A Pilot Study For Tissue Characterisation Using Bioimpedance Mapping

Abstract

Bioimpedance has shown potential as a method for characterising biological tissue with the use of the tetrapolar electrode configuration. This configuration has been shown to distinguish between normal squamous epithelium and Cervical Intra-epithelial Neoplasia (CIN) [1]. The tetrapolar configuration has also been shown to produce anomalous results in the form of an increase in measured impedance when a low impedance lesion is located between a drive and measurement electrode [2]. We have investigated a possible solution to this problem using bioimpedance mapping employing an array of 25 (5x5) electrodes. The array allows 64 individual tetrapolar measurements to be taken on 16 locations giving an impedance map of 49 mm² on the surface of a tissue sample. Multiple measurements at each location reduce the chance of anomalous results since these can later be identified and excluded. Preliminary results on bovine blood have shown good separation of the measured impedance between areas of different haematocrit and provided a visual representation of the surface impedance. Impedance maps have been obtained for a range of haematocrit between 0 - 80%.