Subsurface electrical impedance imaging: measurement strategy, image reconstruction and in vivo results

In conventional cross-sectional electrical impedance tomography, most of the spatial information is concentrated at the periphery of the image, close to the measurement electrodes. Increasing the number of electrodes tends not to increase the poor resolution at the centre of the cross-sectional image due to the physics of three-dimensional current flow. In this work an alternative approach. INSEIT (imaging near the surface by electrical impedance tomography), is explored in which the image plane lies at a selected depth in the object parallel to a surface electrode array. This approach has been investigated using a prototype data measurement system. The preliminary in vivo results include subsurface images of respiration, the gastro-intestinal tract and limb blood flow.