脑白质束扩散张量与阿尔茨海默病患者的神经心理学量表评分的多元线性回归分析

Linear Regression Analysis on Diffusion Tensor Imaging with Neuropsychological Study in Patients with Alzheimer' s Disease

目的应用线性回归方法,通过对阿尔茨海默病(AD)的相关脑白质束扩散张量分析,找出与AD患者神经心理学评分的相关关系并建立回归方程。资料与方法对20例轻度AD患者、30例中重度AD患者以及25名年龄相匹配的正常老年自愿者进行扩散张量成像(DTI)扫描。DTI采用单次激励平面回波成像(EPI)序列,扩散敏感梯度施加在25个不同方向,生成平均扩散系数(MD)、部分各向异性(FA)参数图,结合彩色向量图及纤维追踪图分别测定各白质束的参数值,包括双侧扣带束、上纵束、下纵束、下额枕束、钩束、穹窿体、胼胝体膝部及压部。利用多元线性回归分析,建立各DTI参数与简易智能量表(MMSE)评分的回归模型。结果对照组与轻度AD组比较仅穹窿体和左侧扣带束的FA值存在明显差异;轻度AD组与中重度AD组比较穹窿体、双侧钩束、扣带束、下纵束、胼胝体膝部及压部及右侧下额枕束的FA值均存在统计学差异。对照组与轻度AD组的MD值在穹窿体区存在统计学差异,而轻度AD组与中重度AD组在穹窿体、双侧钩束、下额枕束、左侧扣带束、右侧上、下纵束、胼胝体膝部及压部均存在MD值的显著差异。回归模型提示穹窿体和左侧扣带束的FA值与MMSE评分存在正线性相关关系,而与右侧扣带束的MD值呈负线性相关关系,回归方程为:MMSE=13.051+48.489 FA穹窿体+27.008FA左侧扣带束后部-3.074 MD右侧扣带束后部。结论AD患者的穹窿体、扣带束后部白质受累最为明显且与神经心理学评分相关,对于评价AD患者的病情及监测其进展情况有一定的临床应用价值。

Objective Using linear regression method,to investigate the relationship between diffusion tensor imaging（DTI） parameters of the brain white matters and neuropsychological scores in patients with Alzheimer＇s disease（AD）.Materials and Methods 20 mild AD patients,30 moderate to severe AD patients and 25 age-matched normal subjects were recruited in this study.All these subjects underwent a DTI examination.Diffusion-sensitizing gradient encoding was applied in 25 directions.By consulting the color-coded map and fiber tractography,the FA and the MD values of the white matters in different regions were measured,including the bilateral posterior cingulum（PC）,superior longitudinal fasciculus（SLF）,inferior longitudinal fasciculus（ILF）,inferior occipitofrontal fasciculus（IOF）,uncinate fasciculus（UNC）,fornix（Fx）,the anterior and posterior parts of corpus callusum（ACC,PCC）.Mean DTI values in each group were analyzed with ANOVA parametric test.The most influential parameters were estimated in AD group using multiple linear regression model method.Results Significant differences（P〈0.05） of FA value between the fornix and the left side of the posterior parts of cingulum were found in NC and mild AD group.By comparing mild AD group with moderate to severe group,the statistical differences of FA were showed in quite extensive regions,including Fx,bilateral UNC,PC,ILF,ACC,PCC and right side of IOF.With regard to the MD values,a significant higher value in Fx was found in mild AD group when compared with NC group（P〈0.01）.MD values in Fx,bilateral UNC,IOF,left PC,right side of SLF and ILF,ACC and PCC were evidently higher in moderate and severe AD group than that in mild AD group.The regression model showed that The FA values of Fx and the left PC showed positive relationship with MMSE scores,while a negative correlation was found between the MD value of the right side PC and MMSE scores.Regression formula was：MMSE=13.051＋48.489 FA value of Fx＋27.008 FA value in the left side of PC-3.074 MD value in right side of PC. Conclusion DTI alterations,especially in the fornix and the posterior parts of the cingulum,might be helpful for evaluating the severity of AD disease and could probably serve as a disease monitor.