ERCP is a procedure used to visualise the bile duct and pancreas by producing detailed x-ray images. It uses a very long and flexible tube called an endoscope.
The endoscope is inserted through the mouth and carefully pushed down into the stomach and round into the first part of the small intestine (the duodenum). The endoscope is then used to find the opening of the bile duct that empties into the duodenum. This opening is called a papilla. A small plastic tube is then passed down the endoscope through the papilla to reach the bile duct and the pancreatic duct. A small amount of dye is then injected into the ducts to allow x-ray images to be captured.