CN-121995286-A - Electromagnetic interference correction method and device compatible with magnetic resonance ultrasonic regulation and control

CN121995286ACN 121995286 ACN121995286 ACN 121995286ACN-121995286-A

Abstract

The invention discloses an electromagnetic interference correction method and device compatible with magnetic resonance ultrasonic regulation, which are characterized in that pure ultrasonic signals are extracted by ultrasonic coupling equipment to serve as references, the problem that an EMI probe cannot collect ultrasonic EMI is solved, meanwhile, a calibration signal and a magnetic resonance mixed signal are collected in the same TR, a multichannel covariance matrix is constructed based on the calibration signal, and then, the covariance matrix is utilized to carry out optimal linear combination on all signals in the magnetic resonance mixed signal, so that the EMI introduced by ultrasonic equipment is thoroughly eliminated.

Inventors

HUANG ZHENGYUAN
ZHU YUDONG
LUO HAI

Assignees

上海睿楫医疗科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260212

Claims (10)

1. A magnetic resonance ultrasound regulatory compatible electromagnetic interference correction method, characterized in that pure ultrasound signals are introduced by ultrasound coupling equipment when the ultrasound equipment is in operation, and the method comprises: Acquiring magnetic resonance mixed signals and calibration signals, wherein the magnetic resonance mixed signals comprise electromagnetic interference signals acquired by a plurality of electromagnetic interference (EMI) probes, noisy magnetic resonance signals acquired by a multi-channel main coil and actual ultrasonic signals acquired by ultrasonic coupling equipment, and the calibration signals comprise first calibration sub-signals acquired by the plurality of electromagnetic interference (EMI) probes, second calibration sub-signals acquired by the multi-channel main coil and pure ultrasonic signals acquired by the ultrasonic coupling equipment; taking the pure ultrasonic signal in the calibration signal as an ultrasonic EMI reference signal, and constructing a multichannel covariance matrix based on the ultrasonic EMI reference signal and a first calibration sub-signal and a second calibration sub-signal in the calibration signal; And carrying out optimal linear combination on the EMI interference signals, the noise-containing magnetic resonance signals and the actual ultrasonic signals in the magnetic resonance mixed signals by utilizing the multichannel covariance matrix so as to separate the magnetic resonance signals after eliminating the ultrasonic EMI from the magnetic resonance mixed signals after the optimal linear combination.
2. The method of claim 1, wherein constructing a multi-channel covariance matrix based on the ultrasonic EMI reference signal and the first and second calibration sub-signals of the calibration signals comprises: constructing the multi-channel covariance matrix according to the following formula; ; in the formula, Representing the multi-channel covariance matrix, Representing a second calibration sub-signal acquired by a first one of the multi-channel primary coils, Representing the second calibration sub-signal acquired by the nth main coil, Representing a first calibration sub-signal acquired by a first EMI probe, Representing a first calibration sub-signal acquired by an mth EMI probe, Representing the ultrasonic EMI reference signal, an Representing a conjugate transpose operation.
3. The method of claim 1, wherein using the multi-channel covariance matrix optimally linearly combines the EMI interference signal, the noisy magnetic resonance signal, and the actual ultrasound signal in the magnetic resonance hybrid signal to separate the ultrasound EMI canceled magnetic resonance signal from the magnetic resonance hybrid signal after optimal linear combination, comprising: Calculating an inter-channel linear combination coefficient in the magnetic resonance mixed signal based on the multi-channel covariance matrix; And carrying out channel weighted combination processing on the EMI interference signals, the noise-containing magnetic resonance signals and the actual ultrasonic signals in the magnetic resonance mixed signals according to the inter-channel linear combination coefficient so as to separate the magnetic resonance signals after eliminating the ultrasonic EMI from the magnetic resonance mixed signals after the channel weighted combination processing.
