The Research Of Noninvasive Detection Method Of Electrical Stimulation Tissue Current Based On Magneto-Acoustic Effect

Electrical stimulation is widely used in nerve regulation and treatment.The detection of the distribution of stimulation current in tissues is of great significance to improve the accuracy of electrical stimulation.However,due to the complex distribution of electrical properties of tissue,it is still difficult to achieve non-invasive detection of stimulation current.This study proposes a non-invasive detection method of electrical stimulation current based on the magneto-acoustic effect,which has the advantages of high spatial resolution and high spatial contrast.In this study,a theoretical model of frequency domain sound source based on magneto-acoustic effect is derived by using the principle of magneto-acoustic effect.Based on the sine wave electrical stimulation,the frequency domain magneto-acoustic signal is solved,and the frequency domain magnetic acoustic signal at the sound source position under the sine wave excitation is obtained under the condition of known tissue conductivity distribution information.Combined with the lock-in amplification detection method,the high-precision detection and extraction of magnetic acoustic signals is realized.In this study,the finite element analysis software ANSYS is used to carry out finite element analysis and calculation of the positive electromagnetic field problem on the simulation model of continuous sinusoidal electrical stimulation with a loading frequency of 20kHz in the static magnetic field.The results show that the current density distribution is closely related to the conductivity characteristics and electrode position.The stimulation current is concentrated near the electrodes,and the current density is gradually reduced at the position of the electrode connection near the midpoint.With the increase of the spacing between the two electrodes,the current density distribution gradually diverges,the depth of the stimulation current increases gradually,and the depth of the magnetic-acoustic sound source increases.In this study,a research platform for electrical stimulation current detection and imaging based on magnetic-acoustic effect is established,and the measurement accuracy of magneto-acoustic signal reaches 10-7Pa-10-9Pa,which realizes the stimulation voltage of 10V and the two-dimensional stimulation current distribution under the intensity of 0.01 A stimulation current,and the measurement space accuracy is 2 mm.At the same time,the stimulation current detection of in vivo animals was preliminarily studied,and the results showed that the current distribution and electrical stimulation intensity in the tissue increased linearly,the electrode spacing increased the sound source depth increased,and the current distribution trend was consistent with the simulation results.In short,the noninvasive electrostimulation tissue current imaging method based on magnetic-acoustic effect proposed in this study is of great significance for realizing the non-invasive measurement of the distribution of stimulation current in tissues,optimizing the parameters of electrical stimulation,and improving the targeting of electrical stimulation therapy,and plays an active role in the study of tissue rehabilitation research and neuromodulation mechanism of electrical stimulation.