轻度认知障碍患者背外侧前额叶白质的DTI研究

DTI Study of the White Matter of Dorsalateral Prefrontal Cortex in Patients with Mild Cognitive Impairment

目的用扩散张量成像(DTI)方法研究轻度认知障碍(MCI)患者背外侧前额叶白质的扩散特性,并探讨该区域可能的病理改变及DTI的临床诊断价值。资料与方法对17例MCI患者和18名年龄、性别和受教育程度相匹配的正常老年人进行全脑DTI扫描,测量其双侧背外侧前额叶白质的各向异性分数(FA)值、平均扩散率(MD)值和本征向量值(λ1、λ23),对两组数据进行统计学分析。结果MCI组两侧大脑半球背外侧前额叶白质的FA值较正常对照组减低而λ23值升高,且有显著的组间差异,而MD值和λ1值没有显著差异。结论MCI患者背外侧前额叶白质的FA值显著减低和λ23值升高,反映了MCI患者特定认知相关脑区白质微结构的早期病理改变,在MCI的诊断中具有较好的应用价值。

Objective To evaluate the diffusion characteristics of the white matter of dorsalateral prefrontal cortex（DLPFC）in patients with mild cognitive impairment （MCI） using DTI,and discuss its probable pathologic change and the diagnostic value of DTI.Materials and Methods Whole brain DTI were obtained in 17 MCI patients and 18 matched normal ageing elderly volunteers. Regions of interest were drawn in bilateral DLPFC white matter,and the fractional anisotropy （FA）,mean diffusivity （MD） and eigenvectors （λ1,λ23） were measured to compare statistically between the two groups.Results The FA values of bilateral DLPFC white matter were significant lower and the λ23 were significant higher in MCI patients than that in control subjects. There was no significant difference in MD values and λ1 in bilateral DLPFC between the two groups.Conclusion The decreased FA value and the increased λ23 in DLPFC white matter in MCI patients reflect the early ultrastructural changes in the cognition related brain area,it may be helpful in the early diagnosis of MCI.