Scintigraphic assessment of interdigestive duodenogastric reflux in humans: Distinguishing between duodenal and biliary reflux material

Background: Late duodenal phase III is characterized by retroperistalsis. T he physiologic function of this phenomenon is unknown. Our aim was to study the relationship between duodenal motility and the transport of duodenal c ontents from the biliary tract and the duodenum by using a double-isotope t echnique. Methods: Manometric analysis of the direction of interdigestive d uodenal pressure waves was performed in 12 volunteers. Duodenal marker was infused directly into the proximal duodenum, and bile marker was infused in travenously for 2 h. Radionuclide activity was examined for regions corresp onding to the stomach, gallbladder, and duodenum. Results: In phase III ant egrade pressure waves dominated with propulsion of both markers to the jeju num. Retroperistalsis occurred in 90% of the activity fronts, and was alway s (100%) followed by retropulsion of duodenal marker to the stomach. A clea r-cut reflux of bile marker was seen in only 17% of the activity fronts. Th e incidence rate of duodenogastric reflux was highest in phase III (P = 0.0 08) compared with phase II with an infrequent (P = 0.003) admixture of bile . Bile marker contents increased abruptly in the gallbladder during phase I II. conclusions: Late phase III acts as a retroperistaltic pump, retropelli ng duodenal contents to the stomach. In this physiologic duodenogastric ref lux. bile is avoided by deviation to the gallbladder, probably by a phase I II-associated occlusion of the sphincter Oddi.