Simultaneous reconstruction of conductivity, boundary shape and contact impedances in electrical impedance tomography

TL;DR

This paper presents a novel method for simultaneously reconstructing conductivity, boundary shape, and contact impedances in electrical impedance tomography, improving accuracy in medical imaging applications.

Contribution

The paper introduces a three-step approach that jointly estimates conductivity, boundary shape, and contact impedances from EIT data, addressing errors caused by unknown boundary and contact properties.

Findings

Robust and accurate reconstructions demonstrated on experimental data.

Method effectively reduces artifacts caused by boundary and contact impedance errors.

Joint reconstruction improves the quality of EIT images in practical scenarios.

Abstract

The objective of electrical impedance tomography (EIT) is to reconstruct the internal conductivity of a physical body based on current and voltage measurements at the boundary of the body. In many medical applications the exact shape of the domain boundary and contact impedances are not available. This is problematic as even small errors in the boundary shape of the computation domain or in the contact impedance values can produce large artifacts in the reconstructed images which results in a loss of relevant information. A method is proposed that simultaneously reconstructs the conductivity, the contact impedances and the boundary shape from EIT data. The approach consists of three steps: first, the unknown contact impedances and an anisotropic conductivity reproducing the measured EIT data in a model domain are computed. Second, using isothermal coordinates, a deformation is constructed that makes the conductivity isotropic. The final step minimizes the error of true and reconstructed known geometric properties (like the electrode lengths) using conformal deformations. The feasibility of the method is illustrated with experimental EIT data, with robust and accurate reconstructions of both conductivity and boundary shape.