Gastric gas and fluid emptying assessed by magnetic resonance imaging

Magnetic resonance imaging (MRT) was used to characterize the volumes and r ates of gastric emptying of both liquid and gas following the ingestion of beverages of varying carbonation and carbohydrate levels. Eight subjects dr ank 800 mi each of four test beverages in a counterbalanced order: water, a non-carbonated carbohydrate-electrolyte solution (NC), a lightly carbonate d carbohydrate-electrolyte solution (PC), and a carbonated cola (CC). T2-we ighted, echoplanar images (25-30 contiguous slices, 1 cm thick, 256 x 128 m atrix, TE = 80, 40 cm FOV) of the abdomen were collected at minutes 3.110, 20, 30, 45. and 60 following beverage ingestion. Images were analyzed for g as and liquid volumes. Water and NC emptied the most rapidly, with half tim es of 21(3) and 31(3) min. respectively [mean (SE)]. PC emptied significant ly slower [47 (6) min] and CC slower yet [107 (8) min]. The carbonation con tent of the beverage accounted for 84% of the variation in emptying time. w hereas carbohydrate content did not account for any significant variation. The gastric gas volume of the CC was higher at 2 min post-ingestion compare d with all other drinks; however, the rate of emptying of the gas was the s ame among all beverages. Significantly greater total gastric volumes (gas liquid) were associated with the ingestion of CC, and accordingly produced a greater severity of gastric distress, as evaluated with a gastric distre ss inventory. The high gastric gas volumes (approximate to 600 ml) after in gestion of CC suggested a potential sourer of error in body composition usi ng standard hydrostatic weighing methods. This prediction was tested in nin e additional subjects. Ingestion of 800 mi of CC prior to hydrostatic weigh ing resulted in a 0.7% underestimate of body density and thus an 11% overes timate of percentage body fat compared to measurements made before beverage consumption.