Endoscopic retrograde pancreatography: analysis of the normal pancreatogram, and changes which are associated with chronic pancreatitis and pancreatic cancer.

The dimensions of the normal pancreatogram were determined by studies in 30 adults without demonstrable pancreatic disease. The main pancreatic duct had a mean maximum diameter of 3.1 mm, 2.4 mm and 1.4 mm in the head, body and tail of the pancreas respectively; diameters at the upper limit of normal were 4 mm, 3 mm, and 2 mm in these three regions; Changes in the main pancreatic duct were categorized, and the relative frequency of these changes was determined in 45 patients with chronic pancreatitis and 14 patients with pancreatic cancer; Obstruction of the main duct was usually associated with cancer, whereas dilatation throughout the duct was only observed in chronic pancreatitis, Segmental stricture was common in both diseases, but analysis of the corresponding cholangiogram permitted differentiation in some patients. Gross distortion of the duct system occurred only in chronic pancreatitis, and was frequently associated with calcification which was seen on plain abdominal X-ray film. The main pancreatic duct showed no abnormalities in five patients (11%) with chronic pancreatitis, and one patient (7%) with cancer. Analysis of changes in the main pancreatic duct usually permitted differentiation of chronic pancreatitis from pancreatic cancer.