THE TWO major categories of contrast agents currently used to opacify the lumen of the gastrointestinal (GI) tract are barium sulfate suspensions and the iodinated water-soluble materials. Despite an extensive experience with these contrast media in the GI tract, confusion remains over their proper utilization. This article reviews the indications, uses, and risks of the commonly employed GI contrast agents.
Barium Sulfate Suspensions
Barium sulfate is almost totally inert within the GI tract, having little physiological effect other than responses to volume and fluidity.1 Many commercial barium products are available for examining the GI tract; they vary widely in regard to density, viscosity, and ability to coat the mucosal surface. Many barium products have wide application throughout the GI tract, while others are specifically formulated for more limited use, such as double-contrast examination of the stomach or colon.Under most circumstances, barium sulfate suspensions are the preferred contrast materials