A method for acoustic and electrical imaging with synchronous detection of multiple sites

Abstract

The invention relates to an acoustic and electric imaging method for synchronous detection of multiple sites, comprising the following steps: building a multi-focal spot acoustic and electric imaging system; adjusting the emission rule of a transducer for emitting ultrasound, designing a multi-focal spot array element emission mode, adopting an emission array element amplitude apodization mode, and forming multiple focused focal spot sites, respectively encoding electrical signals at corresponding sites; designing pulse repetition frequency characteristics; using the obtained multi-beam sound field with different pulse repetition frequencies to scan multiple sites in a target area, the beam forms a focal spot at a focal plane, and the multiple focal spots of the sound field will respectively encode electrical signals in corresponding areas to form encoded acoustic and electric signals; collecting the encoded acoustic and electric signals, filtering and decoding the collected signals; obtaining the decoded signal amplitude of each site; normalizing and interpolating the decoded signal amplitudes of all sites, and realizing acoustic and electric imaging based on multi-region combination and synchronous detection of multiple sites.

Description

Technical Field

[0001] The present invention relates to the technical field of neurological function imaging, and in particular to an acoustic and electrical imaging method for synchronous detection of multiple sites. Background Art

[0002] Functional neuroimaging is a key technology that can show the metabolic activity of the brain when performing certain tasks (including sensory, motor and cognitive functions), and is often used in medical neuroscience diagnosis and psychology research. Electroencephalogram (EEG) is the most commonly used neurofunctional imaging method. Although EEG has a great advantage in temporal resolution, it is affected by the volume conductor effect of the brain, and the spatial resolution of EEG is relatively low, usually in the order of centimeters. As an emerging imaging technology, electroacoustic imaging is expected to break through the limitations of the volume conductor effect and achieve non-invasive high-temporal and spatial resolution detection of neural electrical activity.

[0003] Acoustoelectric imaging technology is based on the acoustoelectric effect, that is, when ultrasound passes through biological fluids or tissues, it will cause changes in local conductivity (FEFox et al., "The effect of ultrasonic waves on the conductivity of salt solutions," Phys Rev, vol. 70, no. 5-6, pp. 329-339, Sep. 1946.); (Witte RS, Olafsson R, Huang SWI imaging current flow in lobster nerve cord using the acoustoelectric effect [J]. Applied Physics Letters, 2007, 90 (16): 163902.); (Li Q, Olafsson R, Ingram P, et al. Measuring the acoustoelectric interaction constant using ultrasound current source density imaging [J]. Physics in Medicine & Biology, 2012, 57 (19): 5929-5941.). Therefore, at the focal spot formed by focused ultrasound, high-frequency acoustoelectric signals can be generated by the coupling of the electric field and the acoustic field. Focused ultrasound scans a certain brain area (including activated areas and inactivated areas). The activated area modulated by ultrasound outputs high-frequency acoustic and electrical signals, while the inactivated area outputs noise signals. Electrodes are used to collect the output acoustic and electrical signals, and the collected signals are filtered and envelope extracted to complete decoding. The distribution of the source electric field can be decoded from the acoustic and electrical signals at all scanning sites to obtain EEG signals with precise location information, which retains the high temporal resolution advantage of traditional EEG imaging technology while overcoming its insufficient spatial resolution.Based on the acoustoelectric effect, Russell Witte and others have done a lot of work on acoustoelectric imaging technology, (Olafsson R, Witte RS, Huang SW, et al. Ultrasound current source density imaging. IEEE Transactions on Biomedical Engineering, 2008, 55(7): 1840-1848.); (Qin, Y., Ingram, P., Burton, A., et al. 4D acoustoelectric imaging of current sources in a human headphantom. In Ultrasonics Symposium (IUS), 2016 IEEE International (pp. 1-4).) These works verified the modulation and decoding of bioelectric signals by ultrasound, and provided a theoretical basis for the present invention.

