Approach to compensate measurement errors in electrical impedance tomography

Electrical Impedance Tomography (EIT) is an imaging modality to visualize conductivity changes inside the human body. By injecting small alternating currents, the resulting surface potentials can be acquired. This bio-impedance measurement chain usually includes multiplexer, cables and electrodes. Due to the inherent resistances and parasitic capacitance of the components, the acquired signal is always afflicted with errors. Commonly used EIT systems have problems to provide a sufficient accuracy for absolute measurements in the frequency range above 100 kHz. Therefore, we developed a measurement scheme to correct the resulting signals with the help of reference measurements.