颅底骨源性肿瘤的MRI影像诊断

Bone Tumor of the Skull Base: MR Imaging Features

目的：分析颅底骨源性肿瘤的ＭＲＩ表现并与ＣＴ和病理对照，研究ＭＲ在诊断中的价值与限度。材料与方法：搜集了经手术病理证实的颅底骨源性肿瘤２２例（软骨肉瘤３例，软骨瘤２例，转移瘤２例，脊索瘤１０例，骨巨细胞瘤２例，恶性纤维组织瘤１例，骨化性纤维瘤２例），全部行ＭＲ检查（１１例行增强检查），８例行ＣＴ检查。结果：绝大部分肿瘤均有一清晰的边缘，Ｔ１Ｗ上呈低或等信号，Ｔ２Ｗ上呈不均匀高信号，Ｔ１Ｗ上呈低信号区域随Ｔ２Ｗ回波时间延长信号仍低提示钙化，病理基础是肿瘤内基质大量钙化及纤维软骨成分。增强后除转移瘤外均为不均匀强化，同时ＭＲ对显示斜坡、岩骨的破坏较敏感，但不如ＣＴ精确。结论：ＭＲＩ是诊断颅底骨源性肿瘤的有效方法。

Objective: To report the MRI features of the bone tumors in cranial base with comparison of CT and pathology, and evaluate the value of MR in diagnosis. Materials and Methods: 22 patients with pathologic proved included: chondrosarcoma (n=3); chondroma (n=2); chordoma (n=10); giant cell tumor (n=2); ossifying fibroma (n=2); fibrous histocytoma (n=1); metastasis (n=2). All patients were performed with MR (11 cases with post contrast MRI), 8 patients were evaluated with CT. Results: Most of the tumors were well defined, on T 1W they had low intermediate signal intensity, on T 2W they were inhomogeneous high signal intensity. The low signal intensity on T 1W were still low when echo time on T 2W were increased, it suggested calcification which was caused by matrix mineralization and fibrocartilaginous. On post contrast MR imaging, they were inhomogeneous enhanced except metastasis. MR was sensitive in demonstration the destruction of clivus and petrous bone, but CT is superior to MR in that. Conclusion: MRI is a effective methods in diagnosis, espically it can determine the localization of tumors accruately.