99mTc pertechnetate scintigraphy and premedication for the search for ectopic gastric mucosa in Meckel's diverticulum.

BACKGROUND: Meckel's diverticulum (MD) is the most common anomaly of the large intestinal tract (1-3%) and is more frequent in children (62% < 2 years) and in males (66%). It often involves ectopic gastric mucosa which manifests through gastrointestinal bleeding in 50% of cases. 99m-Technetium scintigraphy (99mTcO4) is one of the procedures available for the non-invasive diagnosis of ectopic gastric mucosa. METHODS: Twenty-eight patients (11 females, 17 males), including 16 children and 12 adults, aged 8 months-80 years old, were included in the study. The patients were admitted to hospital for hematochezia and melena (22) associated with abdominal pain (5): 3 patients repeatedly presented occult blood in their stools. Two patients only suffered from abdominal cramps and one only anemia. Patients were studied using plain abdominal radiographs and ultrasound; 10 underwent gastroscopy and colonoscopy; radiological contrast studies were performed in 5 patients. All tests were inconclusive. All the patients were premedicated with oral cimetidine (20 mg/kg in pediatric patients and 300 mg q.i.d. for adults, 48 hours before the test) or with ranitidine i.v. (1 mg/kg, max 50 mg, in 20 minutes, one hour before the test); barium meals and colonoscopy were deferred for 2-3 days after examination. An intravenous injection of 37-180 Mbq of 99mTcO4 was given followed by a dynamic study of the abdomen in anterior projection. Images were acquired for one hour or until the visualisation of abnormal foci of intake: in this case, lateral and oblique images were acquired for a better localisation of the suspicious area. Some patients were administered furosemide i.v. (0.75 mg/kg). All underwent a follow-up period of 12 months. RESULTS: Pertechnetate scintigraphy was positive in 10 cases and the presence of ectopic gastric mucosa was confirmed by surgery. The study was negative in 18 cases: 3 of them were discharged with a diagnosis of Salmonella infection, polyp of the small bowel or ulcer of the large bowel respectively; the other 15 patients did not show symptoms of onset during follow-up. CONCLUSIONS: These results confirm the high diagnostic accuracy of pertechnetate scintigraphy to detect ectopic gastric mucosa if associated with H2-receptor-blocking agent premedication.