中文摘要：

目的 采用基于纤维束空间统计分析（TBSS）方法研究阿尔茨海默病（AD）患者脑白质微观改变,并探讨白质纤维损伤与认知功能下降的关系.方法 采集24例AD患者及24名对照组的弥散张量成像数据,通过TBSS方法寻找患者组白质微观结构差异的脑区,与简易精神状态检查（MMSE）得分进行相关性分析.结果 AD组各向异性分数（FA）值下降的白质区域有胼胝体、穹窿、左侧皮脊束、双侧大脑脚、小脑上脚、内囊、辐射冠、丘脑后辐射、矢状层（包括下纵束及额枕下束）、外囊、扣带、海马区纤维束、上纵束及钩束（均P＜0.05,无阈值簇增强校正）.平均扩散率（MD）值增加的白质脑区有穹窿、左侧海马区、双侧内囊、辐射冠、丘脑后辐射、矢状层（包括下纵束及额枕下束）、外囊、扣带、上纵束、额枕上束及钩束（均P＜0.05,无阈值簇增强校正）.MMSE评分与左侧矢状层的FA值呈正相关（r=0.535,P=0.007）,而与左侧矢状层（r=-0.427,P=0.037）、左侧上纵束（r=-0.424,P=0.039）、左侧钩束（r=-0.505,P=0.012）的MD值呈负相关.结论 AD患者存在广泛的白质结构损伤,半球内及半球间的连接均减弱.左侧大脑半球白质纤维的损伤可能与AD患者认知功能下降密切相关.

英文摘要：

Objective To observe microstructural changes of white matter in Alzheimer＆#39;s disease （AD）,and to find out the relationship between white matters lesion and declined cognition.Methods Twenty-four AD patients and 24 controls with normal cognition performed diffusion tensor imaging MR scan.Tract-based spatial statistical analysis （TBSS） was used to investigate microstructural change of white matter,and then its correlation with Mini-Mental State Examination （MMSE） scores was analyzed.Results Fractional anisotropy （FA） values were decreased in corpus callosum,fornix,left corticospinal tract,bilateral cerebral peduncle,superior cerebellar peduncle,internal capsule,corona radiata,posterior thalamic radiation,sagittal stratum including inferior longitidinal fasciculus and inferior fronto-occipital fasciculus,external capsule,cingulate gyrns,hippocampus,superior longitudinal fasciculus and uncinate fasciculus,while mean diffusivity （MD） values were increased in fornix,left hippocampus,bilateral internal capsule,corona radiata,posterior thalamic radiation,sagittal stratum including inferior longitidinal fasciculus and inferior fronto-occipital fasciculus,external capsule,cingulate gyrus,superior longitudinal fasciculus,superior fronto-occipital fasciculus and uncinate fasciculus （all P 〈 0.05,threshold-free cluster enhancement corrected）.MMSE scores had a positive correlation with decreased FA values of left sagittal stratum （r =0.535,P =0.007） and negative correlations with increased MD values of left sagittal stratum （r =-0.427,P =0.037）,left superior longitudinal fasciculus （r =-0.424,P =0.039） and left uncinate fasciculus （r =-0.505,P =0.012）.Conclusions There exist widespread white matter lesions in AD with impairment of white matter connections of intra-and inter-hemispheres.Impaired white matters in left hemisphere may have close relationships with cognition decline.