Role of MRI for assessment of GI bleeding: a pictorial review of indications, technique and performance.

The evaluation of patients with gastrointestinal (GI) bleeding is complicated due to the variety of tests available and the large number of potential causes of bleeding. MRI is less commonly used than computed tomography and endoscopy but it can diagnose disease that causes GI bleeding and serve as a complementary role to other tests. MRI is most often used in the form of magnetic resonance enterography (MRE) to assess patients with suspected bleeding from the small bowel. While CT enterography (CTE) and video capsule endoscopy (VCE) are the more commonly used tests in the setting of GI Bleeding, MRE has characteristics which may make it the more favorable modality for a given patient. Potential advantages of MRE, protocol considerations and the literature delineating its diagnostic performance for detecting pathology which can cause GI bleeding relative to CTE and VCE are reviewed here. MRI is uncommonly used to assess patients with upper GI bleeding, lower GI bleeding and patients with bleeding sites that remain undetected despite a formal evaluation of the GI tract, however it may add value in specific clinical scenarios. These uncommon scenarios and specific clinical examples are also presented to highlight the potential benefits of MRI.