Endoscopic retrograde cholangiopancreatography (ERCP) is a technique that combines endoscopy and fluoroscopy for the diagnosis and treatment of certain disorders of the biliary tree or the pancreatic duct.

It is a specialised procedure in which the physician advances a side-viewing endoscope through the stomach and the first part of the duodenum, as far as the junction of the common bile duct and the pancreatic duct (the ampulla of Vater). Contrast medium can then be injected into the ducts of the biliary tree and the pancreas so that they become visible on X-ray images.

ERCP is used mainly for the diagnosis and treatment of conditions of the bile ducts and the main pancreatic duct, including gallstones, inflammatory strictures (scarring), leaks (from trauma and surgery) and cancer.

The procedure is usually performed after the intravenous administration of medication for sedation, with continuous monitoring of the patient’s cardiorespiratory vital parameters. This allows for a calm, essentially painless and thorough examination. The side-viewing endoscope is then introduced through the mouth into the oesophagus, the stomach and, through the pylorus, into the duodenum, where the ampulla of Vater is located. The sphincter of Oddi is a muscular valve that controls the opening of the ampulla. When required, your physician may perform a small incision (sphincterotomy), which facilitates access so that stones can be removed or other treatment can be carried out with ease.

In selected cases the gastroenterologist can advance a miniature endoscope through the working channel of the standard endoscope into the biliary tree and obtain direct visualisation of its lumen. This technique is called cholangioscopy and it serves to fragment large stones by lithotripsy or to take targeted biopsies from specific points of the biliary tree and the pancreatic duct for the diagnosis of malignancy.

Complications of ERCP are not common, although it remains a specialised and invasive procedure. Irritation of the pancreas occurs in 5% of cases, while others such as bleeding or infection occur in about 1% of patients.

Note: This article does not replace the detailed explanation of the ERCP and cholangioscopy procedure given by your gastroenterologist.

Key figures

  • MRCP is diagnostic, ERCP is primarily therapeutic
  • Cholangioscopy allows targeted biopsy from the stricture itself
  • Post-ERCP pancreatitis is the most important complication
  • ERCP is not used as a diagnostic test when imaging suffices

The conditions most often treated this way are gallstones of the bile duct and strictures, including those caused by cholangiocarcinoma, where cholangioscopy allows targeted biopsy from the stricture itself.

Frequently asked questions

MRCP is a purely diagnostic magnetic resonance study that maps the ducts without any instrument entering the body. ERCP is an endoscopic procedure that is primarily therapeutic: it removes stones, dilates strictures and places stents. Diagnostic questions are answered first by MRCP or endoscopic ultrasound, and ERCP is reserved for treatment.

It allows direct visual inspection inside the bile duct and targeted biopsies from the stricture itself, which imaging cannot provide. This matters because distinguishing a malignant stricture from a benign one is not always possible on imaging alone, and the distinction changes management entirely.

The most important is post-ERCP pancreatitis. Risk is reduced by careful patient selection, technique, and preventive measures where indicated. This is why ERCP is not used as a diagnostic test: when the aim is only to look, MRCP or endoscopic ultrasound carry no such risk.

Sources

Content last updated: September 2026 (22/09/2026).