A Fidelity-embedded Regularization Method for Robust Electrical Impedance Tomography

TL;DR

This paper introduces a fidelity-embedded regularization method for electrical impedance tomography that enhances image stability and quality from noisy data, with potential clinical benefits.

Contribution

The paper proposes a novel FER method that incorporates Jacobian matrix analysis to improve robustness and fidelity in EIT image reconstruction, independent of regularization parameter choice.

Findings

Stable high-fidelity images from noisy data demonstrated in experiments.

Effective motion artifact removal in chest EIT imaging.

Method outperforms traditional regularization techniques in robustness.

Abstract

Electrical impedance tomography (EIT) provides functional images of an electrical conductivity distribution inside the human body. Since the 1980s, many potential clinical applications have arisen using inexpensive portable EIT devices. EIT acquires multiple trans-impedance measurements across the body from an array of surface electrodes around a chosen imaging slice. The conductivity image reconstruction from the measured data is a fundamentally ill-posed inverse problem notoriously vulnerable to measurement noise and artifacts. Most available methods invert the ill-conditioned sensitivity or Jacobian matrix using a regularized least-squares data-fitting technique. Their performances rely on the regularization parameter, which controls the trade-off between fidelity and robustness. For clinical applications of EIT, it would be desirable to develop a method achieving consistent performance over various uncertain data, regardless of the choice of the regularization parameter. Based on the analysis of the structure of the Jacobian matrix, we propose a fidelity-embedded regularization (FER) method and a motion artifact removal filter. Incorporating the Jacobian matrix in the regularization process, the new FER method with the motion artifact removal filter offers stable reconstructions of high-fidelity images from noisy data by taking a very large regularization parameter value. The proposed method showed practical merits in experimental studies of chest EIT imaging.