[0004] At present, acoustic-electric imaging technology uses point-by-point scanning to scan the detected brain area (including mechanical point-by-point scanning of ultrasonic self-focusing transducers and electronic point-by-point scanning of phased arrays), and images the activation source signals by scanning point by point and decoding them one by one (Xizi S, Xinrui C, Jiande G, et al. Living Rat SSVEP Mapping with Acoustoelectric Brain Imaging. [J]. IEEE transactions on bio-medical engineering, 2021, PP.); (Tianjin University. An acoustic-electric neural imaging system for multi-source activation detection [P]. CN111227801B, 2022-06-10.). However, the point-by-point scanning imaging method will cause the imaging results to be presented in different time spans. In the long-span scanning, relevant important information will inevitably be missed. At the same time, the more sites are scanned, the longer the acquisition and scanning time will be, and the imaging results will inevitably be inaccurate in describing the normal electrophysiological response. On the other hand, there are often multiple activation areas at the same time in the electrical activity of biological brains, and the physiological correlation between activation areas is also an important content in the study of brain activity. Therefore, in clinical applications and research, there is a need for synchronous detection of multi-site activation source signals and research on their conduction networks. Traditional electroacoustic imaging methods have serious limitations, which restricts the scope of application of electroacoustic imaging technology. Summary of the invention

[0005] In view of the above shortcomings of the prior art, the present invention provides a method for acoustic and electrical imaging with synchronous detection of multiple sites. The technical solution of the present invention is as follows:

[0006] A multi-site synchronous detection acoustic and electrical imaging method comprises the following steps:

[0007] 1) Build a multi-focal spot electroacoustic imaging system, including an ultrasound transmission system, an electroencephalographic acquisition system, and an electrical signal processing system;

[0008] 2) Adjust the emission rules of the transducer emitting ultrasound, design the emission mode of the multi-focal spot array element, thereby adjusting the acoustic field characteristics and generating multiple ultrasonic beams; on the basis of the emission mode of the multi-focal spot array element, adopt the emission element amplitude apodization method to reduce the width of the ultrasonic beam and the focal spot size, ensure that there is no overlap and interference between the multiple ultrasonic beams and the focal spots, and the multiple focal spot sites formed respectively encode the electrical signals at the corresponding sites;

[0009] The amplitude apodization method of the transmitting array element is as follows: in order to obtain a smaller focal spot main lobe, a window function is added to the excitation of multiple array elements, so that there are differences between the excitation voltages of the array elements transmitting the same beam, and a smaller weighting coefficient is given to the center array element of the transducer in the transmitting state, while the weighting coefficient of the array element close to the end is gradually increased;

[0010] 3) Design of pulse repetition frequency characteristics: on the basis of the multi-focal spot array element emission mode of the ultrasonic transducer, by changing the interval time of the ultrasonic transducer array element emission pulse, the pulse repetition frequency characteristic setting of the multi-focal spot beam is realized, and multiple focal spot beams with different pulse repetition frequencies are formed, and correspondingly, multiple focal spots with different pulse repetition frequencies are formed, thereby obtaining a multi-beam acoustic field with different pulse repetition frequencies;

[0011] 4) Using the obtained multi-beam acoustic field with different pulse repetition frequencies to scan multiple points in the target area, the beam forms a focal spot at the focal plane, and the multiple focal spots of the acoustic field will respectively encode the electrical signals of the corresponding areas to form coded acoustic and electrical signals;

[0012] 5) Collect the coded acoustic and electrical signals, and filter and decode the collected signals as follows:

[0013] The collected signal is subjected to bandpass filtering centered on the ultrasonic pulse repetition frequency, and the acoustic and electrical signals obtained by filtering are decoded;

[0014] 6) The scanned multiple sites correspond to the focal spots in the area respectively, and filtering and decoding are performed in sequence according to the pulse repetition frequency of the corresponding focal spot beam to obtain the amplitude of the decoded signal of each site;

[0015] 7) The decoded signal amplitudes of all sites are normalized and interpolated to achieve electroacoustic imaging based on multi-region combination and multi-site synchronous detection.

[0016] Furthermore, the transducer adopts a linear array transducer, and the selected window function is:

[0017]

[0018] Where N is the number of array elements corresponding to a beam, i = 1,…,N, W i is the weighting coefficient of the ith array element, α is the adjustment parameter, [α∈(0,0.5)].

