轻度认知功能障碍合并腔隙性梗死患者脑白质完整性磁共振扩散张量成像研究

目的：使用磁共振(magnetic resonance，MR)扩散张量成像(diffusion tensor imaging，DTI)评价轻度认知功能障碍(mild cognitive impairment，MCI)合并腔隙性梗死(lacunar infarctions，LI)患者脑白质完整性及其与认知功能的相关性。方法：前瞻性纳入26例MCI患者，行头颅MR检查发现合并陈旧性LI者14人(MCI-LI组)，不合并陈旧性LI者12人(MCI-non LI组)，同期招募16位健康志愿者作为正常对照(normal control，NC)组。受试者均完成认知功能评估及头颅DTI检查。比较3组间DTI参数差异，采用多元线性逐步回归法确定DTI参数与认知功能的相关性。结果：MCI-LI组较MCI-non LI组扣带束左侧海马、胼胝体束额部、右下额枕束和右颞叶上纵束等白质纤维束的各向异性分数(fractional anisotropy，FA)值显著降低(P<0.05)，而平均扩散率(mean diffusivity，MD)值显著升高(P<0.05)。MCI-LI组扣带束右扣带回FA值与日常生活能力评估量表(Activity of Daily Living Scale，ADL)评分显著相关(B=–50.2，95% CI：–77.7~–22.7，P=0.003)。MCI-LI组左侧丘脑前辐射FA值(B=443.8，95% CI：222.9~664.8，P=0.001)及左下纵束MD值(B=–318.5， 95% CI：–534.7~–102.3，P=0.009)与韦氏数字符号测验(Wechsler Digit Symbol Substitution，WDSS)评分显著相关。MCI-LI组左颞叶上纵束FA值与数字广度倒背(Backward Digit Span，BDSP)评分显著相关(B=12.5，95% CI：1.5~23.4，P=0.030)。 结论：MCI合并LI患者脑白质完整性较MCI不合并LI患者明显减低，MCI合并LI患者认知功能与部分脑白质DTI参数之间存在相关性。

White matter integrity in patients with mild cognitive impairment complicated with lacunar infarctions by diffusion tensor imaging

Objective: To evaluate the white-matter integrity and its correlation with cognitive function in patients with mild cognitive impairment (MCI) complicated with lacunar infarctions (LI) by diffusion tensor imaging (DTI) of magnetic resonance (MR). Methods: Twenty-six patients with MCI were selected including 14 patients with combined LI and 12 patients without combined LI, and 16 healthy volunteers were recruited as normal control. All subjects completed cognitive function assessment and DTI sequence of MR. Factional anisotropy (FA) and mean diffusivity (MD) values among the MCI with LI group (MCI-LI), the MCI without LI group (MCI-non LI), and the normal control group (NC) were compared, and the correlation between DTI parameters and cognition was determined by multiple linear stepwise regression. Results: Compared with the MCI-non LI group, the FA values were significantly decreased (P<0.05) and MD values were significantly increased (P<0.05) in the white matter fiber bundles (such as the left hippocampus of the cingulate tract, the frontal fascicle of the corpus callosum, the right inferior frontal occipital fascicle, and the right superior longitudinal fascicle) in the MCI-LI group. In the MCI-LI group, the FA value of right cingulate gyrus was significantly correlated with Activity of Daily Living Scale (ADL) score (B=–50.2, 95% CI –77.7 to –22.7, P=0.003); the FA value of left anterior thalamic radiation (B=443.8, 95% CI 222.9 to 664.8, P=0.001) and MD value of left inferior longitudinal tract (B=–318.5, 95% CI –534.7 to –102.3, P=0.009) were significantly correlated with Wechsler digit symbol substitution (WDSS) score; the FA value of left superior temporal lobe longitudinal tract was significantly correlated with Backward Digit Span (BDSP) score (B=12.5, 95% CI 1.5 to 23.4, P=0.030). Conclusion: The integrity of white matter is significantly destroyed in MCI patients with LI than that in MCI patients without LI, and there is a correlation between cognitive function and DTI parameters in some white matter tracts in MCI patients with LI.