VARIATIONS IN IN-VIVO ELECTRICAL-IMPEDANCE TOMOGRAPHY IMAGES DUE TO INACCURACY IN BOUNDARY REPRESENTATION

A comparison of in vivo image results is performed for five image-reco nstruction programs, featuring an increase in accuracy of boundary mod elling from a simple 2-D disk to a true boundary shape with each curre nt drive field individually calculated. Variations are found both in t he positions of imaged features and their appearance,but reasonable co nsistency in reconstructed impedance changes is obtained for both phan tom : and in vivo data. In terms of quantitative measurements, the pro grams based on the simpler boundary assumptions generally perform more reliably than the more complex versions. It is concluded that the qua ntitative use of EIT with simple boundary assumptions is not compromis ed by body contour variations between patients, provided that the appr opriate regions of interest can be correctly identified.