Electrical impedance tomography; the construction and application to physiological measurement of electrical impedance images.

Electrical impedance tomography enables images of tissue resistivity to be produced from measurements made via an array of surface electrodes. Using the technique of Applied Potential Tomography (APT) an array of 16 electrodes placed around the trunk has been used to image gastric, respiratory and cardiac related events. Some of the advantages and disadvantages of the technique are considered and the possibility of improvement discussed. Some cardiac gated images are presented which show the movement of blood on systole so allowing cardiac output and lung perfusion to be displayed.