Evaluation of potential gastrointestinal contrast agents for echoplanar MR imaging

Although the diagnostic application of echoplanar imaging (EPI) has until now been limited, recent technical advances provide anatomic resolution and signal-to-noise ratios comparable to that of conventional MR imaging. The purpose of this study was to investigate approved aqueous gastrointestinal contrast agents for use in abdominal EPI. Conventional and echoplanar MR imaging experiments were performed with 1.0 Tesla whole body systems. Phantom measurements of Gastrografin, barium sulfate suspension, oral gadopentetate dimeglumine, water, and saline were performed. Signal intensity (SI) of aqueous oral barium sulfate and iodine based CT contrast agents was lower on conventional spin-echo (SE), Flash, and Turbo-Flash images than on EP images. The contrast agents exhibited higher SI on T2-weighted SE PE images and TI-time dependence on inversion recovery EP-images. The barium sulfate suspension was administered in volunteers to obtain information about bowel lumen enhancement and susceptibility artifacts. Oral administration of the aqueous barium sulfate suspension increased bowel lumen signal and reduced susceptibility artifacts. Approved aqueous gastrointestinal contrast media or flavored saline with long relaxation times may serve as safe, simple, and effective gastrointestinal contrast agents in abdominal EPI.Correspondence to: P. Reimer