Gastric clearance of radiopaque markers in the evaluation of gastric emptying rate

Background: The study of gastric emptying rate of solids using radiopaque indigestible solid markers has been a poorly employed technique because some kinds of markers do not leave the stomach at the same time as the meal but during the interdigestive migrating motor complex (IMMC). The aim of this study was to evaluate whether markers of particular shape and size can be successfully employed for this purpose. Methods: Twenty-eight non-ulcer dyspeptic (NUD) patients and 20 healthy volunteers received a standard solid meal (790 Kcal) together with 20 small polyethylene radiopaque cylinders (5 mm × 2 mm in diameter). Gastric emptying rate was evaluated by ultrasound while the emptying of markers was simultaneously followed by X-rays using a brilliance intensifier. Results: Final emptying time (FET = time when the antrum area returns to fasting size) of digestible solids was 355 ± 35 min in NUD patients versus 265 ± 20 min in controls (P < 0.001). The gastric emptying curve of digestible solids correlated with emptying of markers both in NUD patients (r = +0.96) and in controls (r = +0.93). Conclusions: The assessment of gastric clearance of radiopaque cylinders of 2 mm × 5 mm in size is a reliable tool for the study of gastric emptying rate of digestible solids. This is a readily available and easily performed test in any radiology unit.