University of Rostock

The Electroimpedance Tomography (EIT) is a non invasive imaging technology. It is based on measurement of local differences in the electrical conductance within the object under investigation.

To accomplish this, a series of electrodes is placed around the region of interest. A low amplitude alternating current is injected between a pair of electrodes while the resulting potential is measurement by the remaining electrode pairs. The measurement cycle is continued by repeating the measurement over different injection electrode pairs. Afterwards, a cross section image can be reconstructed from the set of measurements.

The primary focus of EIT applications is in the field of medicine. Currently, there are challenges towards spatial resolution remaining in comparison to established imaging technologies like CT or MRT. On the other hand, EIT provides a relatively high temporal resolution in a range of typically 50 Hz. Another advantage of EIT is the portability of the equipment which enables long term observation as well as critical care applications.

Previously, the primary area of interest for EIT was the observation of lung ventilation. Lung tissue exhibits a conductivity several times higher than the surrounding tissue which results in good contrast within the reconstructed images. Consequently, clinical questions concerning ventilation were among the first topics being researched. Recent areas of interest include heart activity and perfusion.