4. The method of claim 3, wherein calculating inter-channel linear combination coefficients in the magnetic resonance hybrid signal based on the multi-channel covariance matrix comprises: solving an inverse matrix of the multi-channel covariance matrix to obtain the inter-channel linear combination coefficient; correspondingly, according to the inter-channel linear combination coefficient, performing channel weighted combination processing on the EMI interference signal, the noise-containing magnetic resonance signal and the actual ultrasonic signal in the magnetic resonance mixed signal, and then includes: Carrying out channel weighted combination treatment on the EMI interference signal, the noise-containing magnetic resonance signal and the actual ultrasonic signal in the magnetic resonance mixed signal by adopting the following formula so as to separate the magnetic resonance signal from the magnetic resonance mixed signal after eliminating the ultrasonic EMI; ; in the formula, Representing the magnetic resonance signal after the elimination of the ultrasonic EMI, Representing the magnetic resonance mixed signal, Representing the multi-channel covariance matrix, And representing an inverse of the multi-channel covariance matrix.
5. The method of claim 1, wherein the calibration signal is acquired after a noisy magnetic resonance signal in the magnetic resonance hybrid signal.
6. The method of claim 1, wherein the ultrasound coupling device comprises an ultrasound transmitter, a signal transmitter, a nuclear magnetic resonance spectrometer, and an ultrasound transducer; the ultrasonic transmitter, the signal transmitter and the nuclear magnetic resonance spectrometer are all placed in the shielding cabinet, the output end of the ultrasonic transmitter is electrically connected with the input end of the signal transmitter, the output end of the signal transmitter is respectively electrically connected with the ultrasonic transducer and the nuclear magnetic resonance spectrometer, and the ultrasonic transmitter is used for coupling and transmitting signals output to the ultrasonic transducer to the nuclear magnetic resonance spectrometer through the signal transmitter so as to acquire pure ultrasonic signals based on the nuclear magnetic resonance spectrometer.
7. The method of claim 6, wherein the ultrasound coupling device further comprises a low pass filter and the ultrasound transmitter is electrically connected to the signal transmitter through the low pass filter.
8. An electromagnetic interference correction device compatible with magnetic resonance ultrasonic regulation and control, which is characterized in that pure ultrasonic signals are introduced into the ultrasonic equipment through ultrasonic coupling equipment when the ultrasonic equipment operates, and the device comprises: The system comprises an acquisition unit, a calibration unit and a control unit, wherein the acquisition unit is used for acquiring magnetic resonance mixed signals and calibration signals acquired in the same TR time, the magnetic resonance mixed signals comprise EMI interference signals acquired by a plurality of EMI probes, noisy magnetic resonance signals acquired by a multi-channel main coil and actual ultrasonic signals acquired by ultrasonic coupling equipment, and the calibration signals comprise first calibration sub-signals acquired by the plurality of EMI probes, second calibration sub-signals acquired by the multi-channel main coil and pure ultrasonic signals acquired by the ultrasonic coupling equipment; The covariance matrix construction unit is used for taking the pure ultrasonic signals in the calibration signals as ultrasonic EMI reference signals and constructing a multichannel covariance matrix based on the ultrasonic EMI reference signals, first calibration sub-signals and second calibration sub-signals in the calibration signals; And the interference correction unit is used for carrying out optimal linear combination on the EMI interference signal, the noise-containing magnetic resonance signal and the actual ultrasonic signal in the magnetic resonance mixed signal by utilizing the multichannel covariance matrix so as to separate the magnetic resonance signal after eliminating the ultrasonic EMI from the magnetic resonance mixed signal after the optimal linear combination.
9. An electronic device comprising a memory, a processor and a transceiver in communication with each other in sequence, wherein the memory is configured to store a computer program, the transceiver is configured to transmit and receive a message, and the processor is configured to read the computer program and execute the electromagnetic interference correction method compatible with magnetic resonance ultrasound control according to any one of claims 1 to 7.
10. A computer program product comprising instructions which, when run on a computer, cause the computer to perform the magnetic resonance ultrasound compatible electromagnetic interference correction method of any one of claims 1 to 7.

