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.