What is a hepatobiliary scan?

A hepatobiliary scan uses Tc-99m IDA to detect biliary tract pathology. Tc-99m IDA has uptake, transport, and excretion path-ways that are identical to those of bilirubin: it is cleared from the bloodstream by the liver, excreted into the biliary ducts, and excreted into the bowel. It also fills the gallbladder under the same physiologic conditions that cause bilirubin to fill the gallbladder (e.g., no recent meals).