Methods of cardiac gating applied potential tomography.

Electrical impedance imaging of the heart, pulmonary perfusion and the great blood vessels can only be achieved by synchronising the data collection with cardiac activity. Due to low signal-to-noise ratio, temporal averaging is needed to improve the image quality. In this study several methods of ECG gating are attempted to synchronise the applied potential tomography (APT) serial data collection with the cardiac cycle. They allow us to collect sequential images time-locked with the R-wave of the patient, and hence image the pulsatile movement of blood. Different methods are examined for their sampling speeds, noise levels and ability to image before systole. A method of image data rearrangement in order to provide an apparent increase in speed is also discussed.