[0019] Specifically,

[0020] Furthermore, methods for decoding the acoustic and electrical signals obtained by filtering include a direct envelope method and a Hilbert transform eigenvalue method.

[0021] The beneficial effects of the technical solution provided by the present invention are:

[0022] 1) Increased application scenarios of electroacoustic imaging technology: Under the premise of multiple frequency filtering and decoding, the number of ultrasonic beams and focal spots can be increased, thereby achieving simultaneous detection of a larger range and more sites, breaking through the limitations of scanning detection of traditional electroacoustic imaging technology.

[0023] 2) Shortened data acquisition time: Through simultaneous scanning of multiple sites with multiple focal spots, simultaneous imaging of multiple sites is completed through data processing and other methods, which optimizes the operation of traditional single focal spot scanning of a single point. Compared with traditional acoustic field scanning, it shortens the scanning acquisition time, expands the scanning area, and improves the real-time imaging.

[0024] 3) Expanded development direction: The electroacoustic imaging technology of multi-site synchronous detection can be used to detect multiple brain regions simultaneously, or multi-site activation detection in the same brain region, to obtain imaging results of multiple activated areas inside the brain at the same time, which provides strong support for the synchronous detection of multi-site activation source signals and the research on their conduction networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of pulse repetition frequency characteristics of multi-focal spot acoustic field;

[0026] Figure 2 Figure 2 is a multi-focal sound field diagram. (a) The original multi-focal sound field. (b) The multi-focal sound field after amplitude apodization.

[0027] Figure 3 Based on Figure 2Schematic diagram of the experimental setup for multi-site synchronous detection of multiple focal spot acoustic fields.

[0028] Figure 4 Based on Figure 2 Spectrum diagram of the decoding results of the multi-site synchronous detection electroacoustic imaging experiment with multiple focal spot sound fields.

[0029] Figure 5 Based on Figure 2 Graphic reconstruction of the decoding results of the multi-site synchronous detection of multiple focal spot acoustic fields in the electroacoustic imaging experiment. DETAILED DESCRIPTION

[0030] Firstly, the basic technical solution of the present invention will be described below.

[0031] The acoustoelectric effect is a basic physical phenomenon of ultrasound modulation of electricity, and is also the physical basis of acoustoelectric imaging technology. When focused ultrasound passes through biological fluids or tissues, it causes changes in local (focused area) conductivity. When there is current in this focused area, the local change in resistivity causes current changes, thereby generating current modulation. This process is the acoustoelectric effect.

[0032] Based on the traditional electroacoustic imaging technology, the present invention optimizes the ultrasonic sound field, designs a multi-focal spot sound field through beam synthesis and amplitude apodization technology, and each focal spot beam has different pulse repetition frequency characteristics. In multi-site synchronous detection, the corresponding area of ​​the multi-focal spot beam of the ultrasonic sound field is the multi-site to be detected, and each beam of the sound field will modulate the electrical signal in the corresponding area of ​​the beam to form an electroacoustic signal with the pulse repetition frequency characteristics corresponding to the focal spot beam. With this pulse repetition frequency as the center, the collected electrical signal is band-pass filtered to obtain the electroacoustic signal at each detection site respectively. Finally, the electroacoustic signal is decoded by decoding technology to obtain the electrical signal at each site, thereby realizing electroacoustic imaging of multi-site synchronous detection. The method provided by the present invention realizes the synchronous detection of EEG signals at multiple sites using electroacoustic imaging technology, solves the needs of synchronous detection of multi-site activation source signals and research on their conduction networks, and expands the scope of application of electroacoustic imaging technology. See the following description for details:

[0033] Patent 202011026933.X proposes that the expression for encoding electrical signals into acoustic-electric signals by high-frequency focused ultrasound is:

[0034]

[0035] Among them J I =J I (x,y,z) is a distributed current source, is the lead field of lead i, σ0 is the initial conductivity, K is the acoustic-electric effect coefficient, ΔP is the change in the ultrasonic sound pressure at the corresponding site, (x, y, z) is the coordinate of the site in the rectangular coordinate system of ultrasonic focusing, and f PRF is the pulse repetition frequency, and t is the ultrasonic propagation time.

