Transcranial ultrasound visual stimulation closed-loop system

Abstract

The application discloses a transcranial ultrasound visual stimulation closed-loop system. The system comprises a driving control module, an imaging processing module and a feedback correction module. The driving control module is used for determining driving parameters of each target stimulation point on the visual cortex according to image data. The imaging processing module is used for emitting a detection ultrasound before emitting a stimulation pulse and determining an initial position of a target region; the driving control module pre-corrects the driving parameters according to a deviation between the initial position and an expected position and emits the stimulation pulse; the imaging processing module is also used for emitting an imaging ultrasound after stimulation and reconstructing a functional ultrasound image. The feedback correction module is used for determining an actual activation position according to the functional ultrasound image, comparing the actual activation position with the expected position, and correcting phase delays of each array element to adjust a subsequent focusing position if a deviation exceeds a preset threshold. The transcranial ultrasound visual stimulation closed-loop system of the application realizes automatic correction of a focusing position of transcranial ultrasound visual stimulation through closed-loop control.

Description

Technical Field

[0001] This application relates to the field of ultrasound visual stimulation technology, and more specifically, to a transcranial ultrasound visual stimulation closed-loop system. Background Technology

[0002] Transcranial focused ultrasound (TUS), as a non-invasive neuromodulation technique, can penetrate the skull to stimulate deep brain tissue, showing great promise for applications in visual reconstruction. Existing research indicates that TUS stimulation of the primary visual cortex can induce cortical activation responses, with the activation area spatially overlapping with the ultrasound stimulation area. However, current known TUS visual stimulation protocols all employ an open-loop control mode. After the system emits ultrasound waves according to pre-calculated driving parameters, it cannot determine whether the stimulation accurately reaches the target cortical region or whether the target neurons are effectively activated. This open-loop mode has the following inherent drawbacks: First, brain tissue undergoes periodic micro-displacements with heartbeat and respiration, which the pre-calculated phase model cannot compensate for, leading to a deviation between the actual stimulation location and the target location. Second, individualized acoustic models constructed based on CT or MRI image data have segmentation and parameter assignment errors, which the open-loop system cannot correct. Third, the open-loop system cannot confirm whether the target neurons have been successfully activated after emitting ultrasound waves, which is particularly disadvantageous for completely blind users, as the system cannot adjust parameters based on the stimulation effect.

[0003] Functional ultrasound (FUS) imaging technology has developed rapidly in recent years. Based on ultrafast plane wave acquisition, FUS can indirectly reflect neuronal activity by detecting changes in cerebral blood flow caused by neurovascular coupling, offering high spatiotemporal resolution and a large imaging depth. FUS and transcranial focused ultrasound (TCUS) have natural physical compatibility, sharing ultrasound as their physical basis, making it possible to integrate stimulation and imaging functions on the same ultrasound array. However, current technologies do not address the integration of visual cortex topological mapping with FUS imaging feedback, nor do they solve the closed-loop optimization problem of image pixel-to-cortical stimulation for the specific application scenario of visual reconstruction. Summary of the Invention

[0004] One objective of this application is to provide a transcranial ultrasound visual stimulation closed-loop system that can at least solve the above-mentioned technical problems in the prior art.

[0005] To achieve the above objectives, this application provides the following technical solutions.

[0006] A transcranial ultrasound visual stimulation closed-loop system according to an embodiment of this application includes: a drive control module, configured to determine drive parameters for each target stimulation point on the visual cortex based on image data corresponding to the acquired target image; an imaging processing module, configured to control the phased-array ultrasound array to emit a probe ultrasound pulse sequence towards the visual cortex before the drive control module controls the phased-array ultrasound array to emit a first ultrasound pulse sequence, receive the echo signal of the probe ultrasound pulse sequence, and determine the initial position of the target region in the visual cortex based on the echo signal; the drive control module is further configured to pre-correct the drive parameters of the first ultrasound pulse sequence based on the deviation between the initial position and the expected position of the target stimulation point, and control... A phased-array ultrasound array emits a first ultrasound pulse sequence to the visual cortex for focused ultrasound stimulation. The imaging processing module is further configured to control the phased-array ultrasound array to emit an imaging ultrasound pulse sequence to the visual cortex within a first predetermined time window after the first ultrasound pulse sequence is emitted, receive the echo signal of the imaging ultrasound pulse sequence, and reconstruct a functional ultrasound image of the target region of the visual cortex based on the echo signal. A feedback correction module is configured to determine the actual activation position of the target region of the visual cortex based on the functional ultrasound image, compare the actual activation position with the expected position of the target stimulation point, and if the deviation exceeds a preset threshold, correct the phase delay of each array element to adjust the focusing position of the next emitted first ultrasound pulse sequence. The imaging ultrasound pulse sequence is a plane wave ultrasound pulse sequence. Reconstructing the functional ultrasound image of the target region of the visual cortex based on the echo signal includes: the imaging processing module performing beamforming processing on the echo signal to generate an ultrafast ultrasound image sequence of the target region, and performing power Doppler imaging processing on the ultrafast ultrasound image sequence to generate a cerebral blood flow change map of the target region, which serves as the functional ultrasound image.

