磁共振弥散张量成像在脑胶质瘤手术前后的临床应用价值

目的 探讨3.0T 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手术前后中的临床应用价值.方法 对24例脑胶质瘤患者行常规MRI及DTI检查,原始数据采集后传入工作站,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8例高级别胶质瘤肿瘤病灶区、灶周水肿区及正常白质区的平均弥散系数(MD值)、各向异性指数图(FA值).分析肿瘤与相邻脑白质纤维束的解剖关系,并对患者手术前后的临床症状进行评价.结果 16例Ⅰ～Ⅱ级胶质瘤推移相邻脑白质纤维束,患者术后临床症状明显改善;8例Ⅲ～Ⅳ级胶质瘤浸润破坏相邻脑白质纤维束,患者术后临床症状未明显改善.肿瘤病灶区和灶周水肿区与正常白质区的MD值比较差异有统计学意义(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(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,DTI的MD值和FA值可区分高级别胶质瘤肿瘤病灶区、灶周水肿区及正常白质区.DTI技术对脑胶质瘤术前治疗方案的确定以及手术风险和患者临床预后的预测具有重要的应用价值.

Application of diffusion tensor imaging in preoperation and postoperation patients of glioma with 3.0 Tesla MRI

Objective To investigate the clinical usefulness of diffusion tensor imaging(DTI) in demonstrating between gliomas and surrounding fibers.Methods 24 patients of glioma (WHO grade: grade Ⅰ-Ⅱ 16 cases; grade Ⅲ-Ⅳ 8 cases) were examined using DTI and conventional contrast-enhanced MRI of 3.0T MRI scanner(GE company, America). After the initial data acquisition introduced into workstation, image analysis was performed with the use of functool software. Mean diffusivity (MD) and fractional anisotropy (FA) values were measured in regions of solid tumor, surrounding edema and normal white matter of the high grade cerebral gliomas.Differences in these values among the tissues were assessed on the high grade cerebral gliomas. Anatomic relationship between intracranial tumors and surrounding fibers was analysed on fractional anisotropic (FA) map, color-coded directional map, three-dimensional white matter tractography. All patients′ symptoms were evaluated preoperative and postoperative respectively.Results The DTI patterns altered by the tumor were categorized as follows: displacement, infiltration and destruction. The tractography showed that the main influence in 16 cases of grade Ⅰ-Ⅱ glioma on adjacent white matter tracts was displacement, but infiltration and destruction were also revealed. The patients have definite improvement in symptoms. The destruction and infiltration of fiber tracts could be seen in all edema regions around grade Ⅲ-Ⅳ gliomas in 8 cases. The patients have not definite improvement in symptoms. 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).Conclusions The DTI offered the optimal visualization of white matter tracts. DTI plays an important role in demonstrating relationship between gliomas and neighboring fibers. MD and FA values could be used to distinguish normal white matter from solid tumor and surrounding edema region of high grade glioma. The application of DTI in preoperation plays an guidance role in making microsurgery plans and the evaluation of brain functional recovery in postoperation. DTI should be of great value in the microsurgical planning as well as estimation and reduction of potential postoperative neurological deficits for the cerebral gliomas resection.