Scintigraphy of the small intestine: a simplified standard for study of transit with reference to normal values

Abstract.

Evaluation of small bowel transit, which should preferably be performed using non-invasive techniques, is complex owing to the anatomical position of the small bowel. In order to avoid any influence of the gastric emptying rate on scintigraphic results, we have used ^99mTc-HIDA, an intravenous tracer that is excreted in bile and thereby delivered directly into the duodenum. Thirty healthy subjects were studied after an overnight fast. Immediately after administration of 120 MBq ^99mTc-HIDA, dynamic 1-min image acquisitions were begun. The duodenum and caecum were easily identified on the digitised images. Small bowel transit time was determined from the difference in the arrival times of the radiopharmaceutical in the proximal duodenum and caecum, as assessed by evaluation of the count rate against background activity (Scint 1) and by the visual appearance of activity (Scint 2). Hydrogen breath test was performed simultaneously to evaluate scintigraphic transit. Scintigraphic transit tests were also performed in 23 patients with motility disorders who had undergone manometry of the small bowel. In healthy subjects, the transit time of ^99mTc-HIDA was 77.9±31.1 min (Scint 1) or 79.3±30.9 min (Scint 2) and the lactulose transit time was 100.1±43.4 min. Seventeen of the 23 patients had a dysmotility pattern verified by manometry, and in 14 of these patients, ^99mTc-HIDA transit was prolonged. ^99mTc-HIDA small bowel transit is a readily available method for the detection of transit abnormalities in the clinical setting. The method is clinically feasible and the transit time of ^99mTc-HIDA shows a good correlation with results of the hydrogen breath test (lactulose transit time) in healthy volunteers.