Enhancing Imaging Performance and Resolution in Magneto-Acoustic Electrical Tomography With Magnetic Field Measurements (MAET-MI) Using Figure-of-Eight and High-Quality Factor Circular Coils

Magneto-acousto-electrical tomography with magnetic field measurement technique (MAET-MI) is a hybrid imaging method that brings high spatial resolution of ultrasound imaging in electrical impedance tomography. This study investigates the impact of the quality factor of circular and figure-of-eight coils on the imaging performance of MAET-MI. Induced MAET signals on the circular coil are accurately obtained by modeling a circuit representation of an air-cored circular coil and deriving its transfer function through impedance measurements. The study demonstrates a significant improvement in signal-to-noise ratio (SNR) using high-quality factor coils compared to unity quality factor coils. Additionally, a 16-element linear phased array (LPA) ultrasound transducer, an air core circular coil, and a figure-of-eight coil are numerically modeled to obtain sector scan images of two-dimensional conductivity distributions. Point spread function (PSF) is characterized, and the lateral resolution of sector scan conductivity images is enhanced through two-dimensional deconvolution with PSF. The combined use of circular and figure-of-eight coils provides comprehensive imaging coverage. Notably, this research presents a practical method for estimating both circular and figure-of-eight coils' transfer functions, achieving 12.9 dB SNR improvement with high-quality factor coils. A simplified breast model is rotated 16 steps, and sector scan conductive boundary images are reconstructed for both coils. A two-dimensional image of a breast model is obtained by combining images from two different coils. These findings offer significant advancements in MAET-MI imaging, particularly in low SNR environments.