脑室内星形细胞瘤的MRI诊断及鉴别诊断

MRI Diagnosis and Differential Diagnosis of Intraventricular Astrocytoma of the Brain

目的探讨脑室内星形细胞瘤的MRI表现、特点及其与脑室内其他肿瘤的鉴别诊断。资料与方法回顾性分析经手术病理证实的12例脑室内星形细胞瘤的MRI资料。扫描序列包括:SE轴位T1WI、矢状位T1WI;FSE轴位T2WI。所有病例均行增强扫描。3例行磁共振波谱(MRS)研究,二维单体素,点分辨法(PRESS),TE144ms。结果脑室内星形细胞瘤的MRI表现:T1WI、T2WI多表现为不均匀信号(10/12),囊变坏死常见(9/12),病灶呈菜花状或乳头状(8/12);增强后多明显强化(9/12)且不均匀(8/12),肿瘤血管流空信号(5/12)及出血(3/12),发生率均较发生于脑实质内的相同级别的星形细胞瘤高。所有病例均未见灶周水肿,但均可见病灶以上水平脑室积水。MRS3例均有不同程度N-乙酰天门冬氨酸(NAA)降低,胆碱(Cho)上升,Cho/肌酸(Cr)和Cho/NAA的比值上升,高于正常脑组织。结论脑室内星形细胞瘤较少见,临床上常因认识不足而误诊。其MRI表现较脑实质内星形细胞瘤有所差异,需与脑室内的其他肿瘤相鉴别。MRS具有一定的鉴别诊断价值。

Objective To evaluate the MRI features of intraventricular astrocytoma of the brain and differential diagnosis of other tumors in the ventricle. Materials and Methods MR data of 12 patients with intraventricular astrocytoma proved histopathologically were analyzed retrospectively, MR sequence included SE axial T1WI, sagittal T1WI and FSE axial T2WI. All patients were performed contrast MRI and 3 of them were carried MRS with PRESS. Results MRI findings were as followings： Intraventricular astrocytomas were poorly defined with little mass effect and no edema; the signal intensity was mostly heterogeneous （10/12） on T1WI, T2WI, cystic degeneration of necrosis, cauliflower or papillary like, flow void, heterogeneity of enhancement and hemorrhage were 9/12, 8/12, 5/12, 8/12, 3/12, respectively. Elevated Cho, Cho/Cr and Cho/NAA levels as well as varying degrees of decreased NAA were depicted in all patients with MRS. Conclusion Intraventriculawr astrocytoma of the brain is less common, its MR findings are different form that of astrocytoma in the brain parenchyma, MR spectroscopy can he helpful in differentiate diagnosis.