核磁共振弥散张量成像在脑胶质瘤诊断中的应用研究

目的 探讨MRI弥散张量成像（DTI）技术显示胶质瘤与相邻脑白质纤维束解剖关系在脑胶质瘤诊断中的意义.方法 23例脑胶质瘤患者接受术前常规头颅MRI序列检查的同时进行DTI序列扫描,应用Functool软件进行图像分析处理,分别获得各自的部分各向异性图（FA图）、彩色编码张量图及脑白质纤维束图;并测定胶质瘤肿瘤病灶区、灶周水肿区及正常白质区的平均弥散系数（MD值）、各向异性图;进行FA图像信号强度及对比度的分析研究,分析脑胶质瘤与相邻脑白质纤维束的解剖关系.结果 所有病例均成功实现包括DTI序列扫描以及FA图像生成.脑白质纤维束显示为显著的高信号结构,灰质显示为等信号,脑脊液显示为低信号,脑内肿瘤呈类圆形等低信号,灶肿瘤周围间质水肿区白质纤维束仍能在DTI的FA图上显像,DTI的FA图像对于脑白质纤维束显影的信号对比度明显优于常规的T1W图像.肿瘤病灶区和灶周水肿区与正常白质区的MD值比较差异均有统计学意义（均P＜0.05）,而肿瘤病灶区与灶周水肿区的MD值比较差异无统计学意义（P＞0.05）;3个区域的FA值比较差异均有统计学意义（均P＜0.05＝.结论 磁共振DTI技术可在活体清晰、无创、直观地显示脑胶质瘤与周围脑白质纤维束的关系,结合其他序列的MRI应用于脑胶质瘤的术前诊断,可以准确判断肿瘤和周围脑白质纤维束的毗邻关系,对脑胶质瘤术前诊断、手术方案设计以及术后神经功能障碍的预测与预防具有重要意义.

Application of diffusion tensor imaging of magnetic resonance imaging in the diagnosis of cerebral gliomas

Objective To investigate the clinical significance of diffusion tensor imaging of magnetic resonance imaging in the diagnosis of cerebral gliomas. Methods Diffusion tensor images were obtained in 23 patients with cerebral gliomas,meanwhile the routing T1-weighted(T1W) ,T2-weighted(T2W) ,contrast-enhanced T1W imaging, FLAIR imaging and diffusion tensor of the brain were acquired. Anatomic relationship between intracranial tumors and surrounding fibers was analyzed on fractional anisotropic(FA) map,color-coded directional map,three-dimensional white matter tractography. Results White matter fiber anatomy maps of the brain by means of FA maps of DTI at high resolution were successfully completed in all patients. The white matter tracts appeared as strongly hyperintense signal,while the grey matter presented an isointense area in contrast to the strongly hypointense signal of the CSF. Glioma boundaries were less sharper than on contrast-enhanced T1W images,but delineation could still be easily seen as hypointense lesion on FA map. The principal fiber tracts were well observed in all cases, including the tracts nearby the lesions. Apparently significant differences of MD were found in solid tumor,surrounding edema,compared with normal white matter regions(P ＜0.05). But there was no significant difference among solid tumor and surrounding edema region(P＞0. 05). There were significant differences of FA between solid tumor,surrounding edema and normal white matter region (P ＜0. 05). Conclusion The FA map of DTI offered the optimal visualization of white matter tracts. The combination of the DTI and other conventional MRI could accurately determine the tumor and surrounding proximity to the white matter fiber tracts in the diagnosis of cerebral glioma.