目的：应用弥散张量成像（DTI）技术探讨脑白质疏松症（LA）患者在胼胝体部位的脑白质微结构改变与其认知功能障碍的关系。方法对2011年7月至2012年7月就诊于首都医科大学附属北京朝阳医院神经内科门诊的27例LA患者和23名年龄、性别、受教育程度相匹配的健康老年人（对照组）进行认知功能神经心理测验，并采集DTI数据，测量胼胝体膝部和压部受损脑白质的各向异性分数（FA）、表观弥散系数（ADC），并与认知功能进行相关性分析。结果（1）LA患者在MoCA评分上显著低于对照组[（20.1±4.5）分和（26.0±1.1）分，t＝10.01，P＜0.05]。LA患者还表现为Stroop色词干扰测验B[（68.3±15.0）s和（42.9±4.8）s，t＝8.02，P＜0.05]、Stroop色词干扰测验C[（150.2±43.6）s和（64.7±9.1）s，t＝7.70，P＜0.05]、连线测验 A[（71.6±14.7）s 和（32.0±6.9）s，t＝10.82，P＜0.05]、连线测验 B[（120.4±17.8）s和（83.0±6.3）s，t＝10.00，P＜0.05]、数字符号测验成绩[（24.8±6.5）个和（37.1±4.6）个，t＝7.19，P＜0.05]显著差于对照组。（2）与对照组相比，LA组胼胝体膝部（0.751±0.133和0.883±0.035，t＝10.31， P＜0.05）及压部（0.851±0.076和0.927±0.047，t＝8.09，P＜0.05）FA值较对照组降低，胼胝体膝部/压部ADC值[（0.818±0.148）×10-3 mm2/s和（0.677±0.038）×10-3 mm2/s，t＝9.10，P＜0.05/（0.828±0.078）×10-3 mm2/s 和（0.611±0.051）×10-3 mm2/s，t＝4.61，P＜0.05]较对照组增加，两组间差异存在统计学意义。（3）相关性分析得出，LA患者在胼胝体膝部FA值与连线测验B成绩呈负相关（r＝-0.475，P＝0.022），与数字符号测验成绩呈正相关（r＝0.694，P＜0.001）。LA患者在胼胝体膝部ADC值与MoCA评分（r＝-0.477，P＝0.021）和数字符号测验成绩呈负相关（r＝-0.607，P＝0.002）。LA患者在胼胝体压部FA值与Stroop色词干扰测验B成绩呈负相关（r＝-0.416，P＝0.048）。结论 LA患者存在显著认知功能障碍，尤其是执行功能障碍。DTI技术可反映LA患者胼胝体白质损害，且这种白质损害与认知功能密切相关。%Objective To investigate the relationship between loss of white matter integrity in corpus callosum and the cognitive impairment in patients with leukoaraiosis(LA) using the technique of diffusion tensor imaging(DTI). Methods Twenty-seven leukoaraiosis patients with LA and 23 age, gender-matched healthy subjects were recruited from the department of Neurology, Beijing Chaoyang Hospital, Capital Medical University between July 2011 and July 2012. All the participant underwent the neuropsychological tests and MRI examinations such as diffusion tensor imaging(DTI). For each participant, fractional anisotropy(FA) and apparent diffusion coefficient(ADC) were measured in both the splenium and genu of the corpus callosum. The relationship between the parameters of DTI and cognitive function were calculated. Result (1) The patients with LA were found with worse performance of Montreal Cognitive Assessment (MoCA) compared with healthy controls(20.1±4.5 vs. 26.0±1.1, t=10.01, P<0.05), the performances of Stroop-B test[(68.3±15.0)svs. (42.9±4.8)s, t=8.02, P<0.05], Stroop-C test[(150.2±43.6)svs.(64.7±9.1)s, t=7.70, P<0.05], Trail making test-A(TMT-A) [(71.6±14.7) s vs.(32.0±6.9) s , t=10.82, P<0.05], Trail making test-B (TMT-B)[(120.4±17.8) s vs. (83.0±6.3)s, t=10.00, P<0.05], Digit-symbol test (DST)(24.8±6.5 vs. 37.1±4.6, t=7.19, P<0.05) were found worse than control group. (2) Compared with control group, the FA is significantly reduced in both the splenium(0.751±0.133 vs. 0.883±0.035, t=10.31, P<0.05) and genu(0.851±0.076 vs. 0.927±0.047, t=8.09, P<0.05) of the corpus callosum in LA group, and the ADC was significantly increased[(0.818±0.148) ×10-3 mm2/s vs.(0.677±0.038)×10-3 mm2/s, t=9.10, P<0.05]/[(0.828±0.078)×10-3 mm2/s vs.(0.611±0.051) ×10-3 mm2/s, t=4.61, P<0.05]. (3) There was a negative relationship between the performance of TMT-B and the FA in the genu of corpus callosum(r=-0.475, P=0.022). We also found a positive relationship between the performance of DST and the FA in the genu of corpus callosum(r=0.694, P=0.000). Besides, a negative relationship between the MoCA and the ADC in genu of CC(r=-0.477, P=0.021), and a negative relationship between the performance of DST(r=-0.607, P=0.002) were also found. There was a negative relationship between Stroop-B and the FA in the splenium of corpus callosum(r=-0.416, P=0.048). Conclusion Our findings demonstrate patients with LA were closely correlated to cognitive impairment, especially in executive function. DTI can detect the impairment of white matter integrity of corpus callosum in patients with LA, which is closely correlated with cognitive function.
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