The complete electrode model for EIT in a mammography geometry

Abstract

We have developed an EIT system for simultaneous use in a mammography examination, allowing for highly accurate co-registration between the two modalities. In this pre-clinical study, we investigate the importance of properly modeling the interface between the electrodes and the medium being imaged. We have implemented the complete electrode model for a parallel-plane mammography geometry, in which currents are injected into the medium through two planar sets of electrodes above and below the medium. We make use of the ACT4 device to conduct saline-tank experiments showing the improvement of the complete model over an ave-gap model, which ignores both the conductivity of the electrodes and the surface impedance. The experimental results show an improvement in both forward modeling accuracy and in the quality of the resulting reconstructed images using the complete electrode model, as compared to the ave-gap model.

Optimal Electrode Selection for Electrical Resistance Tomography in Carbon Fiber Reinforced Polymer Composites

“…The governing differential equation for the voltage distribution u in a body with a conductivity field σ under the spatial coordinates $\overline{r}$ is given by the following Laplace’s equation and associated boundary conditions (BC) [14,15,16]:$\nabla ·\mathit{\sigma }\nabla u=0,\overline{r}\in \Omega ,$ ${\int }_{el}\mathit{\sigma }\frac{\partial u}{\partial \overline{n}}dS=I,\overline{r}\in el,l=1,2,\dots ,L,$ $\mathit{\sigma }\frac{\partial u}{\partial \overline{n}}=0,\overline{r}\in \partial \Omega \backslash U_{l=1}^L{e}_l,$ $u+\xi \mathrm{bold-italic\sigma }\frac{\partial u}{\partial \overline{n}}=U_l,\overline{r}\in e_l,l=1,2,\dots ,L.$…”

Efficient Simultaneous Reconstruction of Time-Varying Images and Electrode Contact Impedances in Electrical Impedance Tomography

“…We denote the measurement at time 0, y (0), to be the “reference” measurement. Furthermore, we assume that our medium is well-described by the CEM and that we are able to compute the Jacobian matrices with respect to the contact impedances and the internal medium admittivities using previously-described methods [11], [12]. In our modeling, we use the finite-element method with customized meshes refined at the electrodes and we compute the Jacobian matrix with respect to changes in conductivity on the basis of tetrahedral elements.…”

“…A number of electrode models have been suggested for use in EIT [9], [10] and it appears that the model with the most practical utility is the “complete electrode model” (CEM), introduced in [10] and further studied in [11], [12], [13], [14]. However, the superiority of this model has been primarily demonstrated with saline tank and phantom studies.…”

Diagnostic System in Electrical Impedance Mammography: Background

“…Electrical impedance mammography (EIM) represents one of the most rapidly developing imaging modalities designed for breast cancer detection [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”