[0007] Optionally, determining the initial position of the target region in the visual cortex based on the echo signal includes: the imaging processing module performing pulse-echo correlation calculation on the echo signal of the probe ultrasound pulse sequence to obtain the initial displacement of the target region along the direction of each array element's acoustic beam, and determining the initial three-dimensional spatial coordinates of the target region based on the initial displacement.

[0008] Optionally, the system also includes an electrocardiogram (ECG) signal acquisition module for acquiring the user's ECG signal; the drive control module determines the phase of the cardiac cycle based on the R-wave trigger time of the ECG signal, and controls the phased-array ultrasound array to transmit the first ultrasound pulse sequence within the phase window where the brain tissue displacement velocity is the minimum during the cardiac cycle.

[0009] Optionally, the phase delay of each array element is corrected by: the feedback correction module determining the phase compensation amount of each array element based on the spatial deviation between the actual activation position and the expected position, and superimposing the phase compensation amount onto the driving phase of each array element.

[0010] Optionally, the feedback correction module also determines the correction amount of the visual topology mapping model based on the spatial deviation amount, and updates the visual topology mapping model based on the correction amount to correct the mapping relationship between the pixel coordinates and cortical coordinates corresponding to the target stimulus point.

[0011] Optionally, the feedback correction module also determines the activation intensity of the actual activation location based on the functional ultrasound image, compares the activation intensity with the preset target intensity, and adjusts the sound pressure amplitude parameter of the first ultrasound pulse sequence based on the comparison result.

[0012] Optionally, the feedback correction module keeps the current driving parameters unchanged when the deviation is less than or equal to a preset threshold, and triggers correction and records the correction log when the deviation exceeds the preset threshold.

[0013] Optionally, the imaging processing module is also used to monitor the echo signal of the target area in real time during the process of the phased ultrasound array being controlled by the drive control module to emit the first ultrasound pulse sequence for focused ultrasound stimulation, and to determine whether the focusing position of the first ultrasound pulse sequence deviates from the expected position of the target stimulation point based on the echo signal.

[0014] In summary, compared with traditional technologies, the transcranial ultrasound visual stimulation closed-loop system of this application has several beneficial effects: Regarding focusing accuracy, by detecting and pre-correcting micro-displacements of brain tissue before emission, dynamic focusing errors caused by heartbeat and respiration are eliminated. Regarding stimulation effectiveness, the stimulation effect is directly verified through functional ultrasound imaging, and the driving parameters are automatically corrected based on the feedback results, solving the problem that open-loop systems cannot confirm the stimulation effect. Regarding long-term stability, through self-calibration of the visual topology mapping model based on functional ultrasound imaging feedback, the system continuously optimizes during use, overcoming individual differences and model errors. Regarding safety, by monitoring the echo signal in real time during stimulation, focusing shifts can be detected and corrections triggered in a timely manner, providing proactive safety assurance.

[0015] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0017] Figure 1 This is a schematic diagram of the structure of a transcranial ultrasound visual stimulation closed-loop system according to an embodiment of this application; Figure 2 This is a schematic diagram of the workflow of a transcranial ultrasound visual stimulation closed-loop system according to another embodiment of this application. Detailed Implementation

[0018] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0019] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0020] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0021] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0023] System Hardware Architecture

