颞叶星形细胞瘤的MRI诊断

目的探讨MRI对颞叶星形细胞瘤的诊断和鉴别诊断要点。方法回顾性分析经手术病理证实的20例颞叶星形细胞瘤及经手术病理或治疗观察证实的9例颞叶局灶性脑炎。所有病例均行MRI常规扫描及增强扫描。观察其MRI特征及对两组病例进行对比分析。结果星形细胞瘤呈长T1、长T2异常信号。肿瘤的坏死、囊变区T2WI信号更高、T1WI信号更低。肿瘤实质无对比增强7例,轻度强化4例,明显强化9例。大脑中动脉包埋5例。瘤周水肿多较轻。18例有占位效应。局灶性脑炎亦呈长T1、长T2异常信号,但其病灶信号强弱不完全一致、病变境界不清且占位效应轻,增强扫描可见脑膜呈线状强化或脑回样强化。结论颞叶星形细胞瘤的MRI表现颇具特征性,诊断与鉴别诊断大多不难。

MRI Diagnosis of Temporal Lobe Astrocytoma

Objective To explore MRI features and diagnosis of temporal lobe astrocytoma. Methods 20 patients with cerebral astrocytoma were verified histologically,and 9 patients with focal encephalitis were verified by histology or therapy.The routine MR imaging and contrastenhancement was carried out in all cases,and study MRI characteristic of two groups. Results Astrocytoma presented as long T_1 and long T_2 signal intensity.The cystic and necrotic region of tumors demonstrated higher signal intensity on T_2 weighted imaging and lower signal intensity on T_1 weighted imaging.Tumoral core showed no enhancement in 7 cases,slightly enhancement in 4 cases and remarkable enhancement in 9 cases.Middle cerebral artery embeded in 5 cases.No evident peritumoral edema in all cases.Focal encephalitis presented as long T_1 and long T_2,but signal inhomogeneous,margins unclear,mass effect inapparent.Enhanced MRI showed linear enhanoemert of meninges or gyrus-shaped enhancement in all of focal encephalitis. Conclusion Temporal lobe astrocytoma has some specific features on MRI,it is not difficult to make a diagnosis.