脑膜瘤MR扩散张量成像研究

Study of MR Diffusion Tensor for Meningiomas

目的 探讨平均扩散系数(ADC)和各向异性分数(FA)在脑膜瘤诊断中的价值。资料与方法 2 8例脑膜瘤在治疗前行常规MRI及扩散张量成像(DTI)。在T1WI增强、T2 WI及FA图上确定肿瘤、水肿、肿瘤邻近及对侧正常白质区。测量、分析这些区域的FA值和ADC值。结果 脑膜瘤Ⅰ级:水肿区ADC值高于肿瘤实体区、肿瘤邻近正常白质区及肿瘤对侧正常白质区(P <0 .0 5 )。肿瘤邻近及对侧白质区FA值高于肿瘤实体区、水肿区(P <0 .0 5 )。肿瘤实体区与水肿区FA值无显著性差异(P >0 .0 5 )。脑膜瘤Ⅱ+Ⅲ级:水肿区ADC值高于肿瘤实体区、肿瘤邻近及对侧白质区(P <0 .0 5 ) ,实体区和肿瘤邻近及对侧白质区ADC值亦有显著性差异(P <0 .0 5 )。肿瘤邻近白质区FA值高于实体区和水肿区(P <0 .0 5 )。脑膜瘤Ⅰ级肿瘤实体区、水肿区、邻近白质区ADC值与脑膜瘤Ⅱ、Ⅲ间具有显著性差异(P <0 .0 5 ) ,肿瘤邻近白质区FA值亦有显著性差异(P <0 .0 5 )。结论 ADC图有助于区分肿瘤实体区和水肿区。FA图可清晰显示正常白质纤维和肿瘤的解剖关系,利于术前手术方案制定。结合常规MRI,DTI有助于脑膜瘤良。

Objective To evaluate the value of FA and ADC in the diagnosis of meningiomas.Materials and Methods 28 patients with meningiomas were underwent conventional MR and DTI before treatment. Tumor, edema, contralateral normal white matter and regions near the tumors were determined on T 2WI, contrast-enhanced T 1WI and FA images. Average diffusion coefficients (ADC) value, ADC maps, fractional anisotropy (FA) value and FA maps were calculated in areas which mentioned above.Results Grade Ⅰ meningiomas: ADC value in the edema was higher than that of tumor, the normal white matter around and opposite the tumors (P<0.05). FA value in the contralateral normal white matter and regions near the tumors was higher than that of tumor and edema (P<0.05), there were no significant difference in FA value between tumor and edema (P>0.05). Grade Ⅱ+Ⅲ meningiomas: ADC value in the edema was higher than that of tumor, the white matter around and opposite the tumors (P<0.05), the ADC value in tumors was also significant difference from the white matter around and opposite the tumors (P<0.05). FA value in the white matter around the tumors was higher than that of tumor and edema (P<0.05). The significant difference in ADC value were found in tumors,edema, and the white matter around tumors between gradeⅠand Grade Ⅱ+Ⅲ meningiomas (P<0.05). FA in the white matter around tumors was also found significant difference between gradeⅠand Grade Ⅱ+Ⅲ meningiomas.Conclusion ADC map can be used to differentiate between tumors and edema, FA map can display the detailed relationship between tumors and nearby white matter tract, and it is useful to determine the plan before surgery. Combined with conventional MRI, DTI may be helpful in grading for meningiomas.