[0024] The transcranial ultrasound visual stimulation closed-loop system provided in this application can be deployed within a complete transcranial ultrasound visual reconstruction hardware system. This system adds an imaging feedback channel to the aforementioned open-loop transcranial ultrasound visual stimulation image encoding system. This transcranial ultrasound visual reconstruction hardware system may include multiple hardware devices such as an image acquisition device, an image processing unit, a phased-array ultrasound stimulation device, a drive circuit, a power supply module, and an external programmer. The phased-array ultrasound device adopts a head-mounted structure, fixed to the user's occipital region, and includes multiple ultrasound transducer elements arranged in a ring on the inside of the helmet; exemplarily, it may include 128 elements. The operating center frequency range of each element can be set from 0.5MHz to 1.5MHz. Unlike conventional open-loop systems, the drive circuit of this application, in addition to outputting high-power stimulation pulses, can also emit low-power plane wave probe pulses and imaging pulses, and receive echo signals for imaging processing. Imaging processing can be implemented using a field-programmable gate array or a high-performance digital signal processor to perform steps such as ultrafast beamforming, power Doppler imaging, and blood flow signal analysis. The power supply module can provide power to multiple hardware modules of this system, and has a built-in rechargeable battery pack. Based on the above hardware, the system of this application is implemented through the following specific embodiments, which will be described in detail below. System Implementation Example: The following is in conjunction with the appendix Figure 1 To be continued Figure 2A specific description of a transcranial ultrasound visual stimulation closed-loop system according to an embodiment of this application.

[0025] In one embodiment of this application, a transcranial ultrasound visual stimulation closed-loop system is provided, comprising: a drive control module, configured to determine drive parameters for each target stimulation point on the visual cortex based on image data corresponding to the acquired target image; an imaging processing module, configured to control the phased-array ultrasound array to emit a probe ultrasound pulse sequence toward the visual cortex before the drive control module controls the phased-array ultrasound array to emit a first ultrasound pulse sequence, receive the echo signal of the probe ultrasound pulse sequence, and determine the initial position of the target region in the visual cortex based on the echo signal; the drive control module is further configured to pre-correct the drive parameters of the first ultrasound pulse sequence based on the deviation between the initial position and the expected position of the target stimulation point, and The system controls a phased-array ultrasound array to emit a first ultrasound pulse sequence toward the visual cortex for focused ultrasound stimulation. The imaging processing module is also used to control the phased-array ultrasound array to emit an imaging ultrasound pulse sequence toward the visual cortex within a first predetermined time window after the first ultrasound pulse sequence is emitted, receive the echo signal of the imaging ultrasound pulse sequence, and reconstruct a functional ultrasound image of the target region of the visual cortex based on the echo signal. The feedback correction module is used to determine the actual activation position of the target region of the visual cortex based on the functional ultrasound image, compare the actual activation position with the expected position of the target stimulation point, and if the deviation exceeds a preset threshold, correct the phase delay of each array element to adjust the focusing position of the next emitted first ultrasound pulse sequence.

[0026] Specifically, in this embodiment, the target image is captured by the aforementioned image acquisition device, generating corresponding image data and transmitting it to the drive control module of this system. Based on the image data, the drive control module determines the spatial position of each target stimulation point on the visual cortex according to a predetermined visual topology mapping model, and calculates the drive parameters corresponding to each element in the phased array ultrasound array. The drive parameters include the drive phase and amplitude values ​​of each element. The specific method for generating these drive parameters can adopt the technical solution described in the prior art CN202611242674.1, which is not the focus of this application and will not be repeated here. Based on this, in this embodiment, before the drive control module controls the phased array ultrasound array to emit stimulation pulses, the imaging processing module first controls the phased array ultrasound array to emit a low-power probe ultrasound pulse sequence towards the visual cortex. The power of this probe ultrasound pulse sequence is much lower than that of the stimulation pulse, and it will not produce a stimulating effect on brain tissue; it is only used for imaging localization. Then, the imaging processing module receives the echo signal of the probe ultrasound pulse sequence and determines the initial position of the target region in the visual cortex at the current moment based on the target region tissue interface information contained in the echo signal. Next, the drive control module calculates the required phase compensation for each array element based on the deviation between the initial position and the expected set position of the target stimulation point, and pre-calibrates the drive parameters of the first ultrasound pulse sequence. After pre-calibration, the drive control module controls the phased array ultrasound array to emit the first ultrasound pulse sequence towards the visual cortex for focused ultrasound stimulation. Specifically, the first ultrasound pulse sequence can be a high-power focused ultrasound pulse, with its sound pressure amplitude set according to the salience level of the target region. Within a first predetermined time window after the first ultrasound pulse sequence is emitted, the imaging processing module again controls the phased array ultrasound array to emit an imaging ultrasound pulse sequence towards the visual cortex, then receives the echo signal of the imaging ultrasound pulse sequence, and reconstructs the functional ultrasound image of the target region of the visual cortex based on the echo signal. It is important to note that the first predetermined time window is specifically the period between 100 ms and 500 ms after the first ultrasound pulse sequence is emitted. Neurovascular coupling refers to the phenomenon that local cerebral blood flow increases after neurons are activated; this phenomenon is the physiological basis of functional ultrasound imaging. After neurons are activated, local cerebral blood flow typically reaches its peak between 100 ms and 500 ms after stimulation. Therefore, setting the transmission time of the imaging ultrasound pulse sequence between 100 and 500 milliseconds after the first ultrasound pulse sequence ensures that imaging is performed when the cerebral blood flow response reaches its peak, thereby obtaining the strongest functional ultrasound signal. The cerebral blood flow change map reflects the local blood flow changes in the target area caused by the neurovascular coupling effect under the stimulation of the first ultrasound pulse sequence. That is, the effectively activated neuronal areas appear as high-signal areas on the functional ultrasound image, while the unactivated areas appear as low-signal areas.

