基于multi-atlas QSM定量分析阿尔茨海默病脑基底核团异常铁沉积

Multi-atlas-based analysis of quantitative susceptibility mapping in evaluating abnormal iron deposition at brain basal nuclei in patients with Alzheimer’s disease

目的:基于多图谱(multi-atlas)的磁化率成像(QSM)定量分析,评估阿尔茨海默病(AD)患者大脑基底核团的异常铁沉积,并探讨其与认知功能改变的关系。方法:搜集在本院神经内科门诊就诊的符合NINCDS-ADRDA标准的34例AD患者的病例资料,男14例、女20例,年龄(67.9±7.7)岁。同期自社区招募年龄、性别和教育程度相匹配的34例健康志愿者(正常对照组),其中男12例、女22例,年龄(65.4±5.8)岁。所有被试行高分辨率三维容积T_(1)WI和多回波梯度回波序列MRI扫描。对多回波梯度回波序列进行图像重建得到QSM图像,然后利用MRICloud平台,进行基于QSM和T_(1)WI双通道(双对比度)的多图谱分析,自动分割脑基底核团并测量其磁化率值,比较两组间磁化率的差异,同时分析AD患者基底核团磁化率与简易精神状态量表(MMSE)评分的关系。结果:与正常对照组比较,AD患者双侧尾状核、右侧外侧苍白球、双侧壳核、双侧背侧丘脑、双侧丘脑底核及双侧红核的磁化率升高(P均<0.05,未校正);经多重比较矫正后,仅右侧壳核(P=0.002)和左侧背侧丘脑(P=0.001)的磁化率与对照组之间的差异有统计学(P<0.05,Bonferroni校正)。皮尔森相关分析显示,右侧壳核(r=-0.302,P=0.020)和左侧背侧丘脑(r=-0.319,P=0.014)的磁化率与MMSE评分呈显著负相关。结论:AD患者大脑深部基底核团的铁含量较健康人群显著增加,且与患者认知功能的下降具有相关性;基于multi-atlas的QSM定量分析方法可用于AD患者基底核团异常铁沉积的定量评估。

Objective:To evaluate abnormal iron deposition of deep grey matter nuclei and its relationship with cognitive function in Alzheimer’s disease(AD)using multi-atlas-based analysis of quantitative susceptibility mapping(QSM).Methods:Sixty-eight people were recruited in this study including 34 AD patients from outpatients of neurology department who matched NINCDS-ADRDA criteria and 34 age-,gender-and education years-matched normal controls(NC group)from local communities.In AD group,there were 15 males and 20 females with mean age of(67.9±7.7)years;and in NC group,there were 12 males and 22 females with mean age of(65.8±6.4)years.All subjects underwent MRI scan with high-resolution three-dimensional(3D)T_(1)-weighted and 3D multi-echo gradient echo(GRE)sequences.QSM images were reconstructed from multi echo GRE images.Multi-atlas approach based on the QSM and T_(1)WI was performed using MRI Cloud platform to obtain magnetic susceptibility values of the basal ganglia,which were automatically segmented.The differences of susceptibility values were compared between AD and NC using independent two-sample t-test.In AD group,the relationship between mini-mental state examination(MMSE)score and susceptibility value in the brain regions that had significant differences with NC were analyzed using Pearson correlation analysis.Results:The susceptibility values of bilateral caudate nucleus(CN),the right globus pallidus externus(GPe),bilateral putamen(Put),bilateral dorsal thalamus(dTh),bilateral subthalamic nucleus(STN)and bilateral red nucleus(RN)were significantly higher(all P<0.05,uncorrected)in AD patients than those of NCs.After multiple comparison correction,only the right putamen(P=0.002)and the left dorsal thalamus(P=0.001)showed significant difference with NC(P<0.05,Bonferroni corrected).Moreover,the susceptibility values of the right putamen(r=-0.302,P=0.020)and the left dorsal thalamus(r=-0.319,P=0.014)were negatively correlated with MMSE scores in AD patients.Conclusion:The iron content of the deep grey matter nuclei in AD patients were significantly higher than that in NC,which was also associated with a decline in cognitive function.Multi-atlas-based analysis of QSM can be used to quantitatively assess the abnormal iron deposition in brain gray matter nuclei in AD patients.