, multiple receiving array elements in the array simultaneously receive echo signals from human tissue, blood vessel walls, and blood scatterers, thus forming signals such as... Figure 3 (A) Figure 3 (B) and Figure 3 (C) shows the multi-element received data. The vertical axis in the figure represents the element number, and the horizontal axis represents the echo reception time. The echo signals received by different elements under the same transmission event together constitute a set of original ultrasonic radio frequency data.

[0032] Step 3: After completing the three transmissions (Tx1, Tx2, and Tx3) and corresponding echo reception, the signal processing module performs delay compensation, dynamic focusing, and beamforming on each set of echo signals. It also coherently composites the image information obtained at different transmission angles or apertures to generate a single frame of B-mode ultrasound image of the target blood vessel region. This B-mode image can be used to identify the anterior wall, posterior wall, and lumen of the blood vessel, thereby obtaining structural information such as the vessel wall location, vessel diameter, and cross-sectional area. Figure 3 (D) As shown on the left, each frame of the B-mode image is formed by combining multiple transmitted echo data. In this embodiment, the acquisition time for each frame of the B-mode image is approximately 200 μs.

[0033] The acquisition time for each V-mode frame is 18ms (the vector flow velocity is obtained from 30 B-mode images). The purpose of this invention is to simultaneously obtain blood flow and blood pressure information using the same set of data. A human cardiac cycle is approximately 0.8s-1.0s. 200μs (B-mode) is generally sufficient to capture the dynamic changes in blood pressure within a complete cardiac cycle. 18ms per frame (V-mode) is generally sufficient to capture the dynamic changes in blood flow within a complete cardiac cycle.

[0034] Step 4: During continuous detection, the above-mentioned B-mode acquisition process is repeated continuously at a preset frame rate to obtain a B-mode image sequence covering at least one or more cardiac cycles. By comparing the changes in the position of the blood vessel wall in adjacent or multiple frames of B-mode images, the displacement changes of the blood vessel wall with the cardiac cycle, the waveform of changes in blood vessel diameter, and the changes in blood vessel cross-sectional area can be obtained.

[0035] Let the location of the anterior wall of the blood vessel be... z f (t) The location of the posterior wall of the blood vessel is z b (t) Then the instantaneous diameter of the blood vessel is: (1) The cross-sectional area of ​​the blood vessel is: (2) The above parameters reflect the expansion and contraction of blood vessels under pulse pressure and can serve as important inputs for blood pressure calculation.

[0036] Before each measurement, a reference systolic blood pressure (p) can be obtained using a cuff blood pressure monitor. s and reference diastolic pressure p d Let A be the minimum cross-sectional area of ​​the blood vessel during diastole. d The maximum cross-sectional area of ​​the blood vessel during systole is A. s A blood pressure calculation model can then be established based on the pressure-area relationship: (3) Wherein, α is an individualized calibration parameter, which can be determined from the cuff calibration results: (4) Step 5: According to the preset velocity estimation window, accumulate multiple sets of raw ultrasound radio frequency data or multiple frames of B-mode image data within multiple consecutive B-mode acquisition cycles. Each preset number of accumulated B-mode data forms a set of velocity estimation data. Perform receive beamforming on this set of velocity estimation data according to different receive deflection angles or different beam directions to obtain velocity pattern data corresponding to multiple beam directions. Calculate the blood flow velocity projection components in different beam directions, and obtain the axial and transverse components of the intravascular blood flow velocity, as well as the magnitude and direction of the synthesized velocity, through vector solving.

[0037] In blood flow velocity pattern processing, for the echo data corresponding to Tx1, Tx2, and Tx3, the signal processing module performs receive beamforming according to a preset receive deflection angle to form velocity pattern data of Rx1, Rx2, and Rx3. Rx1, Rx2, and Rx3 correspond to blood scattering echo information under different sound beam directions. The post-processing module calculates the Doppler frequency shift, phase change, or inter-frame shift in different sound beam directions to obtain the projection components of blood flow velocity in multiple sound beam directions. Since the Doppler velocity obtained in a single Rx direction is only a projection of the true blood flow velocity in that sound beam direction, it cannot completely characterize the magnitude and direction of blood flow velocity. Therefore, this invention utilizes... Figure 3 (D) shows three sets of velocity projection data in different directions, Rx1, Rx2 and Rx3, to establish the vector Doppler solution relationship.