[0036] The pulse repetition frequency of the ultrasonic beam is one of the important parameters in ultrasound. The design of the pulse repetition frequency characteristics of the ultrasonic beam will directly affect the information of the acoustic and electrical signals. At the same time, considering the existence of multiple detection sites, the changes in ultrasonic sound pressure at different sites will also be different. Therefore, the expression of the acoustic and electrical signals satisfies the following relationship:

[0037]

[0038] Among them, ΔP(x,αy,z,f PRF ,t) is the change of sound pressure at (x,y,z), and (x,y,z) is the coordinate position of the focus spot of the ultrasonic beam. In the method of the present invention, the emission rule of the transducer emitting ultrasound is adjusted, the array element emission mode is designed to adjust the acoustic field characteristics, and multiple beams with different pulse repetition frequencies are generated, thereby forming multiple focus spot sites, which encode the electrical signals at the corresponding sites respectively. The ΔP (x,y,z,f) of each focus spot position is PRF ,t) is also affected by the coordinate position, and the beam pulse repetition frequency characteristics corresponding to each focal spot are also different. Therefore, the encoded multi-site high-frequency acoustic and electrical signals satisfy the following relationship:

[0039]

[0040] Where n is the number of beams in the multi-focal acoustic field, and also the number of focal spots in beamforming (n ≥ 2 and n is an integer), represents the pulse repetition frequency of the kth beam among the n different pulse repetition frequency beams of the transducer, (x k ,y k ,z k ) is the specific position of the kth beam focusing point.

[0041] In the method of the present invention, the technical core is to design the ultrasonic emission mode of the transducer to obtain a multi-beam sound field with different pulse repetition frequencies. When the excitation amplitudes given by each array element are the same, the equal-amplitude coherent superposition of the sound beam will concentrate the energy mainly on the main lobe. If the main lobe size is too large, there will be overlap between the focal spots, which will cause negative interference to the high-precision detection of the acoustic and electrical signals. Therefore, in order to obtain a smaller focal spot main lobe, on the basis of the traditional ultrasonic transducer focusing technology, a window function is added to the array element excitation so that the excitation voltage of each array element is different. Unlike the traditional continuous wave amplitude apodization technology, the method of the present invention assigns a smaller weighting coefficient to the center array element of the transducer in the transmitting state, and gradually increases the weighting coefficient of the array element close to the end. Taking the linear array transducer as an example, further function design is performed on the basis of the common window function:

[0042]

[0043] Wherein, in the multi-beam acoustic field of the transducer, N is the number of array elements corresponding to one ultrasonic beam, i=1,…,N,W i is the weighting coefficient of the ith array element. Based on the weighted amplitude apodization of the array element, the acoustic beam is formed by delayed focusing, which reduces the size of the focal spot main lobe and obtains a narrower ultrasonic beam, thereby ensuring that the focal spot beams do not interfere with each other.

[0044] The present invention is described below in conjunction with embodiments.

[0045] Example 1

[0046] The multi-site synchronous detection acoustic and electrical imaging method of the present invention specifically comprises the following steps:

[0047] 1) Build a multi-focal spot electroacoustic imaging system, including an ultrasound transmission system, an electroencephalographic acquisition system, and an electrical signal processing system.

[0048] 2) Design of ultrasonic emission mode: By setting up an ultrasonic drive device, the array elements of the ultrasonic transducer are divided and combined to achieve simultaneous emission of multiple focal spot beams and form a multi-focal spot sound field. On the basis of the multi-focal spot emission mode, the amplitude apodization of the emission array element is adopted to reduce the width of the ultrasonic beam and the focal spot size, ensuring that there is no overlap and interference between multiple sound beams and focal spots.

