| Objective:To investigate the distribution of brain regions that may be affected in the conversion of Mild Cognitive Impairment(MCI)to Alzheimer’s Disease(AD),and the value of combined imaging index of multiple brain regions on diagnosis and identification of AD and MCI by using resting-state functional magnetic resonance imaging(rs-fMRI).Methods:A total of 84 subjects including 29 AD patients,28 MCI patients,and 27 normal controls(NC)from Nanchong communities were recruited in our study.All the subjects were required to complete a systemic neuropsychological assessment and rs-fMRI scan.The spontaneous neural activity of brain was evaluated by the amplitude of low-frequency fluctuation(ALFF).A one-way analysis of variance(ANOVA)followed by two-sample t test post hoc analyses were performed to determine the influence of cognitive deficit on ALFF,and identify the corresponding brain regions,the correlation coefficient between the ALFF values of differential brain regions and the behavioral scales were calculated.In addition,ALFF value from a single brain region or integrate ALFF information of multiple brain regions was applied to classify AD,MCI from controls.The comparison of the sensitivity and specificity between different classification approaches was also conducted.Result:1.Significantly different in age and education were detected among AD,MCI,and NC.2.The ANOVA analysis showed significantly different ALFF among the three groups in bilateral precuneus/posterior cingulate cortex,bilateral parahippocampal gyrus,right lingual gyrus,right supramarginal gyrus,right superior parietal lobule,right inferior parietal lobule,right middle temporal gyrus and right inferior temporal gyrus.Compared with NC,the ALFF values of AD were significantly decreased in the bilateral precuneus/posterior cingulate cortex,right supramarginal gyrus,right angular gyrus,right superior parietal lobule and right inferior parietal gyrus;the ALFF values of MCI were significantly decreased in the bilateral supplementary motor area,bilateral paracentral lobule,bilateral precuneus/posterior cingulate cortex,right supramarginal gyrus,right superior parietal lobule and right inferior parietal lobule.Besides,relative to MCI,further decreased ALFF was also observed in the right middle temporal gyrus,right inferior temporal gyrus,and bilateral precuneus/posterior cingulate coretx in AD patients,and increased in the left paracentral lobule and left middle temporal gyrus.3.The receiver operating characteristic(ROC)analysis revealed that the multiple brain regions classification approach of AD could reach a sensitivity of 81.48%and a specificity of 78.57%,with an area under ROC of 0.817,which was significantly larger than the highest sensitivity and specificity of the method with single brain region of 66.67%and 75.00%.The best sensitivity and specificity of multiple brain regions combined diagnosis of MCI was 81.48%,82.15%,with the area under ROC of 0.823,which was significantly larger than the highest sensitivity and specificity of the method with single brain region of 62.96%and 89.29%.And the optimal sensitivity and specificity of multiple brain regions combined identification of AD and MCI was 92.59%,75.00%,with the area under ROC of 0.856,significantly greater than the highest sensitivity and specificity of 85.19%,67.86%for differential diagnosis of single brain region.Conclusion:1.Consistent alterations in spontaneous activity were found in the default mode(posterior cingulate cortex,supramarginal gyrus)and executive control(inferior parietal lobule,superior parietal lobule)networks both in AD and MCI patients.2.More aberrant ALFF was also observed in the middle temporal gyrus,inferior temporal gyrus and posterior cingulate cortex in AD relative to MCI patients,which may play an important role in the transformation from MCI to AD.3.Multiple brain regions classification approach yielded improvement in accuracy over using single region independently. |
PDF Full Text Request