Evaluation of the use of ultrasonography in the study of liquid gastric emptying.

Gastric emptying of two different test liquid meals (500 ml isotonic saline and 500 ml skimmed milk, 1.8% fat) has been measured in 10 (saline) and in 19 (milk) normal volunteers by means of real-time ultrasonography (RUS) and scintigraphy, employed simultaneously. In each subject, saline and milk contained 37 MBq of diethylenetriaminopentacetic acid (DPTA) marked with 99mTc. Determinations were made thereafter every 5 min up to 45 min with saline and every 30 min up to a maximum of 220 min with milk. The determination of gastric emptying by RUS was obtained indirectly through the measurement of gastric dimensions, with a single scan performed at the epigastrium, while the subject was kept in a standing position. At each observation, the percent decrease of gastric measurements and the decay in radioactivity over the gastric region were calculated, blind, by two independent examiners. Linear regression and correlation coefficient were subsequently computed for gastric measurements and decay in radioactivity. The results show that the values obtained with RUS do not differ grossly from the ones obtained with scintigraphy. This suggests that the ultrasonographic determination of gastric dimensions with a single section of the stomach may be a valuable method for use in the evaluation of gastric emptying of liquids.