中文摘要：

目的：总结自身免疫性胰腺炎（AIP）的CT及MRI影像学特征，探讨其诊断与鉴别诊断要点。 方法：采用回顾性描述性研究方法。收集2012年2月至2015年2月内蒙古医科大学附属医院收治的21例AIP患者的临床资料。患者行CT平扫及增强扫描、MRI平扫及增强扫描、MRCP检查，完善检查后行激素治疗。选取同一时期行MRI检查并确诊的胰腺癌及正常胰腺受试者各11例，分别测量其表观弥散系数（ADC）值进行比较。观察指标：（1）影像学检查情况：①胰腺表现：胰腺密度和信号，胰腺萎缩和钙化，胰腺增大，胰管改变。②胰腺外表现：胆道系统及肾脏改变。③弥散加权成像（DWI）及ADC值：比较AIP、胰腺癌和正常胰腺ADC值。（2）诊断情况。（3）治疗及随访情况。采用门诊及电话随访，随访内容为患者的临床症状及体征，随访时间截至2016年2月。正态分布的计量资料以±s表示，多组间比较采用单因素方差分析。两两比较采用Dunnett′ T3法检验。 结果：（1）影像学检查情况：21例患者中，17例行CT检查，11例行MRI检查（其中7例联合行CT检查）。①胰腺表现：胰腺密度和信号MRI检查示胰腺弥漫性增大14例，边缘饱满，呈“腊肠样”改变。CT平扫呈均匀等密度影，增强扫描动脉期强化程度减低，门静脉期及延迟期逐渐均匀强化，边缘未见强化。MRI平扫病灶T1加权成像呈稍低信号，T2加权成像呈稍高信号，DWI呈高信号，增强扫描呈延迟强化；病灶边缘T1、T2加权成像均呈稍低信号，增强未见强化。胰腺萎缩和钙化：3例胰腺实质萎缩，内见散在钙化。胰腺增大：4例胰腺局限性增大呈“假肿瘤样”改变，其中胰头部局限性增大2例。胰管改变：MRCP检查示4例表现为胰管弥漫性狭窄，3例表现为局限性狭窄，1例局限性扩张。②胰腺外表现：MRCP检查示11例患者表现为胆道?

英文摘要：

Objective：To summarize the features of computed tomography （CT） and magnetic resonance imaging （MRI） of autoimmune pancreatitis （AIP） and investigate the key points of diagnosis and identification. Methods：The retrospective and descriptive study was conducted. The clinical data of 21 patients with AIP who were admitted to the Affiliated Hospital of Inner Mongolia Medical University between February 2012 and February 2015 were collected. All the patients underwent plain and enhanced scans of CT and MRI, and magnetic resonanced cholangiopancreatography （MRCP）, and then received hormone therapy. Eleven patients with pancreatic cancer and 11 normal subjects who were diagnosed by MRI in the same period were selected, and apparent diffusion coefficient （ADC） was calculated and compared. Observation indicators： （1） situation of imaging examination： ① pancreatic manifestations： density, signal, atrophy, calcification and enlargement of pancreas, change of pancreatic duct, ② manifestations out of pancreas： changes of biliary tract system and kidney, ③ diffusion weighted imaging （DWI） and ADC： comparisons of ADC among AIP, pancreatic cancer and normal pancreas; （2） diagnosis; （3） treatment and followup. The followup using outpatient examination and telephone interview was performed to detect the clinical symptoms and signs up to February 2016. Measurement data with normal distribution were represented as ±s. Comparisons among groups were done using oneway ANOVA. Pairwise comparison was analyzed by Dunnett′ T3 test. Results：（1） Situation of imaging examination： Of 21 patients, 17 received scan of CT and 11 received scan of MRI （7 combined with scan of CT）. ① Pancreatic manifestations： 14 patients had diffuse enlargement of pancreas, with full edge and ＂sausagelike＂ change. Plain scan of CT showed uniform isodense shadow, and enhanced scan showed that reduced enhancement in arterial phase and gradually homogenous enhancement in portal vein pha