of images." The prospects of using this technique for this indication will depend upon improved signal processing or recording. A study reported in June 2011 that Functional Electrical Impedance Tomography by Evoke Response (fEITER) has been used to image changes in brain activity after injection of an anaesthetic. One of the benefits of the technique is that the equipment required is small enough and easy enough to transport so that it can be used for monitoring depth of anesthesia in operating theatres. Perfusion (td-EIT) Due to its relatively high conductivity, blood may be used for functional imaging of perfusion in tissues and organs characterized by lower conductivities, e.g. to visualize regional lung perfusion. Background of this approach is that pulsatile tissue impedance changes according to differences in the filling of blood vessels between systole and diastole, particularly when injecting saline as contrasting agent. Sports medicine / home care (a-EIT, td-EIT) Electrical impedance measurements may also be used to calculate abstract parameters, i.e. nonvisual information. Recent advances in EIT technology as well as the lower number of electrodes required for recording global instead of regional parameters in healthy individuals can be used for non-invasive determination of e.g. VO2 or arterial blood pressure in sports medicine or home care. Commercial systems a-EIT and td-EIT Even though medical EIT systems had not been used broadly until recently, several medical equipment manufacturers have been supplying commercial versions of lung imaging systems developed by university research groups. The first such system is produced by Maltron International who distribute the Sheffield Mark 3.5 system with 16 electrodes. Similar systems are the Goe MF II system developed by the University of Göttingen, Germany and distributed through CareFusion (16 electrodes) as well as the Enlight 1800 developed at the University of São Paulo School of Medicine and the Polytechnic Institute of the University of São Paulo, Brazil which is distributed by Timpel SA (32 electrodes). These systems typically comply with medical safety legislation and have been primarily employed by clinical research groups in hospitals, most of them in critical care. The first EIT device for lung function monitoring designed for everyday clinical use in the critical care environment has been made available by Dräger Medical in 2011 – the PulmoVista® 500 (16-electrode system). Another commercial EIT system designed for monitoring lung function in the ICU setting is based on 32 active electrodes and was first presented at 2013's