| Purpose To detect cerebral blood flow(CBF)in different stages of cognitive impairment in Parkinson's disease and compare normal cognitive function of parkinson's disease(PD-NC),mild cognitive dysfunction(PD-MCI)and dementia(PDD)patients by arterial spin labeling(ASL)magnetic resonance imaging(MRI)technology and to explore changes of the cerebral blood flow perfusion and its correlation with cognitive dysfunction.Method 20 PD-NC patients,22 PD-MCI patients,18 PDD patients and 20 healthy volunteers were recruited in the study.Conventional head MRI images and 3D ASL images covering the whole brain were obtained by 3.0T MRI scanner.Mini-mental state examination and Montreal cognitive assessment scale were examined to every subject.(1)Voxel-based analysis:Cerebral blood flow(CBF)was matched to the standardized brain space,and then REST software kit was used for statistical analysis of the differences in whole brain voxel level.Data was preprocessed by SPM12 software based on Matlab2013.Gray matter volume was as the covariate,one-way analysis of variance(ANOVA)method was used to compare among all groups,and two sample t test was done between every two groups to obtain abnormal perfusion brain regions.The results by Alphasim multiple comparison correction continuum element>24 voxel of the brain region and P<0.001 were defined as the difference statistically significant and then superimposed on the standard CH2 template.The MNI coordinates and peak values of each brain region were recorded.(2)The result of the PD-NC group,PD-MCI group,PDD group compared with NC group was saved as the template,and the brain regions in the template were considered as ROI by REST software.CBF value of ROI in every subject was extracted in the PD-NC group,PD-MCI group,PDD group and compared with MMSE,MoCA scores respectively by Spearman rank correlation analysis,P<0.05 for the difference was statistically significant.Result(1)Voxel-based statistical analysis showed that the perfusion difference of ANOVA among all groups was mainly manifested in bilateral cerebral hemispheres and cerebellar hemispheres.(2)The comparison between every two groups by two sample t test was as follows:? Compared with the NC group,decreased perfusion mainly in the bilateral insula,left superior temporal gyrus,left middle temporal gyrus and left precuneus were detected in the PD-NC group,indicating that although no obvious cognitive impairment was observed in the PD-NC stage,the perfusion in partial brain areas began to decrease,and the difference was statistically significant(P<0.001).? Compared with the NC group,decreased perfusion mainly in bilateral posterior central gyrus,bilateral superior frontal gyrus,bilateral middle frontal gyrus,left caudate nucleus,left putamen,left middle temporal gyrus,left fusiform gyrus,left middle occipital gyrus,and bilateral inferior cerebellar gyrus in the PD-MCI group,indicating that cortical and cerebellar perfusion could be decreased from the stage of PD-MCI,and the difference was statistically significant(P<0.001).? Compared with the NC group,extensive decreased perfusion in bilateral hemispheres and cerebellum were detected in the PDD group,indicating that progressive decreased perfusion was observed with the progression of the severity of cognitive impairment,and the difference was statistically significant(P<0.001).?Compared with the PD-NC group,decreased perfusion mainly in bilateral posterior central gyrus,left parietal gyrus,bilateral fusiform gyrus and bilateral superior cerebellar gyrus were detected in the PD-MCI group.The decreased perfusion was most obvious in parietal lobe,suggesting that the decreased perfusion in parietal lobe might be the biomarker for progression from PD-NC to PD-MCI,and the difference was statistically significant(P<0.001).? Compared with PD-MCI group,decreased perfusion mainly in bilateral cerebellum,precuneus,next time after cingulate gyrus,left superior temporal gyrus,left superior temporal gyrus,right amount last time,back in the left frontal and left parahippocampal gyrus were detected in the PDD group,especially the posterior cortex(precuneus and posterior cingulate)perfusion,indicating that the decreased posterior cortical perfusion might be the biomarker for progression from PD-MCI to PDD(P<0.001).(3)Spearman rank correlation analysis among abnormal perfusion brain area CBF value?cognitive scores revealed that? In the PD-NC group,the CBF values of bilateral insula,left superior temporal gyrus,left middle temporal gyrus and left precuneus were positively correlated with MMSE and MoCA scores(P<0.05).? In the PD-MCI group,the CBF values of bilateral posterior central gyrus,bilateral superior frontal gyrus,bilateral middle frontal gyrus,left caudate nucleus,left putamen,left middle temporal gyrus,left fusiform gyrus,left middle occipital gyrus and bilateral inferior cerebellar gyrus were positively correlated with MMSE and MoCA scores(P<0.05).? In the PDD group,the CBF values of bilateral cerebral hemisphere and cerebellar regions were positively correlated with MMSE and MoCA scores(P<0.05).Conclusion:(1)This study showed that CBF presented a progressive decrease in the process of cognitive function decline in PD,mainly manifested in the decreased perfusion in the parietal lobe and posterior cortex,but no increased perfusion area,suggesting that the decreased cerebral blood flow perfusion regions may provide important neuroimaging basis for the diagnosis of PD cognitive function decline.(2)Decreased cerebral perfusion regions in the process of cognitive decline of PD has a good correlation with cognitive scores,suggesting that decreased cerebral perfusion of PD may be the internal mechanism of cognitive impairment of PD. |
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