[0038] Specifically, the post-processing module, based on the geometric relationship between the receiving deflection directions of Rx1, Rx2, and Rx3 and the sensor coordinate system, projects the Doppler velocities measured in each direction as projections of the true blood flow velocity vectors onto the corresponding sound beam directions. Then, through vector decomposition, weighted fusion, or least squares solving, it obtains the axial and transverse components of the intravascular blood flow velocity, as well as the magnitude and direction of the synthesized velocity. Thus, the post-processing module outputs as follows: Figure 3 (D) A frame velocity pattern image or blood flow velocity vector distribution result shown on the right.

[0039] Within a vector Doppler velocity calculation time window of approximately 18 ms, the post-processing module performs time-series analysis on the blood scattering echo signals corresponding to Rx1, Rx2, and Rx3 in 90 consecutive frames. For the first... i One receiving direction, i =1, 2, 3, the velocity projection in this direction can be calculated based on the phase change of the echo signals from adjacent frames: (5) (6) in, S i (r, t ) indicates the first i Each receiving direction at position r and time t The signal at that location, where 'c' represents the speed of sound in human tissue. f 0 represents the center frequency of the ultrasound, Δ t Indicates the time interval between adjacent frames. v i (r, t ) represents the Doppler velocity projection in that direction.

[0040] θ1, θ2, and θ3 can be different receiving deflection directions, different transmit-receive combination directions, or equivalent sound beam directions determined by both the transmit and receive directions. In this scheme, Tx1 / Rx1, Tx2 / Rx2, and Tx3 / Rx3 correspond to the three directions θ1, θ2, and θ3, respectively. The three sets of velocity projections can then be written as: (7) in, v θ1 , v θ2 and v θ3 These represent the Doppler velocity projections measured under three different sound beam directions. Based on these three sets of velocity projection relationships, the post-processing module calculates the transverse component of the blood flow velocity using the least squares method, weighted least squares method, or other equivalent solution methods. v x and axial component v z .

[0041] Step 6: Figure 3 (D) The B-mode processing channel on the left coherently composites the same set of Tx1, Tx2, and Tx3 echo data to generate corresponding B-mode images, used to identify the anterior and posterior walls of the blood vessel and the vascular lumen boundary, obtaining changes in vessel diameter and cross-sectional area. The post-processing module spatially registers the blood flow velocity vector distribution obtained from vector Doppler with the vascular lumen region in the B-mode image, extracts the velocity component along the main flow direction of the blood vessel, and calculates the instantaneous blood flow rate by combining it with the vascular cross-sectional area. If the average blood flow velocity within the vessel cross-section is v... mean (t), then the instantaneous blood flow can be expressed as: (8) in, Q(t) Indicates instantaneous blood flow. A(t) This represents the cross-sectional area of ​​the blood vessel obtained from the B-mode image.

[0042] In summary, since both the B-mode structural information and the vector Doppler blood flow information originate from the continuously acquired Tx1, Tx2, and Tx3 plane wave transmissions and their corresponding multi-channel reception data under the same time reference, and are all acquired and processed under a unified clock signal, the information on changes in vessel diameter, vessel wall displacement, changes in vessel cross-sectional area, blood pressure waveform, blood flow velocity vector, blood flow direction, and blood flow rate are temporally correlated. This ensures that the blood flow measurement results and the vascular structural parameters required for blood pressure calculation are under a unified time reference.

[0043] The above description is merely a preferred embodiment of a method for simultaneously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor. The scope of protection for this method is not limited to the above embodiments; all technical solutions falling within this conceptual framework are within the scope of protection of this invention. It should be noted that for those skilled in the art, any improvements and variations made without departing from the principles of this invention should also be considered within the scope of protection of this invention.

