Numerical Convergence of 3D Electrode Models used in Electrical Impedance Tomography

Abstract

Electrical Impedance Tomography is a technique that creates a medical image from measurements of electric potential taken at the skin. It depends on the accurate modelling of the voltage drop that happens due to transduction of electronic flow into ionic flow at electrode/skin interface. In this work, two of the existing electrode models (Nodal and Prismatic) were implemented and compared to two other proposed models. One of them (Pyramidal) is a variation of Prismatic model and the other (Patacon) is new, based on a finite element model with “thick” blocks representing electrode/skin interface. A qualitative study and a convergence analysis were conducted to compare the performance of the models. It was found that both proposed models converge and that they present electric potentials consistently above Prismatic model. Additionally, potentials estimated by Patacon model are consistently smaller than Pyramidal model.