1. An examination of the biliary tract system or the organs, ducts, and other structures that participate in secretion (the liver), storage (the gallbladder), and delivery (hepatic and bile ducts) of bile into the duodenum (the first section of small intestine beyond the stomach).
2. The visual examination of bile ducts utilizing a fiberoptic endoscope (an optical system in which the image is conveyed by a compact bundle of small diameter, flexible, glass or plastic fibers).