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CN-122006155-A - Focusing sound field generation system and method based on three-dimensional transcranial ultrasonic imaging

CN122006155ACN 122006155 ACN122006155 ACN 122006155ACN-122006155-A

Abstract

The invention discloses a focusing sound field generation system and method based on three-dimensional transcranial ultrasonic imaging, relates to the technical field of ultrasonic imaging and acoustic focusing, and solves the technical problem that a focusing focus has obvious space deviation from a target point. On the premise of meeting the safety threshold parameters, multi-objective optimization is carried out on the array element phases, the amplitudes, the frequency bands and the emission time sequences of the multi-layer annular array according to the three-dimensional acoustic spectrum, and the individual focusing parameters and the acoustic dose parameters aiming at the preset brain region are obtained. The ultrasonic self-imaging-based personalized modeling and imaging-regulation closed loop integration is realized, and low-cost, repeatable and real-time three-dimensional transcranial imaging and accurate nerve regulation and control guidance can be provided in a bedside environment.

Inventors

  • LI ZHENGYU
  • YIN FENG
  • WANG XIYUAN
  • MA YINJIE

Assignees

  • 东南大学

Dates

Publication Date
20260512
Application Date
20260304

Claims (10)

  1. 1. A focused sound field generation system based on three-dimensional transcranial ultrasound imaging, comprising: the head-mounted three-dimensional ultrasonic transducer module (10) is used for being attached to the head of a subject to perform ultrasonic transmission and echo reception; The front end driving and collecting module (20) is used for performing high-voltage driving, transmitting or receiving switching and multichannel three-dimensional full-aperture ultrasonic signal collection on each array element of the head-mounted three-dimensional ultrasonic transducer module (10); The imaging and acoustic modeling module (30) is used for inverting the acquired three-dimensional full-aperture ultrasonic signals based on a three-dimensional wave equation, performing joint inversion on sound velocity, attenuation and density parameters of skull and brain tissues to obtain a three-dimensional acoustic map covering the whole brain, and executing three-dimensional structural imaging and three-dimensional functional ultrasonic imaging under the constraint of the three-dimensional acoustic map; The system comprises a focusing control module and a beam optimization module (40), wherein a multi-objective optimization model is constructed under the constraint of a three-dimensional acoustic map as a safety condition, the phase, the amplitude, the frequency band and the emission time sequence of each array element of the head-mounted three-dimensional ultrasonic transducer module (10) are calculated according to the objective optimization model, the individual focusing parameters and acoustic dose parameters aiming at one or more preset brain areas are obtained, and sound field focusing is carried out according to the focusing parameters and the acoustic dose parameters so as to determine a focusing point, wherein the safety condition comprises a mechanical index MI, a thermal index TI, space average time and average sound intensity.
  2. 2. The focused sound field generation system of claim 1, wherein the focused sound field generation system further comprises: the closed-loop monitoring and safety control module (50) is used for identifying focus position deviation, energy deposition abnormality and potential cavitation event, carrying out on-line evaluation and self-adaptive adjustment on focus parameters based on the focus position deviation, the energy deposition abnormality and the potential cavitation event, and triggering automatic power reduction or shutdown protection when the safety parameters exceed the limit; and the man-machine interaction and navigation module (60) is used for carrying out three-dimensional superposition display on the three-dimensional acoustic map, the three-dimensional structural imaging and the three-dimensional functional ultrasonic imaging, supporting the presetting or interactive selection of transcranial nerve regulation and control targets by a user and realizing standard alignment display and registration with external images.
  3. 3. A focused sound field generation system according to claim 2, wherein the three-dimensional wave equation is expressed as: ; Wherein, the Representing the spatial location; representing angular frequency; representing the frequency domain sound pressure; representing the speed of sound; Representing density; And (3) with All represent power law attenuation parameters; representing a sound source; Representing imaginary units; representing a laplace operator; the three-dimensional acoustic map is expressed as: ; ; Wherein, the Representing the data mismatch term(s), The regularization term is represented as a function of the regularization term, Representing the measured acoustic signal(s), Representing the analog acoustic signal(s), The transmission index is represented as such, Representing the reception index of the received data, Representing normalized cross-correlation; Representing parameters to be inverted; representing a priori, including an image priori and a velocity priori; 、 、 、 all represent weighting coefficients; Representing sound field Is a spatial gradient of (2); constraints in the inversion and the joint inversion process are expressed as: ; Wherein, the Represent the first The parameters of the wheel are set to be, Represent the first The frequency band of the respective one of the frequency bands, Representing the overall objective function.
  4. 4. A focused sound field generation system according to claim 3, wherein the multi-objective optimization model is expressed as: , , ; , ; ; , , , ; Wherein, the Representing complex sound pressure vectors of all sampling points; representing an acoustic propagation matrix from the array element to the sampling point; Representing complex weights of the array elements; Representing a propagation matrix of the corresponding target point; Representing target propagation vectors Is a conjugate transpose of (2); represents the density of the target point, Representing the speed of sound at the target point; Representing a mechanical index; A numerical value representing the ultrasonic operating frequency or center frequency in MHz; Representing the unattenuated radiation pressure amplitude; Representing the time-averaged sound intensity of the unattenuated spatial peak; representing the sound intensity of the de-attenuation; representing a bone window energy proxy matrix; Representing the side lobe region sampling matrix, Representing a matrix of samples of the constrained region, Representing side lobe suppression penalty weights; Representing bone window energy load penalty weights; Representing a time average window length; representing a maximum power upper limit; Representing an allowable upper threshold of the unattenuated spatial peak time average sound intensity; representing the upper threshold of sound pressure or energy of the confined area.