Description

Electromagnetic interference correction method and device compatible with magnetic resonance ultrasonic regulation and control Technical Field The invention belongs to the technical field of magnetic resonance imaging, and particularly relates to an electromagnetic interference correction method and device compatible with magnetic resonance ultrasonic regulation. Background The Magnetic Resonance Imaging (MRI) has become a core monitoring tool for clinical diagnosis and accurate medical treatment by virtue of the advantages of no ionizing radiation, high soft tissue resolution, multi-parameter imaging and real-time visualization, the ultrasonic regulation and control technology has the characteristics of no wound, strong targeting, convenient operation and great application potential in the fields of neuroscience research, tumor treatment, rehabilitation medicine and the like, wherein a magnetic resonance guided focused ultrasound system (Magnetic Resonance-guided Focused Ultrasound, MRgFUS) can form a closed loop of 'real-time monitoring-accurate regulation and control', the MRI provides anatomical positioning, target spot visualization and effect evaluation for ultrasonic regulation and control, the ultrasound realizes noninvasive intervention on target tissues, and solves the limitation that the traditional ultrasonic regulation and control is 'blind' and MRI can only monitor and cannot be interfered, so the magnetic resonance guided focused ultrasound system has irreplaceable clinical value in the scenes such as brain function regulation and control, tumor accurate thermotherapy, cardiovascular disease intervention and the like. In practical application, the ultrasonic control equipment can generate high-frequency electromagnetic signals when in operation, harmonic components of the high-frequency electromagnetic signals possibly fall into the radio frequency receiving bandwidth of MRI (magnetic resonance imaging), the harmonic components become a 'noise source' for MRI signal acquisition, meanwhile, vibration driving signals of the ultrasonic transducer can form electromagnetic interference through cables and metal parts, so that banding artifacts appear on MRI images, the signal to noise ratio is reduced, and even key anatomical details are lost, therefore, the ultrasonic EMI interference in the magnetic resonance signals needs to be removed when the magnetic resonance guided focused ultrasound is applied. At present, the mode of removing ultrasonic EMI interference mainly comprises (1) prior art 1 with application number CN201780095470.2 discloses a method for reducing electromagnetic interference when operating an electrically driven ultrasonic thermal treatment device, which reduces EMI from an ultrasonic control system source by dynamically adjusting the phase of a multi-transducer driving signal, counteracts electromagnetic radiation, (2) paper External DYNAMIC INTERFERENCE Estimation and Removal (EDITER) for Low Field MRI (hereinafter referred to as prior art 2) calculates the linear relation between an EMI probe and a main coil correction signal by a least square method, uses EMI probe data to fit the noise interference data of the main coil and subtracts the noise interference data in the main coil to achieve the purpose of removing noise interference, and (3) paper Inter Channel Correlation-Based EMI Noise Removal (ICER) for Shielding-Free Low-Field MRI (hereinafter referred to as prior art 3) generates a decorrelation matrix by collecting the EMI probe calibration signal and the multi-channel calibration signal and combining operation, so as to decompose the signal into a plurality of independent sources, thereby achieving the interference removing effect. However, the calibration algorithm provided by the prior art relies on a priori model, the adjustment of the phase is based on a space distribution model of the transducer radiation electromagnetic field, the array structure (such as a linear array, a convex array and a special-shaped array in a cavity) of the ultrasonic probe in clinic has large difference, an exclusive calibration model needs to be customized for each array, the steps are complicated, the power in the ultrasonic regulation and control process needs to be dynamically adjusted along with clinical requirements, the phase parameters need to be recalculated at the moment, so that delay or an EMI burst is caused, (2) the prior art needs to ensure that the EMI probe can completely collect the interference signals received by the main coil, however, the ultrasonic EMI cannot be collected by the EMI probe, so that the method can only eliminate environmental EMI and cannot eliminate ultrasonic EMI, and (3) the prior art 3 breaks down each channel signal into independent sources and uses an EMI channel to accommodate the interference signals, when the EMI probe and the multiple channels do not collect the interference signals at the same time, the interference signals are difficult