Multi-Electrode Acoustoelectric Imaging of Current Source Density via Scalar Potential Reconstruction: Feasibility Study in a Cube Phantom.

Acoustoelectric (AE) imaging has the potential to reconstruct current sources with high spatial and temporal resolution. However, a significant challenge is low signal-to-noise ratio (SNR), which complicates source detection and ultimately degrades spatial resolution. In this study, we propose a novel multi-electrode reconstruction method to image the current source density (CSD) in biological tissue at high image frame rates. This approach reconstructs the scalar potential of the current source with only single-step inversion regardless of the number of electrodes. It effectively removes modulation effects caused by acoustic and electrical-lead fields to obtain an unmodulated representation of the CSD. The approach was validated using a simple bio-mimicking cube phantom, with two stimulus electrodes to simulate current sources and six recording electrodes to capture AE signals. A 1.5D ultrasound transducer array operating at 0.6 MHz with focused beam scanning generated 2D AE signals for CSD reconstruction. Accurately modeled acoustic and lead fields were used in reconstruction through regularized inversion with truncated singular value decomposition (TSVD). The reconstructed scalar potential of the current source demonstrated improved spatial resolution with up to a 33 percent decrease in the area of the image point spread function and a 7 dB increase in SNR compared to raw AE signals for the small set of electrodes used. Moreover, the results were in strong agreement with simulated ground truth.