儿童胎内胎的CT与MRI表现

Imaging Diagnosis of Fetus in Fetus in Children

目的 探讨儿童胎内胎的CT与MRI表现,以提高诊断水平。资料与方法 搜集4例经手术与病理证实 的儿童腹膜后胎内胎的影像与病理学资料进行回顾性分析。结果 4例瘤体均位于腹膜后。2例CT检查,瘤体 均表现为长椭圆分叶状肿块,其直径为5-11 cm不等,边缘较清楚,有明显的包膜,肿块中央包含圆形或管状骨样 结构以及脂肪组织,其周围有较大液体密度囊。增强扫描瘤实体稍强化,囊腔不强化。2例MRI检查,瘤体呈大的 混合囊性块,周围有液体信号囊包裹。囊腔在T2WI为高信号,没有明显钙化、椎骨及肢体结构显示。结论 CT 和MRI对胎内胎的诊断有重要价值,尤其是CT较MRI在显示钙化、骨结构方法更具有优越性。对于椎骨或长骨的 存在是本病诊断的关键,以此区别于畸胎瘤。

Objective To discuss the CT and MR imaging features of fetus in fetus so as to improve the accuracy of diagnosis, Materials and Methods Imagings findings and clinical data were retrospectively evaluated in 4 patients of fetus in fetus with pathologically proved in the retroperitoneum, Results Of the 4 cases, the masses were located in the retroperitoneum, and were commonly surrounded by encapsulated fluid, The diameter of the masses was 5cm to llcm, The edge of mass was clear with peripheral envelope, The CT findings were consisted of a round or tubular collection of fat surrounded a central bony structure in 2 cases, It was surrounded by fluid-density sac. On enhanced images, the masses were shown as slightly enhancement. On MRI of 2 cases, the lesions were shown as the large complex mass with surrounding fluid-signal sac. Sac was visualized as hyperintensity on T2WI. The presence of a vertebral axis , calcification and limbs were unconspicuous on MR images. Conclusion CT and MR imaging features are very useful for the diagnosis of fetus in fetus, CT is especially better than MRI for the display of calcification and ossific component. The identification of vertebrae or long bones is essential for establishing this diagnosis prospectively, which helps us to exclude the diagnosis of teratoma.