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目的既往研究多是利用扩散张量成像(DTI)研究脑白质特性以评估遗忘型轻度认知障碍(aMCI)和阿尔茨海默病(AD)患者。文中应用DTI中的平均扩散率(MD)评估aMCI和AD患者灰质微观结构完整性的损伤特征,从而判断其转化规律。方法回顾性分析南京大学医学院附属鼓楼医院2014年1月至2016年12月期间30例符合Petersen标准的aMCI患者(aMCI组)、30例AD患者(AD组)以及30例正常对照组(CN组)测量的全脑灰质MD值,构建灰质水分子平均扩散率网络,计算小世界网络特性,并与神经心理学评分进行相关性分析。结果与CN组相比,aMCI和AD组的灰质水分子平均扩散率网络显示出异常的小世界特性,即聚集程度较高和路径长度较长,反映了灰质微结构的损伤,且aMCI患者网络的平均连接度低于CN组,但高于AD组,差异均有统计学意义(P<0.05)。包括双侧海马和边缘系统的11个枢纽脑区灰质MD值和蒙特利尔认知评估量表得分呈负相关(P<0.05)。结论 aMCI脑灰质的水分子扩散特征有助于发现AD前期患者,并反映神经退行性疾病脑微观结构的破坏。
Purpose Previous studies mostly used diffusion tensor imaging (DTI) to study white matter traits to assess patients with amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD). In this paper, the average diffusivity (MD) in DTI was used to evaluate the damage characteristics of gray matter integrity in aMCI and AD patients to determine the transformation rules. Methods A retrospective analysis was performed on 30 aMCI patients (aMCI group), 30 AD patients (AD group) and 30 normal controls (CN group) from January 2014 to December 2016 at Drum Tower Hospital, Nanjing University Medical College. Group), the average diffusivity network of gray matter was constructed, the characteristics of small-world network were calculated, and the correlations were analyzed with the neuropsychological score. Results Compared with CN group, the gray matter average diffusivity network of gray matter in aMCI group and AD group showed abnormal small-world characteristics, ie, higher aggregation degree and longer path length, which reflected the damage of gray matter microstructure, and the network of aMCI patients The average degree of connection was lower than CN group, but higher than AD group, the difference was statistically significant (P <0.05). MD values of gray matter in 11 hubs including bilateral hippocampus and limbic system were negatively correlated with the Montreal Cognitive Assessment Scale (P <0.05). Conclusion The diffusion of water molecules of aMCI in the gray matter of the aMCI can help to detect the patients with pre-AD and reflect the damage of brain micro-structure of neurodegenerative diseases.