[0027] Based on the above, the feedback correction module in this embodiment determines the actual activation location of the target region in the visual cortex according to the functional ultrasound image and compares the actual activation location with the expected location of the target stimulus point. If the deviation between the two exceeds a preset threshold, the feedback correction module corrects the phase delay of each array element to adjust the focusing position of the first ultrasound pulse sequence emitted in the next iteration. Through this method, the system completes a full closed-loop process from detection and localization, pre-correction, stimulus emission to imaging feedback and phase correction. This will be described in detail below and will not be elaborated upon here.

[0028] Furthermore, in this embodiment, the imaging ultrasound pulse sequence can employ a plane wave transmission method. Specifically, in this embodiment, all elements of the phased-array ultrasound system simultaneously transmit plane waves, covering the entire imaging field of view in a single transmission, eliminating the need for line-by-line scanning and significantly improving the imaging frame rate. The advantage of using a plane wave transmission method here is that traditional focused imaging requires transmitting and receiving scan lines one by one, limiting the frame rate to the number of scan lines; while plane wave transmission only requires a single transmission to obtain echo data for the entire field of view, increasing the frame rate to the kilohertz level. This high frame rate provides sufficient temporal sampling density for subsequent power Doppler imaging, facilitating the detection of slow blood flow changes.

[0029] Furthermore, in this embodiment, the aforementioned functional ultrasound image reconstructing the target region of the visual cortex based on echo signals further includes: an imaging processing module performing beamforming processing on the echo signals to generate an ultrafast ultrasound image sequence of the target region, and performing power Doppler imaging processing on the ultrafast ultrasound image sequence to generate a cerebral blood flow change map of the target region, which serves as the functional ultrasound image. Specifically, in this embodiment, after receiving the echo signal emitted by the plane wave, the imaging processing module first performs time-delay summation beamforming on the echo signals received by each array element. In other words, the imaging processing module calculates the time delay based on the geometric distance between each array element and the imaging point, and then superimposes the signals from each array element after time-delay alignment to reconstruct the ultrasound image of the target region. The high frame rate of ultrafast imaging enables power Doppler imaging to detect subtle changes in slow blood flow. The specific implementation of power Doppler imaging processing involves performing Doppler processing on the pixel values ​​at the same spatial location at different times in the ultrafast ultrasound image sequence to extract the Doppler signal energy from moving scatterers (e.g., flowing red blood cells). The intensity of the power Doppler signal is proportional to the number of red blood cells per unit volume, reflecting cerebral blood flow at that location. The advantage of this approach is that, through the above processing, the imaging module generates a map of cerebral blood flow changes in the target region, serving as a functional ultrasound image.

[0030] In some embodiments of this application, determining the initial position of the visual cortex target region based on the echo signal includes: the imaging processing module performing pulse-echo correlation calculation on the echo signal of the probe ultrasound pulse sequence to obtain the initial displacement of the target region along the direction of each element's acoustic beam, and determining the initial three-dimensional spatial coordinates of the target region based on the initial displacement.

