Miloushev V Z, Chow D S, Filippi C G
From the Department of Diagnostic Radiology, Columbia University, New York, New York.
AJNR Am J Neuroradiol. 2015 Feb;36(2):302-8. doi: 10.3174/ajnr.A4097. Epub 2014 Sep 4.
Diffusion tensor metrics are potential in vivo quantitative neuroimaging biomarkers for the characterization of brain tumor subtype. This meta-analysis analyzes the ability of mean diffusivity and fractional anisotropy to distinguish low-grade from high-grade gliomas in the identifiable tumor core and the region of peripheral edema.
A meta-analysis of articles with mean diffusivity and fractional anisotropy data for World Health Organization low-grade (I, II) and high-grade (III, IV) gliomas, between 2000 and 2013, was performed. Pooled data were analyzed by using the odds ratio and mean difference. Receiver operating characteristic analysis was performed for patient-level data.
The minimum mean diffusivity of high-grade gliomas was decreased compared with low-grade gliomas. High-grade gliomas had decreased average mean diffusivity values compared with low-grade gliomas in the tumor core and increased average mean diffusivity values in the peripheral region. High-grade gliomas had increased FA values compared with low-grade gliomas in the tumor core, decreased values in the peripheral region, and a decreased fractional anisotropy difference between the tumor core and peripheral region.
The minimum mean diffusivity differs significantly with respect to the World Health Organization grade of gliomas. Statistically significant effects of tumor grade on average mean diffusivity and fractional anisotropy were observed, supporting the concept that high-grade tumors are more destructive and infiltrative than low-grade tumors. Considerable heterogeneity within the literature may be due to systematic factors in addition to underlying lesion heterogeneity.
扩散张量指标是用于脑肿瘤亚型特征化的潜在活体定量神经影像生物标志物。本荟萃分析分析了平均扩散率和分数各向异性在可识别的肿瘤核心和周围水肿区域区分低级别与高级别胶质瘤的能力。
对2000年至2013年间有关世界卫生组织低级别（I、II级）和高级别（III、IV级）胶质瘤的平均扩散率和分数各向异性数据的文章进行荟萃分析。采用比值比和平均差对汇总数据进行分析。对患者水平的数据进行受试者工作特征分析。
与低级别胶质瘤相比，高级别胶质瘤的最小平均扩散率降低。与低级别胶质瘤相比，高级别胶质瘤在肿瘤核心的平均扩散率值降低，而在周边区域升高。与低级别胶质瘤相比，高级别胶质瘤在肿瘤核心的FA值升高，在周边区域降低，且肿瘤核心与周边区域之间的分数各向异性差异减小。
最小平均扩散率在世界卫生组织胶质瘤分级方面存在显著差异。观察到肿瘤分级对平均扩散率和分数各向异性有统计学显著影响，支持高级别肿瘤比低级别肿瘤更具破坏性和浸润性的概念。文献中存在相当大的异质性，除了潜在病变异质性外，可能还归因于系统因素。
