Compensating Spatial Variability of Quantity Index in 2D Electrical Impedance Tomography: COMSOL Multiphysics Study

S. Oh, and R. Sadleir
Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA

In Electrical Impedance Tomography (EIT), an array of surface electrodes is used to inject current and measure the resulting voltages to non-invasively obtain conductivity distributions of objects. The system can be easily implemented as a device that monitors hemorrhage, respiration, gastric emptying or brain activities.

The Quantity Index (QI), an integral measure of reconstructed images, can be used for quantitative observation of physiological changes in real-time. However, the distribution of QI is generally not uniform over the image plane, which can lead to large errors in estimating anomaly volumes.

Here, COMSOL Multiphysics was used to explore QI’s spatial variability. We then designed a novel method that compensates the spatial variability with the ‘ideal’ characteristics of QI. Our method was tested with data from COMSOL models and phantom experiments, which showed a great reduction of errors due to spatial variability of QI.