4927624 Clay magnetic resonance contrast agents for gastrointestinal comsumption or introduction

Contrast medium compositions for delineation of bowel during magnetic resonance imaging (MRI) of the abdomen are provided for oral or rectal administration. The compositions consist of aqueous suspensions of clay in finely-divided particles which expose a large surface area to the suspending water and impose a condition of dynamic anisotropy upon the adjacent water, resulting in reduction predominantly in the transverse relaxation time of the water and subsequent loss of signal from the bowel lumen.