Magneto-acoustic-electrical tomography combining maximum length sequence–coded excitation and liquid metal image contrast agent

Magneto-acoustic-electrical tomography (MAET) combines the advantages of ultrasound and electrical impedance functional tomography methods and has important research value in the early diagnosis of tumors and biocurrent monitoring. In this study, we propose a MAET method combining liquid metal image enhancement and maximum length sequence (MLS)–coded excitation to improve the signal-to-noise ratio (SNR) of MAET. The results indicate that liquid metal can achieve image enhancement of tissue MAET. When 7-, 15-, 31- and 63-bit MLS-coded excitations were applied to the samples, the SNR was improved by 28, 34, 40 and 45 dB, respectively. For a similar SNR improvement, the total used time under 31-bit MLS-coded excitation can be shortened to 23% under single-pulse excitation. The experimental results prove the feasibility of applying the MLS code to rotational MAET and reveal the significance of liquid metal as an image intensifier to improve the quality of MAET.