Autoimmune pancreatitis: study of CT manifestation
NI Rui-jun1, WANG Bo-yin1, XU Shun-liang2, RUAN Ling-xiang2
1. Department of Radiology, Shaoxing City People’s Hospital, Shaoxing Zhejiang 312000, China; 2. The First Hospital of Zhejiang University, Hangzhou 310003, China
Abstract：Objective: To investigate the CT imaging findings of autoimmune pancreatitis(AIP). Methods: The CT data of 11 patients with AIP were reviewed retrospectively. Plain CT scanning and dynamic contrast-enhanced scanning were performed in 11 patients. The location, shape of abnormal pancreas and the shape of boundary between normal and abnormal pancreas in segmental AIP were analyzed(in this text, the boundary is called “front-end” of abnormal pancreas, and the abnormal pancreas between the boundary and the most bulky abnormal pancreas is called “forepart”). The CT attenuation value of the pancreatic parenchyma of AIP and normal pancreas in plain scanning, the arterial phase, portal vein phase and delayed phase were calculated. The mean CT attenuation value of the pancreatic parenchyma in patients with AIP was compared with that in patients with a normal pancreas(n=25). Results: Four patients showed diffuse swelling of the pancreas and 7 patients showed segmental enlargement of pancreas. The tiny front-end and cone-shaped forepart was seen in 2 patients with segmental AIP, and the flat front-end and trapezoid forepart in 1 patient with segmental AIP, and the arcuate front-end and mimic bullet-point forepart in 3 patients with segmental AIP; the mimic bullet-point forepart at one side and the cone-shaped forepart at another side of abnormal pancreas in 1 patient with segmental AIP. Fusiform body of abnormal pancreas was seen in 3 patients of segmental AIP, irregular columnar body of abnormal pancreas with coarse edge in 3 patients with segmental AIP, and sausage body of abnormal pancreas in 5 patients. Abnormal pancreas showed homogeneous density, and the mean CT attenuation value of the abnormal pancreatic parenchyma was slightly lower than that of control group on plain scanning, significantly lower than that of control group in the arterial phase, slightly higher than that of control group in the portal vein phase. Conclusion: Abnormal pancreas of AIP may represent various shape, whereas there is some distinctive CT imaging manifestations. CT dynamic contrast-enhanced scanning play an important role in differentialing AIP and other massive lesions. AIP can be diagnosed correctly through CT examination.
2011, Vol. 22 
