Scintigraphic evaluation of enterogastric reflux using 75Se-HCAT: methodology and first clinical observations

The aim of this study was to assess the possibility of detecting enterogastric reflux (EGR) by 75Se-HCAT cholescintigraphy. The lowest detectable activity in the gastric area at different concentrations of the radiotracer in the gallbladder was preliminary measured both in a plastic phantom and in an in vivo model. Ten patients were studied after a single oral administration of 1480 KBq 75Se-HCAT. Gamma camera imaging was carried out for five consecutive days during both fasting and after meal ingestion. In our in vivo model an EGR corresponding to 1% of gallbladder content on day one and 8% on day five was detected. In three out of five patients in whom bile was present in the stomach at endoscopy, 75Se-HCAT cholescintigraphy demonstrated an EGR, while in three out of five patients in whom endoscopy was negative, 75Se-HCAT cholescintigraphy detected EGR either during fasting or after meal ingestion. As EGR is not constant, 75Se-HCAT may be a useful tracer of bile to detect EGR over a prolonged period of time and in different physiological conditions.