[0049] 3) Design of pulse repetition frequency characteristics: Based on the combination of ultrasonic transducer array elements, the pulse repetition frequency characteristics of the multi-focal spot beam are set by changing the interval time of the ultrasonic transducer array element transmitting pulses, so as to form multiple focal spot beams with different pulse repetition frequencies, and correspondingly form multiple focal spots with different pulse repetition frequencies, such as Figure 1 shown.

[0050] 4) Under the set experimental paradigm, a multi-focal spot sound field is used to scan multiple locations in the target area, wherein the sound field is a plurality of ultrasonic beam sound fields designed with emission mode and pulse repetition frequency characteristics as mentioned above, and the beam forms a focal spot at the focal plane. The multiple focal spots of the sound field will respectively encode the electrical signals of the corresponding areas to form coded acoustic and electrical signals.

[0051] 5) Collect the encoded signal, which includes the acoustic and electrical signals after each ultrasonic beam encodes the electrical signal separately, as shown in formula (3). Filter and decode the collected signal. First, the collected electrical signal is subjected to bandpass filtering centered on the ultrasonic pulse repetition frequency, and then the filtered acoustic and electrical signal is decoded. The decoding methods include the direct envelope method and the Hilbert transform eigenvalue method. The scanned multiple sites correspond to the focal spots in the area respectively. They are filtered and decoded in turn according to the pulse repetition frequency of the corresponding focal spot beam, and the passband filter center of the bandpass filter is set to By frequency The encoded acoustic and electrical signals will be filtered out by the filter, leaving only the The sound and electricity signal of frequency is decoded according to this frequency, and (x k ,y k ,z k ) point.

[0052] 6) Repeat the operation of step 5, select the parameters of bandpass filtering according to the pulse repetition frequency of other ultrasonic beams, perform filtering and decoding respectively, and obtain all sites ((x k ,y k ,z k ), k∈[1,n]), and finally the amplitudes of all scanning points are normalized and interpolated to realize multi-region combined acoustic and electrical imaging, and realize synchronous detection of multiple points in the region, which is also the key part involved in the present invention.

[0053] To summarize, the embodiment of the present invention implements an electroacoustic imaging method of multi-site synchronous detection through the above steps, and realizes the synchronous detection of multi-site signals. Compared with the traditional electroacoustic imaging technology, the multi-site synchronous detection method solves the problem of multi-site synchronous detection in the traditional technology by increasing the number of focal spots, and multiple focal spots have different pulse repetition frequencies, thus breaking through the limitations of the traditional electroacoustic imaging technology.

[0054] Example 2

[0055] In the multi-site acoustic and electrical imaging method proposed in the present invention, the principle and method of multi-site detection of double focal spots, three focal spots, four focal spots and more focal spots are the same. Figure 2 , Figure 3 and Figure 4 , the scheme in Example 1 is further described using the acoustic field of four focal spots and four activation source signals. The synchronous detection of multiple sites is achieved by the ultrasonic acoustic field of multiple focal spots, as described below:

[0056] The ultrasonic transmitting system, the EEG acquisition system and the signal processing system are installed and connected to assemble a multi-focal spot electroacoustic imaging system, wherein the ultrasonic transmitting device includes an ultrasonic driving device and an ultrasonic transducer.

[0057] This embodiment is based on the Verasonics ultrasonic transmitting system, and uses the L11-5v model (7.6MHz, 128 array elements, linear array) phased array ultrasonic transducer for array element control. The 128 array elements are divided into four adjacent 32 array element groups, where each 32 array element group forms a beam through a time delay algorithm, and a total of four ultrasonic beams are obtained, corresponding to four ultrasonic focusing focal spots, and the sound field is obtained as follows: Figure 2 (a) As shown in the figure.

[0058] The acoustic field amplitude apodization technology designed by the method of the present invention is shown in formula (4). The transmission excitation of four 32 array element groups is adjusted. A relatively small voltage excitation is given to the middle array element, while the voltage excitation of the array elements at both ends is increased, so that the energy of the ultrasonic beam is more concentrated, the focal spot formed is smaller, and there is no overlap and interference between the focal spots. The sound field after processing is as follows: Figure 2 (b) As shown in the figure.

