阿尔茨海默病轻度认知障碍患者转化过程基线期静息态功能MRI研究

Resting-state functional MRI study at the baseline in mild cognitive impairment converting to Alzheimer＆#39;s disease

目的 探讨源于阿尔茨海默病（AD）的轻度认知障碍（MCI）向AD痴呆转化过程中,各组基线期静息态功能磁共振（rs-fMRI）的影像学差异,研究转化型MCI脑功能变化与神经心理评分的相关性,以期探索可能的预测转化的rs-fMRI影像学标记物.方法 纵向观察MCI患者27例,正常对照组（NC）31名,在基线期和随访期分别进行神经心理测评及rs-fMRI影像数据采集,应用功能连接强度（FCS）的方法获得全脑维度数据.MCI转化组（MCI-c）、MCI未转化组（MCI-nc）与NC组受试者年龄、受教育年限、各项神经心理学测评分数组间差异采用方差分析;3组间性别的差异采用X2检验进行比较,两次数据采集的时间间隔采用秩和检验进行组间差异的比较.3组间FCS的差异采用一般线性模型分析,采用相关分析评估具有组间差异脑区的FCS值与神经心理评分的相关性.结果 （1）基线期在双侧角回、双侧眶额皮层、右侧中央前回、左侧旁中央小叶、左侧楔前叶、右侧梭状回、右侧枕中回、右侧枕上回、左侧小脑等脑区组间差异有统计学意义.（2）与MCI-nc相比,MCI-c在双侧角回、右侧枕中回、右侧枕上回、右侧枕下回、右侧梭状回、左侧楔前叶、左侧旁中央小叶存在FCS下降,簇大小分别为149、114、186、56、48、33、38、102个体素,P值均〈0.05.（3）基线期MCI-c组受试者在右侧角回的FCS与简易智能精神状态量表（MMSE）存在负相关（r=-0.561,P=0.017）.结论 MCI-c与MCI-nc基线期的rs-fMRI影像学数据有利于观察MCI患者向AD痴呆转化前的影像学特征,右侧角回的FCS变化有望成为潜在的预测MCI向AD痴呆转化的rs-fMRI影像学标记物.

Objective To explore the features of resting state functional magnetic resonance imaging （rs-fMRI） in the patients with mild cognitive impairment （MCI） after during the process of converting to Alzheimer＇s disease （AD） dementia. To study the correlation of the brain function imaging and neuropsychological scores in converted MCI subjects with the purpose of finding the potential functional biomarkers which may predict the conversion of MCI to AD dementia in short term using resting state functional MRI. Methods Twenty-seven patients with MCI and 31 age, gender and years of education matched normal controls （NC） were enrolled in this study and neuropsychological assessment and rs-fMRI data were acquired respectively at the baseline and follow-up. Functional connectivity strength （FCS） analyses were used to assess the functional differences among the groups of MCI-converters （MCI-c） , MCI-non converters （MCI-nc） and NC. Variance analyses were used to compare the group differences in age, years of education and each neuropsychological assessment. In addition, Chi-squared test was used to compare group differences in gender. Then, Kruskal-Wallis test was used to compare group differences in the interval time of twice data collection. Group differences in FCS values were analyzed by general linear model. Finally, correlation analyses were used to evaluate the relationships between the FCS values of the brain regions with group differences and neuropsychological assessment scores in MCI patients. Results （1） Significant group differences of FCS among the MCI-c, MCI-nc and NC groups were observed in bilateral angular gyri, bilateral orbitofrontal cortex, right precentral gyrus, left paracentral lobule, left precuneus, right fusiform, right middle occipital gyrus, right superior occipital gyrus, left cerebellum. （2） The MCI-c showed decreased FCS in bilateral angular gyri, right middle occipital gyrus, right superior occipital gyrus, right inferior occipital gyrus, right fusiform, left precuneus, and left paracentral lobule, as compared to MCI-nc, the cluster was 149, 114, 186, 56, 48, 33, 38 and 102 voxels, respectively;P〈0.05, respectively. The correlation analysis showed that the FCS values of the right angular gyrus were negative correlated with the MMSE scores （r=-0.561, P=0.017） . Conclusions This study revealed that the comparison of rs-fMRI imaging data between MCI-c and MCI-nc at baseline is of great benefits in analysing the imaging characteristics of patients during converting from MCI to AD. The feature of FCS in rs-fMRI in right angular gyrus might serve as early indicators for the dysfunction and progression from MCI to AD.