Direct reconstruction of tissue conductivity with deconvolution in magneto-acousto-electrical tomography (MAET): theory and numerical simulation

• Main Authors: Sun, Tong, Deng, Dingqian, Yu, Linguo, Chen, Yi, Chin, Chien Ting, Chen, Mian, Chang, Chungi, Chen, Siping, Lin, Haoming, Chen, Xin
• Format: Journal Article
• Language: English
• Published: 05-01-2022
• Subjects: Physics - Medical Physics
• DOI: 10.48550/arxiv.2201.01560

Magneto-acousto-electrical tomography (MAET), a combination of ultrasound
imaging and electrical impedance tomography (EIT), offers both high resolution
(in comparison to EIT) and high contrast (in comparison to ultrasound imaging).
It is used to map the internal conductivity distribution of an imaging object.
However, conductivity reconstruction in MAET is a challenge, so conventional
MAET is mainly devoted to mapping the conductivity interface. This is primarily
because integration byparts is used in the theory derivation, and the
simplified measurement formula suggests the voltage is proportional to the
conductivity gradient, which leads to an error in the measurement formula. In
this study, the measurement signal is expressed as the convolution of acoustic
velocity and conductivity distribution without using integration by parts,
which retains the low-frequency term in the measurement signal. Based on the
convolution formula, we subsequently propose a direct conductivity
reconstruction scheme with deconvolution by utilizing the low-frequency
component. We verify the proposed method based on two two-dimension models and
quantify the L2 errors of reconstructed conductivity. Besides, we analyze
factors influencing the reconstructed accuracy such as reconstructed
regularization parameter ultrasound frequency, and noise. We also demonstrate
that the spatial resolution is not influenced by the duration of excitation
ultrasound. With the contributions of the proposed method, conductivity imaging
appears to be feasible for application to the early diagnosis in the future.