Oral cholecystography is a radiological procedure used to visualize the gallbladder and biliary channels, developed in 1924 by American surgeons Evarts Ambrose Graham and Warren Henry Cole. It is usually indicated in cases of suspected gallbladder disease, and can also be used to determine or rule out the presence of intermittent obstruction of the bile ducts or recurrent biliary disease after biliary surgery.A radiopaque cholegraphic (contrast) agent, usually iopanoic acid (Telepaque) or its sodium or calcium salt, is orally administered, which is absorbed by the intestine. [Source: Wikipedia 
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