Present approaches to barium mixtures: esophagus, stomach, small bowel, colon

Barium sulfate suspensions have been used for many decades as contrast agents for the gastrointestinal (GI) tract. They are directly affected by particle size, ionic charge, suspending agents, and the osmotic properties of the suspension. Because barium sulfate is such a strong absorbing substance, suspending agents are needed to prevent adsorption of air, water, or substances encountered in the GI tract. Flocculation of barium suspensions by the action of mucin is an especially difficult problem, but agents such as carboxymethylcellulose have substantially reduced the incidence of such changes. In general, the double-contrast examination, whether of the esophagus, stomach, small bowel, or colon, requires a dense, fluid barium which coats well and which maintains a smooth uniform film on the mucosal surface for a reasonable period of time under physiologic conditions.