Magneto-Acousto-Electrical Tomography With Magnetic Induction for Conductivity Reconstruction

Abstract

Magneto-acousto-electrical tomography (MAET) is an imaging modality proposed to conduct noninvasive electrical conductivity imaging of biological tissue with high spatial resolution. In this study, we present a method of MAET in coil detection mode, which is named as magneto-acousto-electrical tomography with magnetic induction (MAET-MI). Based on the analysis of the mechanism of MAET-MI, we derive a reciprocal theorem and give an integral equation for computing the induced voltage of the coil. The forward problem of MAET-MI can be solved by this integral equation. In the inverse problem of MAET-MI, two steps are taken to reconstruct the conductivity. The first step is to reconstruct the curl of the eddy current density in the reciprocal process by the compression sensing method. And then the conductivity is recovered by the iterative methods such as the Levenberg-Marquardt algorithm. Both the mechanism of MAET-MI and the reconstruction of conductivity are verified by computer simulations. We have also conducted the phantom experiments. The reconstructed images are approximately consistent with the phantom's conductivity. The imaging results prove the ability and the reliability of our proposed methods. It is shown that the relative conductivity distribution can be reconstructed with our proposed reciprocal theorem in MAET-MI modality. Comparing with the traditional MAET, The MAET-MI modality would benefit from the noncontact measurement and be convenient for clinical application.

Magnetoacoustic tomography with magnetic induction (MAT-MI) for imaging electrical conductivity of biological tissue: a tutorial review

“…As a reverse model of MAT-MI, magneto-acousto-electrical tomography with magnetic induction MAET-MI (Guo et al , 2015a) was recently developed to map electrical conductivity using ultrasound stimulation and coil detection of the magnetic field generated by the Lorentz force induced current.…”

“…The static magnetic fields in MAET-MI systems are also created by permanent magnets, and the applied field strength ranges from 0.2-0.3 Tesla around the imaged object along z direction (Guo et al , 2015a). Depending on different system designs, the ultrasound stimulations may employ transducers working at different center frequencies, e.g.…”

“…In addition, similar to the reverse mode of HEI or MAET, i.e. applying ultrasound transmission and measuring the Lorentz force induced current or voltage for imaging electrical conductivity, the reverse mode of MAT-MI named magneto-acousto-electrical tomography with magnetic induction (MAET-MI) has also been developed recently (Guo et al , 2015b), which uses ultrasound stimulation and coil measurement of the dynamic magnetic field generated by Lorentz force induced current in conductive imaging objects.…”

Numerical Calculation Method for Magneto-Acoustic-Electrical Tomography of Acoustically Inhomogeneous Tissues

“…With conductivity as the imaging target parameter, it is more and more concerned with the advantages of non-invasive, good contrast and high sensitivity [1,2] . In the previous study of magneto-acoustic tomography, the researchers believe that the acoustic parameters of most of the biological tissues are near-unanimous, and the acoustic parameters are approximated by assuming that the biological tissues have homogeneous acoustic characteristics and inhomogeneous electrical characteristics [3] .…”

Effect of the secondary process on mass point vibration velocity propagation in magneto-acoustic tomography and magneto-acousto-electrical tomography

“…Xu developed magneto-acousto-electrical tomography with electrode detection [5,6]. Guo developed magneto-acousto-electrical tomography with coil detection (MAET-MI) [7].…”