颅内少突-星形细胞瘤的MRI影像学评价

Evaluation of MRI Image of Intracranial Oligoastrocytomas

目的:探讨颅内少突-星形细胞瘤的MRI特征和诊断价值。方法:对18例经手术病理证实的颅内少突-星形细胞瘤患者进行MRI影像回顾性分析。结果:(1)18例患者均行MRI平扫及增强检查,病灶多位于大脑半球且同时累及灰白质(86.95%),额叶8例,颞顶叶1例,顶枕叶2例,颞枕叶2例,岛叶2例,小脑1例,胼胝体及左侧侧脑室1例,第三脑室1例;多发病灶4例,单发病灶14例;WHO-2级10例,WHO-3级8例(间变性)。(2)MRI表现:肿瘤内部多见大小不等坏死灶或囊变区(86.95%),T1WI及T2WI信号不均匀,增强扫描病灶呈明显不均匀强化,实性部分轻至中度强化,囊变区无强化。结论:颅内少突-星形细胞瘤MRI影像学表现有一定特征性,但与少突胶质瘤鉴别比较困难,而囊变或坏死的发现有可能成为鉴别诊断的关键。MRI检查可明确病灶部位及范围,结合临床可以倾向性诊断。

To investigate MRI features and diagnostic value of oligoastrocytomas.Method：MRI findings pathologically proved oligoastrocytomas of 18 patients were retrospectively analyzed.Result：（1）18 patients underwent plain and enhanced MRI examination,lesions located in the cerebral hemisphere and at the same time more involvement of gray matter（86.95%）,frontal lobe in 8 cases,1 case of temporal lobe,occipital lobe in 2 cases, temporal and occipital lobe in 2 cases,2 cases of insular lobe,1 case of cerebellum,1 case of corpus callosum and the left lateral ventricle,1 case of the third ventricle.4 cases with multiple lesions,14 cases with single lesion.In 18 cases, 10 of oligoastrocytomas were proved to be WHO gradeⅡ,8 of oligoastrocytomas were proved to be WHO gradeⅢ.（2） MRI manifestation：Ranging from the size of the focal necrosis or cystic area were often seen in tumors（86.95%）,T1WI and T2WI signal were not uniform,enhanced scan showed obvious heterogeneous enhancement,the solid part of light to moderate enhancement,cystic areas without enhancement.Conclusion：It is difficult to differentiate oligo-astrocyte mixed gliomas with pure oligodendrogliomas,because both of them have similar imaging manifestations.However,a suggestive diagnosis can be made when both clinical data and imaging features are taken into account,especially when cystic degeneration or necrosis has been found.