Comments on distinguishability in electrical impedance imaging

In electrical impedance imaging, the spatial distribution of electrical resistivity of a volume conductor is reconstructed from measurements of potential which result from an externally applied electric field. The ability of such a system to distinguish a target inhomogeneity and the discussion of several measures of distinguishability has been a subject of a recent study (ibid. vol.39, p.852-60 (1992)). The authors add a few comments to those of that study. The medical device safety regulations limit the maximum total input current which can be applied to the human thorax. Based on the currently existing safety regulations, if the input current to the thorax is limited and constant, patterns applied between opposite electrodes result in higher distinguishability of a centered target than the cosine current patterns as suggested by the previous study.<>