Correcting electrode modelling errors in EIT on realistic 3D head models. (26th October 2015)

• Record Type: Journal Article
• Authors: Jehl, Markus; Avery, James; Malone, Emma; Holder, David; Betcke, Timo
• Is Part Of: Physiological measurement. Volume 36:Number 12(2015:Dec.)
• Page Start: 2423
• Page End: 2442
• Publication Date: 2015-10-26
• Subjects: electrical impedance tomography -- image reconstruction -- electrode error correction -- modelling errors; Physiology -- Measurement -- Periodicals; Patient monitoring -- Periodicals; 612
• DOI: 10.1088/0967-3334/36/12/2423
• Languages: English
• ISSNs: 0967-3334

Abstract

Abstract: Electrical impedance tomography (EIT) is a promising medical imaging technique which could aid differentiation of haemorrhagic from ischaemic stroke in an ambulance. One challenge in EIT is the ill-posed nature of the image reconstruction, i.e. that small measurement or modelling errors can result in large image artefacts. It is therefore important that reconstruction algorithms are improved with regard to stability to modelling errors. We identify that wrongly modelled electrode positions constitute one of the biggest sources of image artefacts in head EIT. Therefore, the use of the Fréchet derivative on the electrode boundaries in a realistic three-dimensional head model is investigated, in order to reconstruct electrode movements simultaneously to conductivity changes. We show a fast implementation and analyse the performance of electrode position reconstructions in time-difference and absolute imaging for simulated and experimental voltages. Reconstructing the electrode positions and conductivities simultaneously increased the image quality significantly in the presence of electrode movement.