A two-dimensional reconstruction algorithm based on a modified version of the method of sensitivity regions is used to reconstruct data obtained from a three-dimensional finite element model. By using data obtained from off-drive-plane measurements an improved image of changes in resistivity on the drive plane is obtained.<>

A 2-d finite element model is used to simulate the adult head. The effect of gross variations of skull thickness on the sensitivity of measurement pairs to areas within the model are obtained. The implications of these measurements for electrical impedance tomography of the adult brain are discussed. Inter-patient variability of the adult skull may be a key factor in electrical impedance tomography of the adult head.

A new technique is described which exploits capacitively coupled non-electrolyte electrodes to allow two electrodes measurement of tissue section impedance. By inductively cancelling the electrode capacitance the exciting voltage is applied directly across this section. The series impedance thus measured is then only of the tissue.

Sensitivity coefficients for changes in resistivity of individual voxels within the object are dependant upon the change in resistivity within other voxels. This is demonstrated using finite element models for both on and off-plane perturbations. It is proposed that more appropriate finite element models of body sections will elicit more information for practical electrical impedance tomography reconstruction algorithms.