Quantification of distal antral contractile motility in healthy human stomach with magnetic resonance imaging

Purpose: To quantify healthy postprandial: 1) propagation, periodicity, geometry, and percentage occlusion by distal antral contraction waves (ACWs); and 2) changes in ACW activity in relationship to gastric emptying (GE). Materials and Methods: Using 1.5-T MR scanner, nine healthy fasted volunteers were examined in the right decubitus position after ingestion of 500 mL of 10% glucose (200 kcal) with 500 mu M Gd-DOTA. Total gastric (TGV) and meal volumes (MV) were assessed every five minutes for 90 minutes, in and interspersed with dynamic scan sequences (duration: 2.78 minutes) providing detailed images of distal ACWs. Results: TGV increased by 738 +/- 38 mL after ingestion (t(0)), subsequently decreasing in parallel to GE. The mean GE rate and half-emptying time were 24 +/- 3 mL/5 minutes and 71 +/- 6 minutes, respectively. Accompanying ACWs reached a periodicity of 23 +/- 2 seconds at t(35) and propagated at an unvarying speed of 0.27 +/- 0.01 cm/second. Their amplitude of 0.70 +/- 0.08 cm was constant, but the width decreased along the antral wall by 6 +/- 2%/cm (P = 0.003). ACWs were nonocclusive (percentage occlusion 58.1 +/- 5.9%, to at the pylorus) With a reduction in occlusion away from the pylorus (P < 0.001). No propagation and geometry characteristics of ACWs correlated with the changes of MV (mL/5 minutes; R-2 < 0.05). Conclusion: Our results indicate that ACWs are not imperative for emptying of liquids. This study provides a detailed quantitative reference for MRI inquiries into pharmacologically- and pathologically-altered gastric motility.