Gastrointestinal Motility, Part 1: Esophageal Transit and Gastric Emptying

Normal global esophageal emptying (multiple swallows). Sequential images at 15 s per image are shown (left). Region of interest (rectangular box) is drawn over entire esophagus. From this region, time–activity curve (right) is generated showing percentage of activity retained in esophagus at each time. Amount of activity retained after multiple swallows can be used to help characterize primary esophageal motor disorders (Fig. 3; Table 1) or to follow therapeutic interventions as in achalasia.

Esophageal emptying for primary esophageal motility disorders. Mean data for healthy subjects are shown compared with diffuse esophageal spasm (DES), achalasia, and scleroderma. Emptying curve for patients with esophagitis from gastroesophageal reflux is similar to DES. (Adapted from (75).)

Multiple factors associated with GE are considered important to explain dyspeptic patient symptoms. Total GE, impaired fundal accommodation, and visceral hypersensitivity are 3 major factors currently under study. Antral–duodenal coordination and duodenal–gastric feedback mechanisms are also considered important but are not as well characterized. (Modified from (76).)

Normal dual-isotope, solid–liquid GE study (anterior views only). These images demonstrate early rapid distribution of liquids throughout stomach at 0 min. Liquid emptying curve is monoexponential. In contrast, solids show preferential early fundal localization (accommodation) (double arrows). Over time, solids progress down into antrum (triple arrows). Solid emptying curve is sigmoidal because of early lag phase for solids. Over time, one can observe small-bowel transit of solids and liquids, with buildup of activity in the terminal ileum (oval region of interest).