自身免疫性胰腺炎MRI表现及随访分析

MRI features and follow-up analysis of autoimmune pancreatitis

目的探讨自身免疫性胰腺炎(AIP)的MRI表现以及随访过程中影像动态变化。方法分析11例AIP病人的临床及MRI资料,观察AIP在类固醇治疗前、后不同时期的MRI表现。采用配对样本t检验,分别对初诊与自然病程下及初诊与类固醇治疗后的胰腺大小测量值进行比较。结果初诊时9例胰腺弥漫性肿大,1例胰头局限性肿大,1例胰体见局限性肿块;受累胰腺在T1WI低信号11例,T2WI高信号10例、等信号1例;4例显示胰周低信号带;胰腺病变区7例胰管不可见,2例间断显示,1例呈串珠状改变,1例胰体部胰管受压、移位;9例胰腺段胆管壁增厚。自然病程下随访,5例胰腺肿大程度及MRI信号异常与初诊病变相似,4例胆管壁病变范围较初诊病变加重。类固醇治疗后,6例胰腺肿大、MRI信号异常以及胆管壁增厚趋于正常,胰周低信号带消失。有效治疗后3例胰腺病变复发,复发性AIP的MRI表现与初诊病变相似,其中1例胰体尾前方出现假性囊肿。初诊与自然病程下胰腺大小差异无统计学意义(P>0.05),初诊与类固醇治疗后胰腺大小差异有统计学意义(P<0.05)。结论 AIP的MRI表现有一定特征,MRI可用于诊断AIP,评估类固醇疗效,长期随访以及了解有无病变复发。

Objebtive To explore MRI features of autoimmune pancreatitis（AIP） at initial diagnosis and follow-up periods. Methods Clinical and MRI appearances in 11 patients with AIP were observed, and MRI features before and after steroid treatment in different periods were retrospectively analyzed. The difference in pancreatic size between initial and follow-up exam was tested with paired samples t test, comparison was done also for measures at initial and after steroid treatment. Results On initial MRI, pancreatic parenchyma showed diffuse enlargement in 9 patients, focal enlargement at the pancreatic head in 1, and focal mass at the body in 1. The involved pancreas appeared as hypo-intense on T1-weighted images in all patients, hyper-intense on T2-weighted images in 10, and iso-intense in 1. Hypo-intense rim around the pancreas was seen in 4 patients. Pancreatic duct was not visible in 7 patients, intermittent display in 2, beading change in 1,and displacement at the body in 1. Thickening of intra-pancreatic bile duct wall was seen in 9 patients. Follow-up in natural process, pancreatic enlargement and MRI signal change were similar to the initial lesions in 5 patients, progression of bile duct involvement was noted in 4. Following steroid treatment, the pancreas swelling, signal abnormalities, thickening of bile duct wall became normal in 6 patients, hypo-intense rim around the pancreas disappeared in 4 patients. Pancreatic lesions recurred in 3 patients. The lesion features in recurrence were similar to those in the original. In addition, a pseudocyst occurring in front of pancreatic body and tail was found in 1 patient. There was no significant difference in pancreatic size between initial and followup exams in the patients with natural process, and there was statistical significance before and after steroid treatment. Conclusion MRI features of AIP were characteristic, and MRI can be used in diagnosis, evaluation of steroid effect, long-term follow-up and identifying recurrence.