Possible Role of Meckel's Scan Fused with SPECT CT Imaging: Unraveling the Cause of Abdominal Pain and Obscure-Overt Gastrointestinal Bleeding

Abstract

A 27-year-old male presented with recurrent abdominal pain and high volume hematochezia despite undergoing extensive testing and a right hemicolectomy 3 years prior for a linear bleeding ulceration in the ascending colon. Studies at the University of Michigan included esophagogastroduodenoscopy (EGD), colonoscopy and video capsule endoscopy (VCE), revealing an arteriovenous malformation (AVM) in the terminal ileum. He was hospitalized for recurrent symptoms. His presentation suggested a small bowel source of obscure-overt GI bleeding based on prior non-diagnostic colonoscopy and EGD and a bilious nasogastric lavage. Tagged red blood cell scan localized bleeding to the right lower quadrant. Colonoscopy showed fresh blood in the terminal ileum without a clear source. Angiography showed no evidence of bleeding or terminal ileal AVM. A novel Meckel's scan fused with SPECT imaging showed focal uptake in the terminal ileum. The patient underwent Meckel's diverticulectomy with sparing of adjacent bowel and has remained asymptomatic for 19 months. This case illustrates that patients with obscure-overt GI bleeding require a step-wise multi-modality diagnostic work-up. Because Meckel's scans are false-positive in 28% of adults, Meckel's scan fused with SPECT imaging may offer an approach to refine diagnostic accuracy of either scan alone, but requires further investigation. Exploratory laparotomy should be reserved as a last option and is best performed with intraoperative endoscopy.

Keywords: Chronic abdominal pain; Meckel's diverticulum; Obscure-overt gastrointestinal bleeding.

Fig. 1

Video capsule endoscopy shows an AVM in the terminal ileum.

Fig. 2

Diagnosis of Meckel's diverticulum by imaging. a Meckel's scan was performed by administering 15 mCi of Tc-99m pertechnetate intravenously as a bolus. A coronal planar image shows one focus of intense tracer uptake in the left upper quadrant, corresponding to normal gastric uptake (S), and a second focus of intense uptake localizing to the right lower quadrant, suspicious for Meckel's diverticulum (M). b, c Meckel's scan images are fused with axial (b) and coronal (c) SPECT (single photon emission computed tomography) images to localize and define the abnormality responsible for the positive Meckel's scan. In the right lower quadrant near the colon (C) a focus of intense uptake localized to the terminal ileum, consistent with a Meckel's diverticulum (M).

Fig. 3

a Cross section of Meckel's diverticulum. b Low power microscopic examination of H&E stained specimen showing junction of ectopic gastric mucosa on the left (asterisk) with small intestinal mucosa on the right (arrow).