The clinical value of ferric ammonium citrate: a positive oral contrast agent for T1-weighted MR imaging of the upper abdomen.

This study was undertaken to determine whether ferric ammonium citrate (FAC), a positive magnetic resonance (MR) contrast agent, is of clinical value in demonstrating or excluding pathology of the upper gastrointestinal tract. A retrospective review was performed of pre- and post-FAC studies of MR examinations in 203 patients from phase II and III clinical trials in whom final diagnoses had been established based on the results of biopsy, surgery, or independent imaging procedures. Two independent reviewers made randomized and blinded assessments of the stomach, duodenum, and pancreas. FAC significantly increased the certainty of diagnosis for normal studies of the stomach and duodenum for both readers (P < 0.001) and for abnormal studies of the stomach for one reader (P = 0.004). FAC also significantly increased the certainty of diagnosis for normal pancreas for one reader (P < 0.001). FAC significantly (P < 0.001) increased accuracy and specificity for diagnoses involving the stomach and duodenum for both readers and for one reader for the pancreas. There was significant improvement in sensitivity for gastric diagnoses (P = 0.013) for one reader but not for the duodenum or pancreas. We conclude that FAC is helpful in demonstrating and excluding upper gastrointestinal pathology on MR.