Correcting for variability in mesh geometry in finite element models

Abstract

We show that variability in the finite element model (FEM) geometry in the EIT forward model can result in image artefacts in the reconstructed images. We explain these artefacts as the result of changes in the projection of the anisotropic conductivity tensor onto the FEM system matrix. This introduces anisotropic components into the simulated voltages, which cannot be reconstructed onto an isotropic image, and appear as artefacts. In order to address this problem, we show that it is possible to incorporate a FEM vertex movement component into the formulation of the inverse problem. These results suggest that it may be important to consider artefacts due to FE mesh geometry in the formulation of EIT image reconstruction.