EVALUATION OF ORAL CONTRAST AGENTS FOR ABDOMINAL MAGNETIC-RESONANCE-IMAGING

We evaluated the efficacy of sis available oral contrast agents in imp roving visualization of bou el and surrounding structures on magnetic resonance imaging of the abdomen and pelvis. Five volunteers were exam ined without oral contrast (baseline) and, on separate occasions, afte r ingestion of 600-900 cc of two positive contrasts [12.5% weight-to-v olume (w/v) corn oil emulsion (COE), Redi Cat (EZ-Em Corp., Westbury, NY) mixed with 1% ferric ammonium citrate (FAC)] and four negative con trasts [220%, 105%, 85%, 60% w/v barium sulfate (Liquid HD, Liquid Pol ybar Plus, HD 85, reconstituted EZ Fake; EZ-Em Corp., Westbury, NY)]. Spin-echo axial and coronal T-1-weighted and axial T-2-weighted images were obtained in the abdomen and pelvis. Three radiologists blindly g raded the images for improved visualization of bowel and surrounding s tructures, Data were analyzed for statistical significance using the G eneral Linear Models algorithm. In the upper abdomen (stomach, duodenu m, liver, and pancreas), COE yielded the highest mean scores (p <.0001 ), followed by 220% w/v barium. For the lower abdomen (ileum, colon), 220% w/v barium yielded the highest scores(p <.0001) and COE was much worse. The higher density barium preparations (220% and 105% w/v) yiel ded higher scores than their lower density counterparts (85% and 60%). All contrasts improved visualization of the retroperitoneum and splee n, but no one agent was best. All agents tested are superior to no age nt at all. For visualization of the upper abdomen, 12.5% COE performed best. For visualization of the lower abdomen, 220% w/v barium perform ed best. For concurrent evaluation of both areas with one agent, 220% w/v barium performed best.