目的 应用DTI技术探讨脑小血 管病(cSVD)患者常规扫描表现正常白质 (NAWM)区微结构改变，及其与认识功能 障碍的相关性。方法 对23例cSVD患者 及13例条件相匹配的正常志愿者进行常 规MRI及DTI序列检查并完成MoCA评分， 后处理测量双侧额叶、顶叶、半卵圆中 心、胼胝体膝部及压部NAWM区的FA值 及ADC值，比较cSVD组与对照组间的差 异，并进一步分析cSVD组FA值及ADC值 与MoCA评分的相关性。结果 cSVD组双 侧额顶叶FA值较对照组减低，ADC值升 高，双侧半卵圆中心FA值较对照组减 低，其余两组间区别无统计学差异。 cSVD患者双侧额叶FA值下降最明显(右 侧(0.354±0.051)vs(0.398±0.027), P = 0 . 0 1 ， 左 侧 ( 0 . 3 6 5 ± 0 . 0 5 3 ) v s 0.405±0.035,P=0.00)。双侧额叶白质 的FA值与MoCA评分呈正相关(右侧额叶： r=0.43，P=0.01；左侧额叶：r=0.50， P=0.02)，ADC值与MoCA评分呈负相关， (右侧额叶：r=-0.40，P=0.03；左侧额 叶：r=-0.37，P=0.00)；其余部位FA值 及ADC值与MoCA评分无统计学意义的相关 性。结论 DTI能反映cSVD患者早期隐匿性 脑白质损伤，额叶白质DTI指标改变一定 程度可反映认知功能受损程度。

Objective To explore the occult damage of normal appearing white matter (NAWM) in patients with small vessel disease(cSVD) by using diffusion tensor imaging (DTI)technology, and its relationship with cognitive impairment. Methods Twentythree patients with cSVD and thirteen matched volunteers all received conventional MR scanning, DTI and montperllier cognitive function scale (MoCA) examination. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured symmetrically and compared among the two groups. Pearsoncorrelation analysis was used to determine the correlation between the FA，ADC and MoCA score in cSVD group. Results FA value on bilateral frontal and apical NAWM in cSVD group were lower than control group, and ADC value were higher than control group.The decreased FA value on bilateral centrum semiovale was demonstrated in cSVD group. FA value on bilateral frontal lobe decreased obviously, right (0.354±0.051)vs(0.398±0.027), P=0.01, left (0.365±0.053)vs(0.405±0.035),P=0.00).In cSVD group, the FA value of bilateral frontal NAWM were positively correlated with MoCA score (right: r=0.43, P=0.01, left: r=0.50, P=0.02), and the ADC value of bilateral frontal NAWM were negatively correlated with MoCA score(right: r=-0.40, P=0.03, left: r=-0.37, P=0.00). Conclusion The occult damage of normal appearing white matter (NAWM) can be detected using DTI. And DTI can reflect the severity of cognitive impairment in patients with cSVD.