Measurement of gastric emptying rates by radioactive isotope scanning and epigastric impedance.

When liquids of low electrical conductivity enter the stomach the impedance of the epigastric region to a 4 mA, 100 kHz current increases. There follows a decline, which logically represents gastric emptying. This method of measuring gastric emptying was compared against scintigraphy in six volunteers, and similar results were obtained. Impedance monitoring is entirely noninvasive, inexpensive, simple, and quick. The method merits further exploration.