[0059] Figure 2 (a)(b) Four focal spot sound field diagrams, the upper part is a three-dimensional diagram, and the lower part is a focal plane diagram); in the figure, the focal length and focusing mode of the four focal spots are the same, so the sound fields of the four focal spots are basically the same. The ultrasonic sound field is designed, that is, the emission rule of the transducer array element that controls the ultrasound is adjusted, and the amplitude apodization function of the emission array element is introduced, so as to reduce the width of the ultrasonic beam and reduce the focal spot size.

[0060] The pulse repetition frequency of the ultrasonic beam is controlled by individually setting the time interval of each ultrasonic beam pulse emission to ensure that the pulse repetition frequencies of the four focal spot beams are different. In this embodiment, the pulse repetition frequencies are set to PRF1: 180 Hz, PRF2: 260 Hz, PRF3: 340 Hz, and PRF4: 420 Hz.

[0061] In specific implementation, other ultrasonic transmitting systems and types of ultrasonic transducers may also be used, and the frequency setting may also be modified according to the specific source signal, which is not limited in the embodiment of the present invention.

[0062] The three-dimensional motion controller is used to control the ultrasonic transducer to scan multiple points in the target area. The scanning diagram is shown in the figure. Figure 3 As shown, the area to be detected is a rectangular area of ​​8mm×22mm, wherein there are four activation sources (S1: 9Hz, S2: 13Hz, S3: 17Hz, S4: 21Hz), which are respectively located at (-8, 0), (-2, 0), (4, 0) and (10, 0) positions on the X-axis (Y=0), and the relative positions of the four focal spots are controlled to be the same as the relative positions of the activation sources. During the scanning process, the ultrasonic transducer moves in steps of 2mm each time, so there are 60 sites to be scanned in the corresponding area to be detected. The traditional point-by-point scanning acoustic and electrical imaging technology requires encoding and decoding of all sites in sequence, and the time utilization is low. In the method of the present invention, multi-beams with different pulse repetition frequencies are introduced to improve the scanning efficiency. The four beams are simultaneously scanned with equal steps. Only 15 sites need to be scanned to complete the synchronous encoding of 60 sites in the entire area. Signal acquisition can obtain an electrical signal containing four pulse repetition frequency information and four activation source frequency information.

[0063] The collected electrical signal is bandpass filtered, and the filter passband center is the pulse repetition frequency, and the acoustic and electrical signal corresponding to this frequency is obtained. Since there are four beam pulse repetition frequencies, bandpass filtering is performed with the filter bandwidth of the four centers respectively, and the acoustic and electrical signals corresponding to the pulse repetition frequencies of different beams can be obtained, and the acoustic and electrical signals are envelope decoded to obtain the acoustic and electrical signal amplitude. The above-mentioned multi-passband filtering process is performed on the collected 15 scanning site signals one by one to obtain the amplitude of each site in the area corresponding to the beam pulse repetition frequency (for example, using PRF1 (f1) as the filter center for filtering and decoding, the decoding results of each site in area 1 including the activation source S1 corresponding to beam 1 can be obtained), and finally normalization is performed to decode the acoustic and electrical imaging result diagram of this area, thereby obtaining the electric field distribution of the source signal.

[0064] The decoding result is as follows Figure 4 As shown in the figure, the decoding conditions at 12 sites on the X-axis (Y=0) correspond to the same positions in different regions (all are the activation source positions and the positions 2mm on both sides of the activation source), and different passbands are used for filtering. Obvious amplitude information is decoded at X=-8, -2, 4 and 10, among which 9Hz information corresponding to activation source S1 is decoded at X=-8, 13Hz information corresponding to activation source S2 is decoded at X=-2, 17Hz information corresponding to activation source S3 is decoded at X=4, and 21Hz information corresponding to activation source S4 is decoded at X=10, while no obvious results are decoded at the remaining sites on the same line.

[0065] like Figure 5As shown in the figure, each regional site is decoded based on the pulse repetition frequency f1-f4, and the regional imaging corresponding to a single beam is completed. The four independent filtering and decoding results are integrated to obtain the decoding signal amplitude of all scanning sites, and then the acoustic and electrical signal decoding amplitude is used to complete the graphic reconstruction to obtain the final decoding signal distribution diagram. By comparing with the source signal distribution, the decoding imaging result is basically consistent with the electric field distribution of the original four activation source signals.

