轻度认知功能障碍弥散参数定量范围及与认知损伤程度的关系

Quantitative analysis of diffusion parameters and correlation with the clinical cognitive assessment of mild cognitive impairment

目的探讨轻度认知功能障碍(MCI)患者认知功能相关脑区弥散参数的定量大小及其与临床指标的相关性,为MCI的弥散张量成像(DTI)影像诊断提供参考指标。方法采用DTI检测纳入研究的21例MCI患者双侧海马、双侧海马旁回、双侧后扣带回、双侧额中回及双侧颞中回认知功能相关脑区弥散各向异性参数(FA)、平均弥散量(MD)的均值、标准差。计算脑区内FA、MD均值与MoCA、MMSE认知功能评分的相关性。结果定量确定了认知相关脑区内的FA、MD值及变化范围。MCI患者右侧后扣带回的FA值均值与MoCA、MMSE评分呈正相关;左侧海马、右侧额中回、左侧颞中回的FA值均值与MMSE呈负相关;左侧海马、左侧海马旁回、右侧颞中回的MD值均值与MMSE评分呈正相关;左侧海马旁回的MD值与MoCA评分呈正相关,上述相关性分析结果均具有统计学意义(P<0.05)。结论DTI各参数指标定量范围的确定可以为MCI的早期诊断提供一定的量化诊断依据;左侧海马、左侧海马旁回、右侧后扣带回、右侧额中回及双侧颞中回可能是MCI影像诊断重点关注的脑区。

Objective To ascertain the quantitative value and the range of the diffusion tensor imaging （DTI） pa- rameters of the mild cognitive impairment （MCI） related brain regions and the relationship with clinical cognitive assessment scores. Methods Twenty one MCI patients were enrolled in this study. Ten MCI related brain regions including bilateral hippocampus, parahippocampal gyrus, puposterior cingulate cortices, middle frontal cortices, and middle temporal cortices were selected as the region of interests （ROD. The mean and standard deviation （SD） values of the fractional an- isotropy （FA） and mean diffusivity （MD） in each ROI were calculated. Also, the correlation between the mean diffusion parameters and MoCA, MMSE were also analyzed. Results The quantitative mean and SD values of each ROI were obtained. Both MoCA and MMSE scores revealed significant positive correlations with the mean FA value of the right posterior cingulate cortex. Negative correlations were observed between MMSE and the mean FA values of the left hippocampus, right middle frontal cortex, and left middle temporal cortex. Also, the positive correlation were also found between MMSE scores and the MD values in the left hippocampus, left parahippocampal gyrus, right middle temporal cortex. A positive correlation between MMSE scores and the MD values in the left parahippocampal gyrus was also observed. All above correlation results were statistically significant （P〈0.05）. Conclusion The quantitative value and the range of FA and MD in cognitive related brain regions may provide significant value for DTI diagnosing to MCI disease.The regions including left hippocampus, left parahippocampal gyrus, right posterior eingulate cortex, right middle frontal cortex, and bilateral middle temporal cortices, which significantly correlated with the clinical assessment score.