Figure 13.  Periampullary diverticulum resulting in failed ERCP in a 92-year-old woman with suspected common bile duct stones. MR cholangiopancreatogram reveals a periampullary diverticulum (arrowhead) and a slightly dilated extrahepatic bile duct (straight arrow) but no common bile duct stones. Minute gallbladder calculi are also seen (curved arrow).