非小脑蚓部髓母细胞瘤的CT和MRI表现

CT and MR imaging characteristics of non-cerebellar-vermis medulloblastoma

目的:探讨非小脑蚓部髓母细胞瘤的CT和MRI征象,提高对髓母细胞瘤的诊断水平。方法:回顾性分析57例经手术病理证实的非小脑蚓部髓母细胞瘤术前CT及MRI资料。结果:57例髓母细胞瘤中,8例病灶位于桥小脑角区,病灶位于左、右、双侧小脑半球分别为23例、19例、7例。CT平扫肿瘤呈等密度或稍高密度,MRI上肿瘤呈稍长T1稍长T2信号。肿瘤内部囊变坏死者46例,且囊变内壁多较光滑;病灶圆形或椭圆形45例;边界不清、较清、清晰各18例、12例、27例;肿瘤周围有不同程度水肿,发生梗阻性脑积水32例。33例有增强图像,其中9例呈轻度片状强化,18例中度块状、片状强化,6例块状不均匀明显强化。结论:MRI对非小脑蚓部髓母细胞瘤的显像较CT更有优势,其诊断价值较大。

Objective：To investigate CT and MRI imaging characteristics of non-cerebellar-vermis medulloblastoma（NCVM）,in order to optimize diagnostic accuracy of medulloblastoma.Methods： Retrospective analysis of CT and MRI images were performed in 57 patients with pathologically proven NCVM.Results：In the 57 cases,NCVMs were located in the cerebellopontine angle region（n=8）,the left（n=23）,right（n=19） and bilateral cerebellar hemisphere（n=7）,respectively.On CT examination,NCVMs showed iso-or slight hyper-density.On MRI images,NCVMs appeared as slight hypointensity on T1WI and slight hyperintensity relative to the gray matter on T2WI.Of the 57 cases with NCVMs,46（80.7%） had cystic or necrotic components with smooth inner wall,45（78.9%） had round or oval shape.Unclear（n=18）,relatively clear（n=12） and clear（n=27） tumor boundaries were presented.Varying degrees of peritumoral edema were found and obstructive hydrocephalus were presented in 32 cases.NCVMs exhibited mild enhancement（n=9）,moderate enhancement（n=18） and intense enhancement（n=6） in the 33 cases with contrast administration.Conclusion：NCVM has some specific imaging features.MRI is superior to CT in the detection of NCVM.