[0031] Specifically, in this embodiment, the imaging processing module performs pulse-echo correlation calculations on the echo signals of the probed ultrasound pulse sequence to obtain the initial displacement of the target region along the acoustic beam direction of each array element. The specific method for pulse-echo correlation calculation is as follows: the imaging processing module performs cross-correlation operations between the echo signal of the current frame's probe pulse and the corresponding echo signal of the previous frame or reference frame to calculate the time shift between the two frames. The time shift is calculated based on the relationship between signal time offset and tissue displacement; that is, when the target tissue displaces along the acoustic beam direction, the echo signal shifts accordingly on the time axis, and the offset is proportional to the displacement. This time shift reflects the displacement of the target tissue along the acoustic beam direction. Since the displacement components of the target region differ in the acoustic beam direction of different array elements, the imaging processing module integrates the displacement components measured by multiple array elements and reconstructs the initial three-dimensional spatial coordinates of the target region through triangulation or iterative optimization algorithms. The advantage of this approach is that, through this method, the system can obtain the actual position of the target region in three-dimensional space in real time with micron-level accuracy, providing precise displacement data for subsequent pre-correction.

[0032] In some other embodiments of this application, the system further includes an electrocardiogram (ECG) signal acquisition module for acquiring the user's ECG signal; and a drive control module for determining the cardiac cycle phase based on the R-wave triggering time of the ECG signal, and controlling the phased-array ultrasound array to transmit a first ultrasound pulse sequence within the phase window where the brain tissue displacement velocity is minimum during the cardiac cycle.

[0033] Specifically, in this embodiment, the system further includes an electrocardiogram (ECG) signal acquisition module for acquiring the user's ECG signal. The ECG signal acquisition module can use surface electrodes attached to the user's chest to acquire ECG signals in real time and extract the R-wave trigger moment. The R-wave is the most prominent waveform on an ECG, representing the instant the ventricles begin to contract. The drive control module determines the phase position of the current cardiac cycle based on the R-wave trigger moment of the ECG signal. During the systolic phase of the cardiac cycle, brain tissue undergoes rapid displacement with arterial pulsation; while at the end of diastole, the brain tissue displacement speed is slowest and the position is most stable. The drive control module controls the phased-array ultrasound array to emit the first ultrasound pulse sequence within the phase window of the cardiac cycle when the brain tissue displacement speed is minimal, thereby temporally avoiding the peak period of brain tissue pulsation.

[0034] In another embodiment of this application, correcting the phase delay of each array element includes: the feedback correction module determines the phase compensation amount of each array element based on the spatial deviation between the actual activation position and the expected position, and superimposes the phase compensation amount onto the driving phase of each array element.

[0035] Specifically, in this embodiment, the feedback correction module determines the phase compensation amount for each array element based on the spatial deviation between the actual activation position and the expected position. Simply put, the spatial deviation is a three-dimensional vector containing deviation components in three orthogonal directions. The feedback correction module projects this three-dimensional deviation vector onto the sound beam direction from each array element to the target point and calculates the required phase compensation amount for each element. The formula for calculating the phase compensation amount is: the phase compensation amount equals the angular frequency multiplied by the projected component of the deviation in the sound beam direction divided by the speed of sound. Then, the feedback correction module superimposes the phase compensation amount of each array element onto the current driving phase of each element. After superposition, the interference mode of the ultrasonic waves emitted by each array element in space changes, causing the focusing position of the next stimulus to converge towards the actual activation position.

[0036] In some embodiments of this application, the feedback correction module further determines the correction amount of the visual topology mapping model based on the spatial deviation amount, and updates the visual topology mapping model based on the correction amount to correct the mapping relationship between the pixel coordinates and cortical coordinates corresponding to the target stimulus point.

[0037] Specifically, in this embodiment, the feedback correction module further determines the correction amount of the visual topology mapping model based on the spatial deviation. The visual topology mapping model establishes a correspondence between image pixel coordinates and visual cortical coordinates, that is, each image pixel is mapped to a coordinate point on the cortex. When there is a spatial deviation between the actual activation position and the expected position, it indicates that there is an error in the mapping relationship. The feedback correction module uses this spatial deviation as the correction amount of the mapping model and updates the mapping relationship corresponding to the target stimulus point in the visual topology mapping model according to the correction amount. The specific update method is: the cortical coordinates corresponding to the stimulus block in the mapping relationship are shifted from the original expected position to the actual activation position by a portion of the deviation amount to avoid overcorrection caused by noise in a single measurement.

