Transcranial acoustoelectric brain imaging reveals current field of deep brain stimulation with millivolt-level...

Objective.Deep brain stimulation (DBS) is a technology employed to stimulate the central nervous system, with amplitude being the main parameter for regulating DBS. Given the effectiveness of DBS therapy depends significantly on lead placement and stimulus intensity, it is crucial to accurately map the lead field and monitor dynamic changes of stimulus amplitude. Transcranial acoustoelectric brain imaging (tABI) has been initially proved as a non-invasive method for mapping DBS currents. This study utilizes tABI to map amplitude-varying DBS currents to explore its potential for DBS monitoring.Approach.tABI was applied to six living rats' brain while DBS was delivered with 50 mV amplitude increments. The tABI images of amplitude-varying DBS currents are analyzed for spatiotemporal resolution, while the method's capability to decode DBS current is evaluated in terms of amplitude, frequency, and time domains.Main results.The results show that tABI can map the lead field of DBS with millivolt-level amplitude resolution and reveal dynamic changes with ∼2 mm spatial resolution within a single stimulus period of 7.69 ms, achieving a mean SNR of 20.4 dB. With sensitivity of 167.74μV V^-1MPa^-1, the acoustoelectric intensity and stimulus amplitude exhibit a strong positive correlation, with a coefficient of determination ofR²= 0.9982 for the linear fit. Additionally, the decoded acoustoelectric signal exhibits a correlation coefficient above 0.819 with the DBS current in the time domain.Significance.This study first demonstrates that tABI can reveal the spatial distribution and dynamic changes ofin vivoDBS lead currents with millivolt-level amplitude resolution. Further validation in disease-relevant animal models is warranted to assess clinical translatability.