Three-dimensional magneto-acousto-electrical tomography (3D MAET) with single-element ultrasound transducer and coded excitation: A phantom validation study

Magneto-acousto-electrical tomography (MAET) is a hybrid imaging modality combining the merits of high contrast and high resolution. Current studies in MAET mainly focus on two-dimensional (2D) imaging. In practice, an object's conductivity is usually three-dimensional inhomogeneous. Therefore, three-dimensional MAET (3D MAET) may provide a more comprehensive understanding of the conductivity distribution of an object. The basic idea of realizing 3D MAET is to move the ultrasound transducer mechanically to accomplish the 3D scanning. However, this mechanical scanning procedure is time-consuming. Moreover, due to the weak MAE signal, traditional MAET based on single-pulse excitation requires thousands of signal averaging operations to improve the signal-to-noise ratio (SNR) of imaging, which may further increase the time burden of 3D MAET. This study aims to investigate the feasibility of 3D MAET based on a 1D ultrasound transducer and coded-excitation technology. A 13-bit Barker code was used as the excitation code, and two 3D biological phantoms were used to validate the imaging accuracy. The experimental results show that the imaging results of this method can reflect the change of conductivity in 3D space. The average relative errors of the measured slope of the conductivity distribution in Phantom 1 and Phantom 2 are 6.72% and 2.02%, respectively. Moreover, compared with the short-pulse excitation method, the Barker-coded excitation method can obtain comparative imaging SNR with about a quarter average, thus demonstrating the feasibility of 3D MAET with a single-element ultrasound transducer and coded excitation.