Approximately 5% of gastrointestinal bleeding presentations are due to suspected small bowel bleeding or obscure gastrointestinal bleeding (OGIB). Small bowel capsule endoscopy (SBCE) and CT/MR enterography are common modalities used to evaluate the small bowel for possible lesions. The miss rate of SBCE for small bowel tumors has been reported as high as 25%. Due to a concern for possible missed small bowel lesion, CTE/MRE is often performed after SBCE in patients with obscure GI bleeding, however the diagnostic yield of these studies is unknown. The primary aim of this study was to investigate the diagnostic yield of CTE/MRE performed after SBCE in patients with obscure GI bleeding.
A retrospective chart review was performed of patients who underwent both SBCE and CT or MR enterography for evaluation of obscure GI bleeding – both occult and overt. The capsule endoscopy database at a single tertiary academic medical center was reviewed for studies performed from 1/2010-4/2019. Only cases with clinical suspicion of small bowel bleeding were included. Charts were reviewed to determine whether patients had a subsequent CT or MR enterography. Exclusion criteria included more than 6 months between SBCE and enterography, incomplete SBCE and IBD diagnosis. Descriptive statistics were performed.
A total of n = 11 were included. The indications of the studies were evaluation of anemia and occult blood loss in the setting of unrevealing endoscopies in 72.7% of patients and evaluation of overt bleeding without source on endoscopy for 22.3% of patients. There were five (45.5%) significant small bowel findings on SBCE. There were no small bowel lesions identified by enterography. In the patients with overt bleeding, SBCE identified possible culprit lesions in 66.7% of patients and enterography didn't show any culprit lesions. In patients with occult blood loss, SBCE identified potential culprit lesions in 50% of the patients, while enterography didn't identify any. All patients with a negative SBCE also had a negative enterography study.
These findings suggest that there may be no additional diagnostic yield from enterography performed after SBCE in patients with suspicion of GI bleeding from a small bowel source. SBCE seems to have a high negative predictive value for significant small bowel lesions. Larger studies need to be performed to evaluate the utility of performing enterography after SBCE in the evaluation of suspected small bowel bleeding, both occult and overt.