Figure 4a.  Vertically oriented pancreatic duct detected incidentally in a 72-year-old man with abdominal pain. (a) MR cholangiopancreatogram reveals a vertically oriented pancreatic duct (arrows) mimicking the distal bile duct. The gallbladder (arrowheads) is seen adjacent to the pancreatic duct. (b) MR cholangiopancreatogram obtained 10 mm posterior to a depicts the course of the extrahepatic bile duct (arrows), which parallels that of the vertically oriented pancreatic duct (cf a). The gallbladder (arrowheads) and duodenal bulb (*) are also seen. (c) MR cholangiopancreatogram obtained 5 mm posterior to a shows the distal bile duct (arrow) lateral to the vertically oriented pancreatic duct (arrowheads). A fluid-filled periampullary diverticulum (*) is demonstrated incidentally.