探讨MRI及扩散加权成像（DWI）在自身免疫性胰腺炎(AIP)诊断中的价值。

回顾性研究2013年1月至2014年6月在中山大学孙逸仙纪念医院接受诊治且经病理学检查证实的11例AIP患者临床资料。其中男7例，女4例；平均年龄（54±15）岁。所有患者均签署知情同意书，符合医学伦理学规定。采用MRI平扫、多期动态增强扫描及DWI检查测量患者胰腺病灶的扩散系数（ADC），观察AIP的MRI及DWI影像学表现特征。

AIP病灶的MRI表现为T1WI呈等或稍低信号，T2WI呈稍高信号，动态增强扫描病变持续渐进强化。DWI检查测量病灶的ADC值为（1.09±0.09）×10^-3 mm²/s,胰腺病灶呈高信号。11例患者中，7例表现为胰腺整体弥漫性肿大，形态饱满，呈"腊肠样"外观；3例表现为胰头部局限性肿块；1例表现为胰体、尾部肿块。6例MRI检查胰腺周围见包膜样环状影，T1WI呈等或略低信号，T2WI呈略低或稍高信号，动态增强扫描动脉期无强化或低强化，延迟期延时强化，强化程度略低于胰腺实质。4例胰周及腹膜后见多个淋巴结肿大。

MRI检查有助于AIP的诊断，动态增强扫描与DWI表现可作为直接征象诊断AIP，具有较高的临床参考价值。

To investigate the value of magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in the diagnosis of autoimmune pancreatitis (AIP).

Clinical data of 11 patients pathologically diagnosed with AIP in Sun Yat-sen Memorial Hospital, Sun Yat-sen University from January 2013 to June 2014 were analyzed retrospectively. There were 7 males and 4 females with a mean age of (54±15) years old. The informed consents of all patients were obtained and local ethical committee approval had been received. Apparent diffusion coefficient (ADC) of the pancreatic lesions was measured by MRI scan, multiphase dynamic enhanced scan and DWI. The imaging features of AIP by MRI and DWI were observed.

The AIP lesions displayed iso- or slightly hypo-intense signal on T1WI and slightly hyper-intense signal on T2WI by MRI and continuous gradual enhancement by multiphase dynamic enhanced scan. The average ADC of the lesions by DWI was (1.09±0.09)×10^-3 mm²/s and the pancreatic lesions displayed high signal. Diffusely swelling pancreas with plump shape, sausage-like appearance was observed in 7 cases. Local mass were observed at the pancreatic head in 3 cases. Mass in the pancreatic body and tail was observed in 1 case. Capsule-like ring-like shadow was observed around the pancreas in 6 cases by MRI and iso- or slightly hypo-intense signal on T1WI and slightly lower- or hyper-intense signal on T2WI were observed. No enhancement or hypo-enhancement was observed in arterial phase by multiphase dynamic enhanced scan. Delayed enhancement was observed in delayed phase. The enhancement degree was mildly lower than that of pancreatic parenchyma. Multiple enlarged lymph nodes were observed around the pancreas and at the retroperitoneum in 4 cases.

MRI is useful for the diagnosis of AIP. The dynamic enhanced scan and DWI findings can be used as the direct images for diagnosing AIP and have a high clinical reference value.