Cholecystography
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.