胰腺实性-假乳头状瘤的CT和MRI诊断及鉴别诊断

目的：探讨CT和MRI对胰腺实性-假乳头状瘤的诊断及鉴别诊断依据。方法：回顾性分析经手术及病理证实的13例胰腺实性-假乳头状瘤的影像资料。CT扫描12例， MRI扫描4例。结果：11例位于胰腺边缘，瘤体呈类圆形或椭圆形囊实性团块影。肿块边缘清楚。CT平扫呈低密度，7例显示了瘤体钙化。MRI扫描4例，在T1WI、T2WI上呈高、低混杂信号，实性部分在T1WI呈稍低信号，T2WI呈等或稍高信号；囊性部分T1WI呈低信号，T2WI呈高信号。CT与MRI增强扫描显示实性部分均有强化，最大肿块实质-胰腺强化对比差，在动脉期，到门静脉期和平衡期与正常胰腺强化基本一致；囊性部分各期均无强化。结论：胰腺实性-假乳头状瘤CT和MRI影像具有一定特征性，结合临床特点可以做出诊断及鉴别诊断。

Diagnosis and differential diagnosis of solid-pseudopapillary tumors of the pancreas by CT and MRI

Objective: To study the CT and MRI features of solid-pseudopapillary tumors of the pancreas(SPTP). Methods: Imaging findings of 13 patients with histopathologically proven SPTP were analyzed retrospectively. CT was performed in 12 patients and MRI in 4 patients. Results: Eleven masses were located in the marginal zone of the pancreas. The SPTP were round or elliptial, while the tumors involving both cystic portions and solid portions. All tumors have clear margins. On CT scans, the tumors were low density. Seven masses showed calcification. All masses were mixed hypo- and hyperintense on T1WI and T2WI in 4 cases, and solid portions of mass showed slightly hypointense on T1WI, and iso- or slightly hyperintense on T2WI; and cystic portions of mass showed hypointense on T1WI, and hyperintense on T2WI. On enhanced CT and MRI scans, solid portions showed marked enhancement and cystic portions showed no enhancement. The most marked density contrast between lesions and normal tissue showed on arterial phase, and the contrast of the lesions were equal to the normal tissue on portal vein and balancing phase. Conclusion: There are some characteristics on CT and MRI manifestation of SPTP. The correct imging diagnosis and differential diagnosis is possible based on clinical characteristic and CT or MRI findings.