Perfusion Computed Tomography Findings of Autoimmune Pancreatitis

Objectives: The aim of this study was to clarify the pancreatic blood perfusion in patients with autoimmune pancreatitis (AIP) and the changes after steroid treatment. Methods: Perfusion computed tomography was performed in 11 patients with AIP and 12 control subjects. Pancreatic volumetric blood flow (F(V)), volume of distribution (V(D)), and blood transit time (T) were determined from a single-compartment kinetic model. Nine patients with AIP were reexamined by perfusion computed tomography after corticosteroid administration. Results: The pancreatic F(V) values of the 11 patients with AIP (82.7/min) were significantly lower than those of control subjects (163.5/min, P = 0.0006). On the other hand, the pancreatic V(D) and (T) values were not significantly different between AIP and normal. After steroid treatment, the F(V) values of 9 reexamined patients with AIP (76.2/min) were significantly elevated (109.8/min, P = 0.0391). However, the changes of the values after the treatment differed in degree among individuals. The values of 4 patients were dramatically elevated to greater than 100/min, whereas those of 4 other patients did not improve well. The value of the remaining patient whose initial FV value was normal (168.09/min) did not change after the treatment. Conclusions: Pancreatic volumetric perfusion was attenuated in AIP patients. The perfusion was improved after the steroid treatment.