颅内毛细胞星形细胞瘤的MRI诊断

MRI Diagnosis of Pilocyticastrocytoma in Intracalvarium

目的探讨毛细胞星形细胞瘤的MRI特点。资料与方法回顾性分析经手术、病理证实的13例毛细胞星形细胞瘤的MRI表现,探讨肿瘤的部位、形态、信号等特点,并与病理诊断结果做对比。结果 13例毛细胞星形细胞瘤中,儿童及青少年8例;小脑蚓部5例,其他部位8例。MRI扫描:肿瘤完全囊变者1例,囊实性者9例,实性者3例,伴附壁结节者1例。T1WI上囊性部分呈低信号,实性部分呈等低信号,T2WI上囊性部分呈高信号,实性部分呈等高信号。增强扫描囊性部分不强化,实性部分及附壁结节呈明显强化。肿瘤DWI低信号11例,等低混杂样信号2例,SWI可见低信号2例。伴有轻度瘤周水肿及梗阻性脑积水各3例。结论毛细胞星形细胞瘤好发于儿童及青少年,小脑蚓部多见,多为囊实性,占位效应较轻,MRI表现有一定的特征性。

Purpose To evaluate the MRI features of pilocytic astrocytoma.Materials and Methods Thirteen patients＇ MRI manifestations with pilocytic astrocytoma were retrospectively reviewed.Imaging features were analyzed including the position,appearance,signal of the pilocytic astrocytoma,and compared with pathology.Results Of all the 13,eight cases were pediatric.Five cases were in nodulus cerebella while eight cases were in other location.One case showed mural nodule.MRI manifestations included cystic degeneration in one tumor,nine cysticsolid,three solid.On T1-weighted images,the cystic portion was hypointensity and solid portion was isointensity or hypointesity;on T2-weighted images,the cystic portion was hyperintensity and solid portion was isointensity or hyperintensity.The solid portion and mural nodule showed marked enhancement,and the cystic degeneration showed no enhancement.DWI of 11 tumors were hypointensity.The other two were isointensity or hypointesity.SWI was isointensity or hypointesity in 2 tumors.Six tumors had peritumoral edema and obstructive hydrocephalus.Conclusion The pilocytic astrocytoma is usually seen in children and teenagers.Most of the tumors are cystic-solid.MRI of pilocytic astrocytoma has characteristic imaging findings.