What is magnetic resonance cholangiopancreatography (MRCP), and how does it compare with endoscopic retrograde cholangiopancreatography (ERCP)?
MRCP is a noninvasive MR imaging technique that is performed through acquisition of very heavily T2-weighted images such that only fluid-filled structures, in particular the pancreaticobiliary tree, have very high signal intensity, whereas other background tissues and organs have very low signal intensity. It is typically performed as part of a complete abdominal MRI examination, so that information about the surrounding soft tissues is also provided.
ERCP is an invasive technique that is performed by gastroenterologists during patient sedation by passage of an endoscope into the stomach and duodenum. It allows for direct visualization of the mucosa of the stomach and duodenum, direct visualization of the ampulla, and biopsy of lesions encountered. Contrast material is injected into the common bile duct and pancreatic duct, and then x-ray fluoroscopic images are acquired to create images of these ductal systems. Since the advent of MRCP, ERCP is performed less often for diagnostic purposes unless a therapeutic procedure is also planned such as removal of calculi, dilation of a sphincter, dilation of a stricture, or stent placement.