Comparison of applied potential tomography and impedance epigastrography as methods of measuring gastric emptying

Two new non-invasive methods of measuring gastric emptying, impedance epigastrography (IE) and applied potential tomography (APT) have been compared. Measurements in vitro showed that there is a good correlation between the square of the radius of a glass rod placed in the centre of a tank and values obtained by IE or APT. However, if the rod is moved anteriorly in the tank IE values increase markedly, whereas APT values are unchanged. Both APT and IE can be used to follow gastric emptying of liquid meals; however, the results obtained using APT are more reproducible and have a better correlation with those obtained simultaneously by scintigraphy. Neither method was able accurately to follow gastric emptying unless gastric acid secretion was inhibited by cimetidine.