[0038] In one embodiment of this application, the feedback correction module further determines the activation intensity of the actual activation location based on the functional ultrasound image, compares the activation intensity with the preset target intensity, and adjusts the sound pressure amplitude parameter of the first ultrasound pulse sequence based on the comparison result.

[0039] Specifically, in this embodiment, the feedback correction module further determines the activation intensity of the actual activation location based on the functional ultrasound image. Activation intensity refers to the percentage increase in blood flow signal in the actual activated area of ​​the functional ultrasound image relative to the baseline. After a neuron is activated, local cerebral blood flow increases, and the signal intensity of the functional ultrasound image increases accordingly. The magnitude of the signal increase is related to the intensity of neuronal activity. The feedback correction module compares the measured activation intensity with a preset target intensity. If the activation intensity is lower than the target intensity, it indicates that the current stimulation intensity is insufficient to fully activate the target neuron, and the feedback correction module appropriately increases the sound pressure amplitude parameter of the first ultrasound pulse sequence corresponding to that area; if the activation intensity is higher than the target intensity, the sound pressure amplitude parameter is appropriately decreased, thereby minimizing ultrasound energy exposure while ensuring effective activation.

[0040] In one embodiment of this application, the feedback correction module keeps the current driving parameters unchanged when the deviation is less than or equal to a preset threshold, and triggers correction and records the correction log when the deviation exceeds the preset threshold.

[0041] Specifically, in this embodiment, the feedback correction module keeps the current driving parameters unchanged when the deviation is less than or equal to a preset threshold, and triggers correction and records the correction log when the deviation exceeds the preset threshold. The preset threshold is exemplarily set to 0.3 mm. When the spatial deviation between the actual activation position and the expected position is less than or equal to 0.3 mm, the system assumes that the current focusing accuracy meets the requirements and no correction is needed, thus saving computational resources and avoiding unnecessary phase adjustments that introduce additional errors. When the deviation exceeds 0.3 mm, the system triggers the correction process, that is, the feedback correction module calculates the phase compensation amount and updates the driving parameters in the aforementioned manner, while recording the relevant information of this correction in the correction log. The correction log includes information such as the correction trigger time, the deviation amount, the phase compensation amount of each array element, and the corrected focusing position.

[0042] In some other embodiments of this application, the imaging processing module is also used to monitor the echo signal of the target area in real time during the process of the phased array ultrasound array being controlled by the drive control module to emit the first ultrasound pulse sequence for focused ultrasound stimulation, and to determine whether the focusing position of the first ultrasound pulse sequence deviates from the expected position of the target stimulation point based on the echo signal.

[0043] Specifically, in this embodiment, the imaging processing module is also used to monitor the echo signal of the target area in real time during the process of the phased array ultrasound array being controlled by the drive control module to emit the first ultrasound pulse sequence for focused ultrasound stimulation. Furthermore, during the stimulation pulse emission and for a very short time after emission, the imaging processing module continuously receives echo signals from the target area. By performing real-time analysis of the echo signals, including echo amplitude monitoring and echo time shift monitoring, it determines whether the focused position of the first ultrasound pulse sequence deviates from the expected position of the target stimulation point. If a deviation in the focused position is detected during stimulation (e.g., due to slight movement of the user's head), the imaging processing module immediately sends a deviation signal to the drive control module, which then performs real-time correction of the focused position of the first ultrasound pulse sequence before the next frame of stimulation is emitted.

[0044] The transcranial ultrasound visual stimulation closed-loop system of this application has several beneficial effects. Regarding focusing accuracy, by detecting and pre-correcting micro-displacements of brain tissue before transmission, dynamic focusing errors caused by heartbeat and respiration are eliminated. Regarding stimulation effectiveness, the stimulation effect is directly verified through functional ultrasound imaging, and the driving parameters are automatically corrected based on the feedback results, solving the problem that open-loop systems cannot confirm the stimulation effect. Regarding long-term stability, through self-calibration of the visual topology mapping model based on functional ultrasound imaging feedback, the system continuously optimizes during use, overcoming individual differences and model errors. Regarding safety, by monitoring the echo signal in real time during stimulation, focusing shifts can be detected and corrections triggered promptly, providing proactive safety assurance.

