自身免疫性胰腺炎CT及MRI表现

目的:探讨自身免疫性胰腺炎(AIP)CT及MRI表现特点,加深对此少见病的认识,提高对AIP的诊断水平。方法:回顾性分析11例经手术及临床证实为AIP的CT及MRI影像学资料,总结其影像学特征。11例全部行CT检查,其中有7例同时行MRI检查。结果:全部病例中有7例AIP表现为胰腺弥漫性肿大,4例为局限性肿大。病变胰腺CT平扫表现为等密度或稍低密度,MRI扫描在T2WI上信号轻度升高,T1WI上信号降低;增强扫描胰腺实质在动脉期强化减弱,门脉期及延迟期呈渐进性强化且强化均匀。MRI有5例显示包膜样环,CT有4例显示包膜样环,CT不能显示胰管狭窄段,MRCP有4例显示胰管狭窄段。胰腺外表现主要为:胆管壁增厚并管腔狭窄5例,脾血管包埋变细4例,肾脏受累3例,腹膜后淋巴结肿大6例,肠系膜血管周围及腹膜后纤维化各1例。经类固醇激素治疗后影像学复查显示胰腺内外病变均有不同程度好转。结论:AIP患者胰腺内、外CT及MRI表现均具有一定特征。其影像学表现结合类固醇激素治疗有效,可做出正确诊断,避免患者不必要的手术治疗。

CT and MRI Manifestations of Autoimmune Pancreatitis

Objective: To explore the CT and MRI manifestation features of Autoimmune pancreatitis(AIP), deepen the understanding to this rare disease, and improve the diagnosis level of AIP. Methods: The CT and MRI imaging data of 11 cases confirmed as AIP by operation and clinic were retrospectively analyzed, summarize the imaging features. All the 11 cases took CT examination, including 7 cases of MRI examination at the same time. Results: 7 cases of AIP were characterized by diffuse enlargement in pancreas, and the other 4 cases localized enlargement. Diseased pancreas appeared isodensity and low density on CT scanning. The signal intensity of pancreas on T1 WI was lower, and slight elevated on T2 WI. The enhancement decreased during enhanced scanning in arterial phase, and the enhancement became progressive and evenly in portal venous phase and delayed phase. Capsular ring can be seen in six cases on MRI, and 4 cases of capsular ring showed on CT, CT cannot display stenosis of the pancreatic duct. 4 cases of stenosis showed on MRCP. The manifestations of related organs and tissues outside the pancreas are mainly presented as follows: bile duct wall thickening and luminal stenosis in 5 cases, splenic vessels embedding became thinner in 4 cases, renal involvement in 3 cases, and retroperitoneal lymph node enlargement in 6 cases. The fibrosis around mesenteric blood vessels in 1 case and retroperitoneal fibrosis in 1 case after treatment with steroids, imaging review showed that internal and external pancreatic lesions both have different degree of improvement. Conclusion: The internal and external CT and MRI manifestation of AIP presents some specific characteristics. With its imaging manifestation in combination with effective steroid hormone therapy, correct diagnosis can be made, and unnecessary surgical treatment for patients can be avoided.