Figure 8b. Coronal RARE MR images (2,800/1,100, 20-mm section thickness). (a) Image obtained before the administration of secretin shows high signal intensity within the gallbladder (GB), stomach (S), and duodenum (D). The common bile duct (short arrow) is seen, but the main pancreatic duct is seen only in the pancreatic head (long arrow) on this thick section. The accessory duct (arrowhead) is barely seen. (b) Two minutes after the intravenous injection of secretin, the pancreatic duct (short arrows) is distended and well depicted in the pancreatic body; it inserts into the major papilla (long arrow). The accessory duct is now seen in the pancreatic head (arrowhead). Note increased fluid in the jejunum (J).