Quantitation and the elimination of errors in bile reflux tests using a gamma camera

Entero-gastric reflux may be assessed quantitatively using 99mTc HIDA and a gamma camera. We have devised a computer program which applies corrections for several sources of error. The technique was validated using naso-gastric aspiration and phantom experiments. In 23 patient studies, 13 patients considered not to show reflux by visual assessment had a mean percentage injected dose (PID) in the stomach of 1.9% before correction and less than 1% after correction. The 10 patients with reflux showed a fall of PID from 5.8% to 1.7% as a result of the correction. In 14 patients the mean PID in the stomach after computer correction (3%) was not significantly different from that (3.5%) measured by aspiration. Computer correction of bile reflux data is essential when attempting to quantify the amount of entero-gastric reflux using a gamma camera.