  5. 5. The focused sound field generating system according to claim 4, wherein the head-mounted three-dimensional ultrasonic transducer module (10) is an imaging-adjusting integrated three-layer coaxial array ultrasonic transducer, the three-layer coaxial array ultrasonic transducer comprises three-layer coaxial arrays, the three-layer coaxial arrays comprise a first annular array layer, a second annular array layer and a third annular array layer which are distributed along the axial direction from top to bottom, the first annular array layer, the second annular array layer and the third annular array layer are concentric circles, the diameters of the first annular array layer, the second annular array layer and the third annular array layer are 22cm, and each annular array layer at least comprises 512 independent array elements.
  6. 6. The focused sound field generating system according to claim 5, wherein the annular array element spacing of the three concentric arrays is 0.5 mm-1 mm, the layer spacing along the axial direction between the annular array layers is 2mm, the array element material is made of piezoelectric ceramic material or piezoelectric composite material, the effective working frequency band of the array element covers 0.1 MHz-1.2 MHz, and the effective working frequency band of the array element takes 0.8MHz as the center frequency.
  7. 7. The focused sound field generation system of claim 6, wherein the front-end drive and acquisition module (20) comprises a multi-channel transmit/receive and phased array control sub-module and a data acquisition and host processing sub-module electrically connected thereto, wherein: The multi-channel transmitting/receiving and phased array control submodule is used for outputting a multi-band pulse signal and a coding transmitting signal, and performing high-voltage driving, transmitting or receiving switching on each array element through the multi-band pulse signal and the coding transmitting signal, wherein the multi-band pulse signal comprises a narrow-band pulse signal and a linear chirp signal, and the coding transmitting signal comprises a complementary coding signal; The data acquisition and upper computer processing submodule is used for acquiring a multichannel three-dimensional full-aperture ultrasonic signal, and performing gain control, anti-aliasing filtering and A/D conversion on the multichannel three-dimensional full-aperture ultrasonic signal, wherein the sampling rate is not lower than 10MHz.
  8. 8. The focused sound field generation system of claim 7, wherein the closed loop monitoring and safety control module (50) comprises: The passive acoustic monitoring and functional imaging sub-module is used for collecting echo phases, passive acoustic monitoring signals and functional ultrasonic blood flow responses of a target area and an adjacent area in real time in the transcranial ultrasonic nerve regulation and control process, monitoring thermal expansion of a bone window and change of sound velocity of tissue through drift of the echo phases, monitoring potential cavitation events and abnormal scattering through the passive acoustic monitoring signals, and evaluating nerve regulation and control effects through the functional ultrasonic blood flow responses so as to identify focus point deviation, abnormal energy deposition and potential cavitation events; The safety monitoring and closed-loop control sub-module is used for carrying out on-line evaluation and self-adaptive adjustment on the focusing parameters based on the focus point position deviation, the energy deposition abnormality and the potential cavitation event, and triggering automatic power reduction or shutdown protection when the safety parameters exceed the limit, wherein the self-adaptive adjustment comprises real-time adjustment of the transmitting power, the pulse repetition frequency, the duty ratio and the array element phase.
  9. 9. A focused sound field generation system according to claim 8, characterized in that the man-machine interaction and navigation module (60) is integrated in the imaging and acoustic modeling module (30) or in a host processing terminal or separately.
  10. 10. A focused sound field generation method based on three-dimensional transcranial ultrasound imaging, the focused sound field generation method being realized by the focused sound field generation system according to any one of claims 1 to 9, comprising: Performing multiband and wide-solid-angle ultrasonic transmission and echo reception on the head of the subject through the head-mounted three-dimensional ultrasonic transducer module (10), and performing high-voltage driving, transmission or reception switching and multi-channel signal acquisition on each array element of the head-mounted three-dimensional ultrasonic transducer module (10) through the front-end driving and acquisition module (20) in the ultrasonic transmission and echo reception process so as to obtain a multi-channel three-dimensional full-aperture ultrasonic signal covering the head of the subject; the imaging and acoustic modeling module (30) inverts the acquired three-dimensional full-aperture ultrasonic signals based on a three-dimensional wave equation, performs joint inversion on sound velocity, attenuation and density parameters of skull and brain tissues to obtain a three-dimensional acoustic map covering the whole brain, and performs three-dimensional structural imaging and three-dimensional functional ultrasonic imaging under the constraint of the three-dimensional acoustic map; The focusing control module and the beam optimization module (40) construct a multi-target optimization model under the constraint of a three-dimensional acoustic map as a safety condition, calculate the phase, amplitude, frequency band and emission time sequence of each array element of the head-mounted three-dimensional ultrasonic transducer module (10) according to the target optimization model to obtain individual focusing parameters and acoustic dose parameters aiming at one or more preset brain areas, and perform sound field focusing according to the focusing parameters and the acoustic dose parameters to determine a focusing point, wherein the safety condition comprises a mechanical index MI, a thermal index TI, space average time and average sound intensity.

