磁共振扩散加权成像在胶质瘤术前分级中的应用研究

目的通过磁共振扩散加权成像研究肿瘤实性区域的组织扩散情况，探讨扩散加权成像在胶质瘤术前分级中的应用价值。方法回顾性分析手术病理证实的脑胶质瘤患者常规MRI、DWI检查资料，按照2000年WHO脑肿瘤分级标准，低级别胶质瘤（Ⅰ-Ⅱ级）22例，高级别胶质瘤（Ⅲ-Ⅳ级）17例。所有病例均术前行DWI扫描，在工作站构建ADC图，分别测量肿瘤实性区域和相应部位正常参照区域的ADC值，观察高级别胶质瘤组和低级别组肿瘤实性区域ADC值与正常对照的相互关系，并着重观察两组肿瘤各自与正常参照区域的相对（肿瘤／参照）ADC值之间的关系。低级别和高级别胶质瘤之间肿瘤实性区域各项比值的比较均采用两样本￡检验。结果高级别胶质瘤组肿瘤实性区域ADC值（1．27±0．20）×10^-3 mm^2／s较正常对照区（1．10±0．15）×10^-3mm^2/s稍高，两者之间具有统计学差异（P〈0．05）；而低级别胶质瘤组肿瘤实性区域ADC值（1．84±0．29）×10^-3 mm^2／s明显高于正常对照区（1．00±0．08）×10^-3 mm^2／s，具有显著性差异（P〈0．01）。结论高级别胶质瘤与低级别胶质瘤瘤体实性区域rADC值有显著性差异，这提示MRDWI有助于提高胶质瘤术前分级评价准确性。

Diffusion MR Imaging for Preoperative Evaluation of Tumor Grade in Gliomas

Objective To measure the diffusion-weighted imaging characteristics of solid regions of gliomas,emphasize on the role of DWI in preoperative evaluation of tumor grade in gliomas. Methods 39 patients with pathology-proved gliomas （17 cases,WHO Ⅲ- Ⅳ, high-graded;WHO Ⅰ- Ⅱ,lower-graded, 22 cases）were examined with DWI MR imaging. Apparent diffuse coefficients were measured on maps generated from DWI data of solid regions of tumors,and analogous locations in the contralateral WM corresponding to these areas. Changes in ADC in each type of tissue were compared across tumor types by using a two-sample t test. Results For high-grade gliomas, ADC in solid regions were（ 1.27 ± 0.20） ×10^-3 mm^2/s （P〈 0.05 ）. And for lower-grade gliomas, （1.84± 0.29） ×10^-3 mm^2/s（P〈 0.01 ）. The rADC had statistical significance（P〈 0.01 ）. Conclusion The difference in rADC in solid regions between high-grade ghomas and lower-grade ghomas is significant. These findings may indicate a role for diffusion imaging in the differentiation of high-grade gliomas and lower-grade on the basis of differences in diffusion levels in solid regions of tumors.