
Keywords: ERCP، cholangiopancreatography رتروگراد endoscopic; AP, annular pancreas; CT, computed tomography; ERCP, endoscopic retrograde cholangiopancreatography; MRCP, magnetic resonance cholangiopancreatography; EUS, endoscopic ultrasonographyAnnular pancreas; Duodenal obstruction; Pancreatitis; Pancreatic surgery