Description

Focusing sound field generation system and method based on three-dimensional transcranial ultrasonic imaging Technical Field The application relates to the technical field of ultrasonic imaging and sound focusing, in particular to a focusing sound field generation system and method based on three-dimensional transcranial ultrasonic imaging. Background The nerve regulation technique is a kind of technique which intervenes in the central nervous system and regulates the activity state of neurons by physical or chemical means so as to improve the motor, sensory and cognitive functions of patients. Currently, common invasive methods for neuromodulation include Deep Brain Stimulation (DBS), and the like, which, although having definite efficacy, require implantation of electrodes, present surgical risks, infection risks, and long-term maintenance costs. As a non-invasive alternative, transcranial focused ultrasound stimulation (TRANSCRANIAL FOCUSED ULTRASOUND, tFUS) has received much attention in recent years, which is capable of focusing ultrasound energy at specific areas deep in the brain without opening the skull, achieving reversible, regulatable neuromodulation, with higher spatial resolution and regulatory depth. In the prior art, in order to improve the accuracy of transcranial focusing, magnetic Resonance Imaging (MRI) or Computed Tomography (CT) is often relied on to provide anatomical information and skull structure parameters for guiding transducer positioning and target selection on the one hand, and for sound field simulation and phase correction on the other hand. However, MRI equipment is expensive, has long scanning time, is not friendly enough for emergency and bedside scenes, CT imaging involves ionizing radiation, has radiation exposure risk for patients, has limited contrast resolution for soft tissues, and increases the comprehensive burden of the patients and medical staff. In addition, although the existing partial scheme tries to combine skull information provided by MRI or CT to perform time reversal or ray tracing correction, the focusing process is often simplified to linear propagation in sound field simulation, and complex fluctuation behaviors such as multi-scattering, strong refraction, mode conversion and the like under the transcranial condition are not fully considered, so that obvious space deviation between a focusing focus and a target point can still be caused. Moreover, the scheme lacks real-time visualization and closed-loop evaluation of in-vivo sound field distribution and physiological response, and is difficult to discover risks such as focus drift, abnormal energy aggregation and the like in time. In the aspects of imaging and navigation, the existing transcranial ultrasonic application mainly relies on two-dimensional temporal window exploration, has limited visual field and serious window dependence, can only provide two-dimensional section information of a local brain region, and is difficult to realize unified assessment of the three-dimensional structure and function of the whole brain. Full waveform inversion (full waveform inversion, FWI) or ultrasonic tomography (USCT) based on acoustic fluctuation theory is introduced, acoustic parameter fields such as sound velocity, attenuation and the like of skull and brain tissues are directly inverted, imaging and focusing integration can be realized, but the method has the defects in the aspects of three-dimensional array engineering, CT-free modeling, experience verification, closed-loop standardized evaluation and the like. On the other hand, the development of ultra-fast ultrasound and functional ultrasound (functional ultrasound, fUS) technology has enabled the observation of cerebral hemodynamics at sub-second time resolution, which can be used to evaluate neural activity, functional connectivity and regulatory response. However, the existing transcranial ultrasonic system mostly separates imaging from regulation, imaging equipment and regulation equipment are independent, space registration is complex, target spot screening and dosage adjustment are difficult to be carried out by utilizing functional imaging results in time, and a systematic evaluation system and a unified index set which cover body model-ex-vivo-small animal/preclinical process are lacked, so that comparability among different systems and multi-center popularization are not facilitated. In summary, the prior art has at least the following problems: (1) Expensive or radiated imaging means such as MRI/CT are excessively depended on, so that bedside deployment and repeated monitoring are not facilitated; (2) The transcranial acoustic field modeling mostly adopts an approximate ray or a simplified model, so that multiple scattering and mode conversion caused by complex skull are difficult to accurately process, and the focus point still has deviation from a preset target point; (3) Imaging and regulation link fracture lack of three-dimensional navi