毛细胞星形细胞瘤的MRI表现

目的：分析毛细胞星形细胞瘤的MRI特点及其病理基础，以提高对此瘤的认识。方法：经手术病理证实的毛细胞星形细胞瘤20例，回顾性分析其MRI表现。结果：毛细胞星形细胞瘤的MRI表现有如下特点：①肿瘤在T1WI上表现为稍长T1、等T1、长T1与等T1混杂信号或是长T1与短T1混杂信号，在W2Wi上大多表现为长T2为主的混杂信号；注射对比剂后肿瘤的强化方式可以分为以下五种：非强化性的囊壁及显著强化的壁结节、强化的囊壁及显著强化的壁结节、环形强化的囊壁、实性肿瘤的均匀强化、肿瘤大部分为实性成分的不均匀强化；②肿瘤形态为：不规则分叶状，不伴出血时，瘤周水肿少见或是轻微可见；伴出血时，可见明显水肿；③肿瘤多为囊性、囊实性或是呈大囊小结节型，可伴出血。结论：毛细胞星形细胞瘤有比较典型的MR／特点，结合患者的年龄及临床发病特点，有助于其术前诊断。

MRI features of pilocytic astrocytoma

Objective： In order to improve the knowlegment of pilocytic astrocytoma, MILI findings correlated with pathologic changes of this tumor were investigated. Methods： The MRI findings of pilocyfie astrocytoma were reviewed retrospectively. All eases were proved by operation and pathology. Results：The MRI characteristics of pilocytic astrocytoma were as follows： ① The tumors appeared slight hyperintense, isointense, hypointense or mixed on T1 weighted images and hyperintense or mixed on T2 weighted images; After contrast injection, the lesions were usually enhanced as follows： cystic tumor with a nonenhancing cyst wall （only the mural nodule was enhanced） ; cystic tumor with an enhanced cyst wall （the mural nodule and the cyst wall were enhanced） ; cystic tumor with an enhanced cyst wall （only the cyst wall was enhanced） ; solid tumor（regular contrast enhancement） ; mainly solid tumor （most with irregular contrast enhancement） ;② Tumors were often mutiple mierocysts. With hemorrhage, edema was seen in tumors usually, and vice versa;③ MPd study revealed a large lesion with cystic components and solid or cystic components and associated with hemorrhage. Conclusion：The MRI appearances of the pilocytie astrocytoma are nharacteristic. It is easily differentiated from other lesions by analysis of the correlation between ages and clinical feature.