Claims

1. A method for simultaneously detecting blood flow and blood pressure information based on a flexible ultrasonic array sensor, characterized in that: The method includes the following steps: Step 1: Using a timing control method that combines multiple ultrasound transmissions and multi-channel reception, multiple ultrasound transducer elements in the flexible ultrasound array sensor are sequentially controlled to transmit ultrasound based on a unified clock signal, and multiple elements are controlled to synchronously receive ultrasound echo signals returned from the target blood vessel region, so that the blood vessel wall motion information, blood vessel diameter change information, and blood scattering echo information are all under the same time reference. Step 2: Within one acquisition cycle, multiple sets of transmission signals are generated sequentially. Each set of transmission signals corresponds to a different transmission angle, transmission aperture, or transmission array element combination. After each transmission, multiple receiving array elements simultaneously receive the echo signal, forming multiple sets of raw ultrasonic radio frequency data. Step 3: Perform delay compensation, dynamic focusing and beamforming processing on each group of echo signals, and coherently composite the image information obtained under different transmission conditions to generate a B-mode ultrasound image of the target blood vessel region, identify the anterior wall, posterior wall and lumen region of the blood vessel, and obtain structural information on the location of the blood vessel wall, the diameter of the blood vessel and the cross-sectional area of ​​the blood vessel. Step 4: Repeat the B-mode acquisition process continuously at the preset frame rate to obtain a B-mode image sequence covering at least one cardiac cycle. By tracking the changes in the position of the blood vessel wall, obtain the waveforms of changes in blood vessel diameter and cross-sectional area. Combine the reference systolic pressure and reference diastolic pressure obtained from the cuff blood pressure monitor, establish a blood pressure calculation model based on the pressure-area relationship, and calculate the continuous blood pressure waveform. Step 5: Accumulate multiple sets of echo data within multiple consecutive B-mode acquisition cycles. For each set of echo data, perform receiving beam synthesis according to the preset receiving deflection angle to form velocity mode data corresponding to different sound beam directions. Calculate the blood flow velocity projection components in different sound beam directions. Obtain the axial component, transverse component, synthesized velocity magnitude, and blood flow direction of the blood flow velocity in the blood vessel lumen through vector solving. Step 6: Spatial registration of the blood flow velocity vector distribution with the vascular lumen region in the B-mode image, extraction of the velocity component along the main flow direction of the blood vessel, and calculation of instantaneous blood flow based on the cross-sectional area of ​​the blood vessel.

2. The method according to claim 1, characterized in that: The flexible ultrasonic array sensor comprises, from bottom to top, a flexible acoustic coupling layer substrate, an acoustic matching layer, an ultrasonic transducer element, interconnecting electrodes, and an acoustic backing layer. The flexible acoustic coupling layer substrate is used to form a stable acoustic coupling with the surface of human skin, conforming to the curvature of the human body; The acoustic matching layer is used to reduce the acoustic impedance mismatch of ultrasound at the interface between the sensor and human tissue. The ultrasonic transducer array is used to realize the mutual conversion between electrical signals and ultrasonic mechanical vibration signals. The interconnecting electrodes are used to electrically connect each ultrasonic transducer element to an external module. The acoustic backing layer is used to absorb the ultrasonic energy propagating backward and suppress excess vibration and echo interference.

3. The method according to claim 2, characterized in that: Let the location of the anterior wall of the blood vessel be... z f (t) The location of the posterior wall of the blood vessel is z b (t) Then the instantaneous diameter of the blood vessel is: (1) The cross-sectional area of ​​the blood vessel is: (2) The above formula reflects the expansion and contraction of blood vessels under pulse pressure, serving as the input for blood pressure calculation.

4. The method according to claim 3, characterized in that: Before each measurement, obtain a reference systolic blood pressure (p) using a cuff blood pressure monitor. s and reference diastolic pressure p d Let A be the minimum cross-sectional area of ​​the blood vessel during diastole. d The maximum cross-sectional area of ​​the blood vessel during systole is A. s A blood pressure calculation model was established based on the pressure-area relationship: (3) (4) Wherein, α is an individualized calibration parameter, determined by the cuff calibration results.

5. The method according to claim 4, characterized in that: For the i One receiving direction, i =1, 2, 3, calculate the velocity projection in this direction based on the phase change of the echo signals from adjacent frames: (5) (6) in, S i (r, t ) indicates the first i Each receiving direction at position r and time t The signal at that location, where 'c' represents the speed of sound in human tissue. f 0 represents the center frequency of the ultrasound, Δ t Indicates the time interval between adjacent frames. v i (r, t ) represents the Doppler velocity projection in that direction; The three sets of velocity projections are written as follows: (7) in, v θ1 , v θ2 and v θ3 These represent the Doppler velocity projections measured under three different sound beam directions.

6. The method according to claim 5, characterized in that: When the average blood flow velocity within the cross-section of the blood vessel is v mean (t), then the instantaneous blood flow is expressed as: (8) in, Q(t) Indicates instantaneous blood flow. A(t) This represents the cross-sectional area of ​​the blood vessel obtained from the B-mode image.

7. The method according to claim 6, characterized in that: The acquisition time for each frame of B-mode image is approximately 200 μs.

8. The method according to claim 7, characterized in that: By comparing the changes in the position of the blood vessel wall in adjacent frames or multiple frames of B-mode images, the displacement changes of the blood vessel wall with the cardiac cycle, the waveform of the changes in blood vessel diameter, and the changes in blood vessel cross-sectional area are obtained.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method as claimed in any one of claims 1-8.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the method of any one of claims 1-8.

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