[0045] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A transcranial ultrasound visual stimulation closed-loop system, characterized in that, include: The drive control module is used to determine the drive parameters of each target stimulus point on the visual cortex based on the image data corresponding to the acquired target image. An imaging processing module is used to control the phased ultrasound array to emit a probe ultrasound pulse sequence toward the visual cortex before the drive control module controls the phased ultrasound array to emit a first ultrasound pulse sequence, receive the echo signal of the probe ultrasound pulse sequence, and determine the initial position of the target region of the visual cortex based on the echo signal. The drive control module is also used to pre-correct the drive parameters of the first ultrasound pulse sequence according to the deviation between the initial position and the expected position of the target stimulation point, and control the phased ultrasound array to emit the first ultrasound pulse sequence toward the visual cortex for focused ultrasound stimulation. The imaging processing module is also used to control the phased array ultrasound array to transmit an imaging ultrasound pulse sequence to the visual cortex within a first predetermined time window after the first ultrasound pulse sequence is transmitted, receive the echo signal of the imaging ultrasound pulse sequence, and reconstruct a functional ultrasound image of the target region of the visual cortex based on the echo signal. A feedback correction module is used to determine the actual activation position of the target region of the visual cortex based on the functional ultrasound image, compare the actual activation position with the expected position of the target stimulation point, and if the deviation exceeds a preset threshold, correct the phase delay of each array element to adjust the focusing position of the first ultrasound pulse sequence to be emitted next; wherein, the imaging ultrasound pulse sequence is a plane wave ultrasound pulse sequence, and the reconstruction of the functional ultrasound image of the target region of the visual cortex based on the echo signal includes: the imaging processing module performs beamforming processing on the echo signal to generate an ultrafast ultrasound image sequence of the target region, and performs power Doppler imaging processing on the ultrafast ultrasound image sequence to generate a cerebral blood flow change map of the target region as the functional ultrasound image.

2. The transcranial ultrasound visual stimulation closed-loop system according to claim 1, characterized in that, Determining the initial position of the visual cortex target region based on the echo signal includes: The imaging processing module performs pulse-echo correlation calculations on the echo signals of the probe ultrasound pulse sequence to obtain the initial displacement of the target region along the direction of each array element's acoustic beam, and determines the initial three-dimensional spatial coordinates of the target region based on the initial displacement.

3. The transcranial ultrasound visual stimulation closed-loop system according to claim 2, characterized in that, It also includes an electrocardiogram (ECG) signal acquisition module for acquiring the user's ECG signal; the drive control module determines the cardiac cycle phase based on the R-wave trigger time of the ECG signal, and controls the phased-array ultrasound to transmit the first ultrasound pulse sequence within the phase window where the brain tissue displacement velocity is the minimum during the cardiac cycle.

4. The transcranial ultrasound visual stimulation closed-loop system according to claim 3, characterized in that, The correction of the phase delay of each array element includes: The feedback correction module determines the phase compensation amount of each array element based on the spatial deviation between the actual activation position and the expected position, and superimposes the phase compensation amount onto the driving phase of each array element.

5. The transcranial ultrasound visual stimulation closed-loop system according to claim 4, characterized in that, The feedback correction module further determines the correction amount of the visual topology mapping model based on the spatial deviation amount, and updates the visual topology mapping model based on the correction amount to correct the mapping relationship between the pixel coordinates and cortical coordinates corresponding to the target stimulus point.

6. The transcranial ultrasound visual stimulation closed-loop system according to claim 5, characterized in that, The feedback correction module also determines the activation intensity of the actual activation location based on the functional ultrasound image, compares the activation intensity with the preset target intensity, and adjusts the sound pressure amplitude parameter of the first ultrasound pulse sequence based on the comparison result.

7. The transcranial ultrasound visual stimulation closed-loop system according to claim 6, characterized in that, The feedback correction module keeps the current driving parameters unchanged when the deviation is less than or equal to the preset threshold, and triggers correction and records the correction log when the deviation exceeds the preset threshold.

8. The transcranial ultrasound visual stimulation closed-loop system according to claim 7, characterized in that, The imaging processing module is also used to monitor the echo signal of the target area in real time during the process of the phased array ultrasound array being controlled by the drive control module to emit the first ultrasound pulse sequence for focused ultrasound stimulation, and to determine whether the focusing position of the first ultrasound pulse sequence deviates from the expected position of the target stimulation point based on the echo signal.

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