Gastric emptying of liquid meals. A study in 88 normal persons.

Using a gamma camera, gastric emptying of a nutrient liquid meal labelled with 99m-Tc-DTPA has been studied in 88 normal subjects in order to assess reproducibility and to establish the range for gastric emptying under standardized conditions. The emptying patterns were visualized as time-activity curves. The early phase (0-15 min) was characterized by a rapid emptying taking place during the first minutes and a subsequent period of almost no emptying (plateau) lasting for up to 20 minutes, followed by an almost constant emptying in the later phase (15-60 min). In the early and later phase mean percentages emptied were 13% (range, 0-30) and 49% (range, 9-79), respectively. The intraindividual variation was larger for repeated tests of months' than of days' intervals, the coefficients of variation in the early phase being on the average 72% (range, 29-175) and 37% (range, 13-128), respectively. During the later phase less variation was seen. Irregular deviations from the standard pattern were observed in the curves, indicating gastric contractions and duodenogastric reflux. Serial scintifotos revealed that the radionuclide labelled gastric content was not uniformly distributed within the stomach. This activity distribution, affected by the subject's position during emptying, seemed to occur instantaneously and to be completed within a few minutes. These findings allow the standardized radioisotope technique to be used for physiological, pathophysiological and pharmacological studies, when performing consecutive studies in the same individual within days or a few weeks. The wide reference interval for gastric emptying of this liquid meal invalidates the method as a clinical diagnostic tool.