复发-缓解型多发性硬化全脑白质的扩散张量成像特征

Diffusion tensor imaging of whole brain natter in patients with relapsing-remitting multiple sclerosis

目的探讨复发-缓解型多发性硬化患者(relapsing-remitting MS,RRMS)大脑白质微观结构发生的异常改变。方法 17例RRMS患者与21例健康志愿者行全脑常规MRI及DTI成像,采用基于纤维束示踪的空间统计方法(tractbased spatial statistics,TBSS)对DTI数据进行处理分析,并对大脑内的主要白质纤维束进行ROI统计分析。结果与健康志愿者相比,RRMS患者各向异性参数(FA)几乎在所有被检区域内显著减低,平均扩散系数(MD)值也在多个区域内显著增高,并且TBSS的分析显示轴向扩散系数(AD)与径向扩散系数(RD)也在多个白质区域内显示异常增高。结论RRMS患者白质内同时存在轴突损坏和髓鞘缺失,而且本结果中发现不同纤维束内DTI参数的异变程度不同,进一步表明了脑内不同纤维束之间对MS的不同病理学影响的敏感性存在差异,同时也间接地反映了MS病理学的复杂性。

Objective To investigate the abnormal micro-structure changes of the brain white matter in patients with Relapsing-Remitting Multiple Sclerosis （RRMS）. Methods Seventeen patients with RRMS and 21 health volunteers were examined by routine Magnetic Resonance Imaging （MRI） and Diffusion Tensor Imaging （DTI） scans. The DTI data were processed and analyzed by Tract-Based Spatial Statistics（TBSS）. And the main brain white matter tracts were analyzed statistically in the Regions of Interests （ROI）. Results Contrast to the healthy volunteers, the fractional anisotropy （FA） values of the almost of the detected regions in the patients with RRMS decreased obviously, while the Mean diffusion coefficient （MD） values of the many of these regions raised remarkably. The analysis of TBSS revealed that the Axial diffusion coefficient （AD） and Radial diffusion coefficient （RD） elevated notably in many regions of white matter. Conclusion The axon damages and the myelin sheath deficiencies might present simultaneously in patients with RRMS. This study found that the abnormalities degrees of the DTI parameter varied in different fiber tracts, which further showed that the different brain fiber tracts were sensitive differently to the different pathological effects on MS. Meanwhile, the pathological complexity of MS was estimated indirectly.