Wells, Michael L

Abstract Background The evaluation of gastrointestinal (GI) bleeding is frequently negative despite a prolonged workup involving several different radiologic and endoscopic tests. Ferumoxytol, a superparamagnetic iron oxide agent used for treatment of iron deficiency anemia, can be used off-label as a blood pool contrast agent at MRI. Purpose To perform a proof-of-concept study to determine if ferumoxytol-enhanced MRI (FeMRI) can be performed to assist in detecting the presence and location of GI bleeding in patients who have undergone a negative standard evaluation. Methods A retrospective convenience cohort of patients examined with FeMRI at a single center over a 2-year period was evaluated. Inclusion criteria included clinical suspicion for slow or intermittent, active GI bleeding not localized following conventional testing. Exclusion criteria included any allergy to ferumoxytol or iron-containing agents, additional MRI scans scheduled within the following 72 hours, current pregnancy or breastfeeding, history of medication-related hypotensive episodes not related to an acute illness, syncopal events, arrhythmia, or low resting blood pressure. The patient’s clinical characteristics, examination results, and outcome during their hospital stay were examined. Results Five males and 1 female with average age of 66 years (range, 37-79 years) were imaged with FeMRI. All had undergone full diagnostic evaluation of the GI tract including upper and lower endoscopy and small bowel evaluation with imaging and/or endoscopic testing; in all patients, repeated rounds of testing were performed. Diagnostic images were obtained in all patients who underwent FeMRI. In 4/6 (67%) patients, FeMRI demonstrated active bleeding in the small bowel (n = 3) and colon (n = 1). Conclusion FeMRI was able to demonstrate the presence and location of active GI bleeding in hospitalized patients with previous extensive negative evaluation. FeMRI should be further evaluated to determine its performance characteristics as an examination in evaluating patients with GI bleeding.

Encompassing a broad spectrum of abnormalities from diffuse liver disorders to focal liver lesions, hypointense findings on hepatobiliary phase MR images offer valuable diagnostic information, provide insight on the functional status of the liver, and aid in characterization of other imaging features.