CT demonstration of the splenic vein-pancreatic relationship: the pseudodilated pancreatic duct.

Cross-sectional anatomy of the splenic vein-pancreatic relationship is reviewed and correlated with findings on computed tomography. A layer of fat which is normally present between the splenic vein and the pancreas may simulate a dilated pancreatic duct. Distinct demonstration of the splenic vein as a structure separate from the pancreas was possible in 43 of 86 patients studied. An additional 25% of the patients had partial or indistinct demonstration of the splenic vein. Appreciation of this normal relationship on CT is imperative to avoid misinterpretation of the fat layer as a dilated pancreatic duct. In addition, the measured size of the pancreas may be falsely overestimated by addition of the splenic vein width if the intervening fat is not identified.