Oral cholecystography is a procedure used to visualize the gallbladder by administering, by mouth, a radiopaque contrast agent that is excreted by the liver. This excreted material will collect in the gallbladder, where reabsorption of water concentrates the excreted contrast. Since only 10% of gallstones are radiopaque, the remaining 90% will appear as translucent on an opaque background in an abdominal X-ray. Current medical practice prefers ultrasound and CT over oral cholecystography. If needed, IV cholecystography and cholangiography may be done.
The oral cholegraphic (contrast) medium used is iopanoic acid (Telepaque) or its sodium/calcium salt.