[0066] In summary, the multi-site synchronous detection electroacoustic imaging method provided by the present invention can realize the demand for synchronous detection of signals at multiple sites. The invention can be used in clinical medical diagnosis, cerebrovascular disease rehabilitation, neuroengineering and other fields. Further research can obtain more perfect electroacoustic neuroimaging technology, and even obtain a real-time high spatial resolution neural signal detection method, which is expected to obtain considerable social and economic benefits.

[0067] Unless otherwise specified, the models of the components in the embodiments of the present invention are not limited, and any device that can perform the above functions may be used.

[0068] Those skilled in the art will appreciate that the accompanying drawing is only a schematic diagram of a preferred embodiment, and the serial numbers of the embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for acoustic and electrical imaging of multi-site synchronous detection, comprising the following steps: 1) Build a multi-focal spot acoustic and electrical imaging system, including an ultrasound transmission system, an electroencephalogram acquisition system, and an electrical signal processing system; 2) Adjust the emission rules of the transducer emitting ultrasound, design the emission mode of the multi-focal spot array element, thereby adjusting the acoustic field characteristics and generating multiple ultrasonic beams; on the basis of the emission mode of the multi-focal spot array element, adopt the emission element amplitude apodization method to reduce the width of the ultrasonic beam and the focal spot size, ensure that there is no overlap and interference between the multiple ultrasonic beams and the focal spots, and the multiple focal spot sites formed respectively encode the electrical signals at the corresponding sites; in, The transmit array element amplitude apodization method is as follows: in order to obtain a smaller focal spot main lobe, a window function is added to the multi-element excitation, so that there is a difference between the excitation voltages of the array elements emitting the same beam, and a smaller weighting coefficient is given to the center element of the transducer in the transmitting state, while the weighting coefficient of the array element close to the end is gradually increased; 3) Design of pulse repetition frequency characteristics: on the basis of the multi-focal spot array element emission mode of the ultrasonic transducer, by changing the interval time of the ultrasonic transducer array element emission pulse, the pulse repetition frequency characteristic setting of the multi-focal spot beam is realized, and multiple focal spot beams with different pulse repetition frequencies are formed, and correspondingly, multiple focal spots with different pulse repetition frequencies are formed, thereby obtaining a multi-beam acoustic field with different pulse repetition frequencies; 4) Using the obtained multi-beam acoustic field with different pulse repetition frequencies to scan multiple points in the target area, the beam forms a focal spot at the focal plane, and the multiple focal spots of the acoustic field will respectively encode the electrical signals of the corresponding areas to form coded acoustic and electrical signals; 5) Collect the coded acoustic and electrical signals, and filter and decode the collected signals as follows: The collected signal is subjected to bandpass filtering processing centered on the ultrasonic pulse repetition frequency, and the acoustic and electrical signals obtained by filtering are decoded; 6) The scanned multiple sites correspond to the focal spots in the area respectively, and filtering and decoding are performed in sequence according to the pulse repetition frequency of the corresponding focal spot beam to obtain the decoded signal amplitude of each site; 7) The decoded signal amplitudes of all sites are normalized and interpolated to achieve electroacoustic imaging based on multi-region combination and multi-site synchronous detection.

2. The method for acoustic and electrical imaging of multi-site synchronous detection according to claim 1, characterized in that: The transducer adopts a linear array transducer, and the selected window function is: Where N is the number of array elements corresponding to a beam, i = 1,…,N, W i is the weighting coefficient of the ith array element, α is the adjustment parameter, [α∈(0,0.5)].

3. The method for acoustic and electrical imaging of multi-site synchronous detection according to claim 1, characterized in that:

4. The method for acoustic and electrical imaging of multi-site synchronous detection according to claim 1, characterized in that: Methods for decoding the acoustic and electrical signals obtained by filtering include a direct envelope method and a Hilbert transform eigenvalue method.

Images