RESUMEN
Background: 99mTc red blood cell scintigraphy is a non invasive diagnostic method for low flow gastrointestinal bleeding. Aim: To assess the diagnostic yield of this method in patients admitted with gastrointestinal bleeding in whom upper gastrointestinal endoscopy was negative. Patients and methods: The clinical records of 59 patients, aged 6 to 90 years old (35 male), with active gastrointestinal bleeding subjected to a 99mTc red blood cell scintigraphy were reviewed. All had non diagnostic upper gastrointestinal endoscopic studies, and in 20 a selective arteriography was performed. Results: In 40 patients the scintigraphy was positive for gastrointestinal bleeding, and in 57 percent of these the exam was positive during the first hour. Fifteen of the 19 patients with a negative scintigraphy did not have an active clinical bleeding at the moment of the examination. In 24 patients, a final ethiological diagnosis was reached. In 93 percent of these patients scintigraphy correctly identified the bleeding site. In one patient with a negative scintigraphy, angiography disclosed a pseudo aneurysm of the splenic artery that was not bleeding actively. Conclusions: In these patients with negative upper gastrointestinal endoscopy 99mTc red blood cell scintigraphy had a 91 percent sensitivity for the diagnosis of active gastrointestinal bleeding