Evaluation of human postprandial antral motor function using ultrasound.

We used high-resolution ultrasound to characterize postprandial antral excursion characteristics in 15 healthy volunteers. Antral circumference was repeatedly measured in the sagittal plane anterior to the abdominal aorta, at 15-min intervals following ingestion of a standard meal. At each recording period, the maximal and minimal antral circumference was noted. In seven volunteers, antral circumference was studied continuously for 5 min at each 15-min recording period to assess the frequency and regularity of antral excursions. Antral circumference increased immediately after meal ingestion from preprandial values of 64 +/- 2.6 (means +/- SE) to 138 +/- 3.1 mm and then gradually decreased with meal emptying to 72 +/- 2.6 mm at 90 min. The continuous recordings of antral images revealed that antral circumference transiently decreased at regular intervals; the interval between successive excursions was 20.1 +/- 0.2 s. There was no change in the excursion interval with emptying. The excursion amplitude decreased from 33 +/- 3.9 mm immediately post-meal ingestion to 13 +/- 1.5 mm at 90 min (r2 = 0.62 +/- 0.07). The ratio between the excursion amplitude and circumference of the relaxed antrum changed only slightly with time (slope = 0.0009 +/- 0.00003). Comparison of repeat studies in 10 volunteers showed a low intra-individual variation for postprandial antral circumference and excursion amplitude.