COMBINED CARBON-13-GLYCINE CARBON-14-OCTANOIC ACID BREATH TEST TO MONITOR GASTRIC-EMPTYING RATES OF LIQUIDS AND SOLIDS

The aim of the present study was to develop a dual-carbon-labeled brea th test for simultaneously measuring gastric emptying rates of liquids and solids with significantly less radiation burden to the patient th an the radioscintigraphic technique. Methods: A test meal was used in which the liquid phase was labeled with two markers, i.e., 3.7 MBq of (111)ln-DTPA and 100 mg of C-13-glycine; the solid phase also was dual ly labeled with 110 MBq of Tc-99m-albumin colloid and 74 kBq of C-14-o ctanoic acid. Simultaneous radioscintigraphic and breath-test measurem ents were performed in 27 subjects, 10 normal controls and 17 patients with dyspeptic symptoms. Mathematic analysis of the excretion rate of labeled CO2 allowed the definition of four parameters, i.e., the gast ric emptying coefficient, the gastric half-emptying time, the peak exc retion time and the lag phase. Results: There was a good to excellent correlation between the gastric emptying coefficient and the scintigra phic half-emptying time (r = 0.74 for liquids and r = 0.88 for solids) , between the half-emptying time determined by breath test and the sci ntigraphic half-emptying time (r = 0.91 for liquids and r = 0.92 for s olids), between the peak excretion time and the scintigraphic half-emp tying time (r = 0.91 for liquids and r = 0.96 for solids) and between the lag phase of solid emptying determined by both techniques (r = 0.8 9). Conclusion: The dual carbon-labeled breath test is a valid, minima lly invasive technique to measure the gastric emptying rate of both li quids and solids.