肿块型慢性胰腺炎包括以纤维化的肉芽组织增生为特征的普通型肿块型慢性胰腺炎和以致密的淋巴浆细胞浸润伴丰富纤维化增生为特征的肿块型自身免疫性胰腺炎两种病理类型，在临床上有时均很难与胰腺癌鉴别。准确的术前诊断与鉴别对于其治疗及预后有着极为重要的意义。肿块型慢性胰腺炎与胰腺癌在CT和MRI上分别具有一定特征性的影像学表现，特别是磁共振动态增强后信号强度-时间（signal intensity-time，SI-T）曲线及弥散加权成像（DWI）更有助于两者的鉴别，肿块型慢性胰腺炎呈慢升慢降型曲线，而胰腺癌呈渐进性升高曲线；肿块型慢性胰腺炎的表现弥漫系数（ADC）值低于胰腺癌的ADC值等。

Imaging features of mass-forming pancreatitis        ZENG Meng-su， YAO Xiu-zhong. Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032, China
Corresponding author: ZENG Meng-su，E-mail:zeng.mengsu@zs-hospital.sh.cn
Abstract    Chronic mass-forming pancreatitis usually included two pathological types: Ordinary chronic mass-forming pancreatitis, characterized by granulation tissue with fibrosis and mass-forming autoimmune pancreatitis, characterized by a dense lymphoplasmacytic infiltration with extensive fibrosis and proliferation. Sometimes it was very difficult to identify pancreatic cancer from chronic mass-forming pancreatitis in the clinical practice. Accurate preoperative diagnosis and differentiation were extremely important for their treatment and prognosis. Chronic mass-forming pancreatitis and pancreatic cancer had their own characteristic imaging findings in CT and MRI respectively, especially in the dynamic contrast-enhanced MRI and DWI. A signal intensity-time (SI-T) curve with a slow rise followed by a slow decline usually indicated chronic mass-forming pancreatitis, while a SI-T curve with a gradual rise indicated pancreatic cancer. ADC values in chronic mass-forming pancreatitis usually was lower than that in pancreatic cancer.