幕上脑实质室管膜瘤CT和MR诊断

CT and MR diagnosis of supratentorial intraparenchymal ependymoma

目的：分析幕上脑实质室管膜瘤ＣＴ和ＭＲ影像学特点。材料与方法：２４例经手术病理证实的幕上脑实质室管膜瘤，行ＣＴ和（或）ＭＲ检查；男１６例，女８例；１０岁以下９例，１１～２０岁６例，２０岁以上９例。结果：部分囊性型２１例，好发于顶叶，肿瘤部分为囊性，实质较少，囊液在ＣＴ平扫时稍高于脑脊液密度，ＭＲＴ１加权像信号稍高于脑脊液，Ｔ２加权像似脑脊液高信号。肿瘤实质在ＣＴ平扫时呈稍高密度或等密度，ＭＲＴ１加权像信号稍低于脑实质，ＭＲＴ２加权像似灰质信号或稍高于灰质信号。实质内常有条状或点状钙化。瘤周一般无水肿或仅有轻度水肿，增强扫描肿瘤实质及囊壁轻到中度强化。完全实质型多见于年长的成人，肿瘤好发于额叶，且常累及双侧，ＣＴ平扫时肿瘤多呈稍高密度，出血和钙化多见，瘤周水肿明显，多呈显著不均质强化。结论：幕上脑实质室管膜瘤可分为部分囊性型和完全实质型，部分囊性型ＣＴ和ＭＲ表现很有特点，常能提供准确诊断，完全实质型与胶质瘤鉴别困难。

Purpose: To analyse the CT and MRI features of supratentorial intraparenchymal ependymoma. Materials and methods: Twenty four cases of supratentorial intraparenchymal ependymoma proved by surgery and pathology had CT and MRI scanning. There were 16 males and 8 females. Nine cases were below 10 years old, 6 11～20 years old, and 9 over 20 years. Results: Twenty one cases of supratentorial intraparenchymal ependymoma were partial cystic. The consistency of the tumors was mostly cystic. The cyst fluid was low density on CT scan, slightly greater than intensity of CSF on MR T 1 weighted, CSF like high intensity on T 2 weighted. The solid of the tumor was iso or slightly hyper dense, slightly hypo intense on T 1 weighted imaging and slightly hyperintense on T 2 weighted imaging. The calcification was common in the solid of tumor. The peritumoral edema was absent or minimal. The solid of tumor and wall of cystic part were mild to moderate enhancement after contrast administration. Solid was common in elder adults, frequently involving the bifrontal. On CT scan, the tumor was slightly hyperdense with marked inhomogeneous enhancement after contrast injection. The intratumoral calcification and hemorrhage were common. The peritumoral edema was marked. Conclusion: Supratentorial intraparenchymal ependymoma might be divided into partial cystic and solid. The CT and MR findings of partial cystic are characteristic, and offer accurate diagnosis. The differentiation of solid and glioma is difficult.