The initial phase of gastric emptying before and after vagotomy and pyloroplasty.

The initial phase of gastric emptying of solid food was monitored with the use of a gamma camera and on-line computer facilities. In normal subjects a consistent pattern was seen comprising an early delay in the onset of emptying ("plateau"), followed by an exponential decay curve. After vagotomy the plateau was lost, and the exponential pattern of emptying commenced once the stomach was full. There was no evidence of sudden "dumping" of contents from the stomach. The overall rates of emptying as measured by the half emptying time (T 1/2) were the same in normal and postvagotomy subjects.