THE [C-13]ACETATE BREATH TEST ACCURATELY REFLECTS GASTRIC-EMPTYING OF LIQUIDS IN BOTH LIQUID AND SEMISOLID TEST MEALS

Background/Aims: The current standard for gastric emptying studies are radioactive isotope methods. [C-13]breath tests have been developed as a nonradioactive alternative. the aim of this study was to validate a [C-13]acetate breath test as a measure of gastric emptying of the liquid phase both in liquid and semisolid test meals by simultaneous radioscintigraphy. Methods: Thirty-five patients with dyspeptic symptoms and 20 healthy volunteers were tested using a semisolid oatmeal or a liquid test meal. Both test meats were labeled by 150 mg sodium [C-13]acetate and (in patients) by 45 MBq Tc-99m-albumin colloid. Half-time of gastric emptying was calculated after curve fitting of the C-13 exhalation to a modified power exponential function. Tc-99m-albumin emptying was measured by conventional radioscintigraphy. Results:The half-emp tying times for the [C-13]acetate breath test closely correlated to those measured by radioscintigraphy both for semisolids (r = 0.87) and liquids (r = 0.95). The time of maximum (CO2)-C-13 exhalation was itself a reliable parameter compared with the half-emptying times obtained by scintigraphy (r = 0.85 for semisolids; r = 0.94 for liquids). Conclusions: The [C-13]acetate breath test is a reliable and noninvasive tool for the analysis of gastric emptying rates of liquid phases without radiation exposure.