Study Of Perfusion Changes In Alzheimer’s Disease And Parkinson’s Disease Based On Three-dimensional Arterial Spin Labeling MRI

Objective:To investigate the similarities and differences of brain blood perfusion between Alzheimer’s disease(AD)and Parkinson’s disease with dementia(PDD)patients by threedimensional pseudo-continuous arterial spin labeling(3D-p CASL)magnetic resonance imaging(MRI),and the potential associations between cerebral perfusion and cognitive impairment.Materials and Method:From July 2018 to December 2019,a total of 24 AD subjects and 26 PDD patients were recruited from the outpatient or inpatient population of the Department of Neurology Northern Jiangsu People’s Hospital).In addition,36 normal control group(NC group)were collected and included in this study.MMSE and MOCA scores were used to evaluate the cognitive function of the subjects,and UPDRS-III and H&Y scores were used to evaluate the motor function of the patients with PDD.All subjects underwent routine brain magnetic resonance imaging scan to exclude organic lesions,and then whole brain3 D pseudo-continuous ASL sequences were scanned.The CBF maps were preprocessed by SPM12 software.One-way analysis of covariance(ANCOVA)was used to compare the three groups,and two-sample t test were performed to detect the differences of local cerebral perfusion between every two groups.CBF values of brain regions with statistical differences in perfusion between AD group and PDD group were extracted from DPABI(V4.1)software,and Pearson correlation analyses were performed between the CBF values in these regions and clinical data.Receiver operating characteristic(ROC)analysis was constructed to ascertain the recognition capacity efficacy of regional CBF to discriminate AD from PDD patients.Results:Analysis of CBF showed largely overlapped perfusion changes between AD and PDD group when compare each group with controls,respectively,that are increased perfusion mainly located in bilateral basal ganglia and fronto-parietal association cortices,meanwhile decreased perfusion generally in parieto-temporal cortex,prefrontal cortex and precuneus.However,there are distinct perfusion patterns for the comparison between AD and PDD.AD patients embrace more extensive perfusion defects in cognitive-related areas than PDD patients,whereas PDD involve more perfusion defects in motor control related areas than AD.In AD group,the CBF of the right inferior parietal lobule(IPL)were positively correlated with the MMSE scores(P=0.033,r=0.442),and the CBF of the right precuneus were positively correlated with the memory scores(P=0.049,r=0.406).The CBF of right putamen in PDD group showed positive relationship with the UPDRSIII scores(P=0.017,r=0.214).ROC curve analysis results showed that the CBF values in the regions with statistically significant difference between AD and PDD groups provided good values of sensitivity and specificity(sensitivity from 81% to 96 %,specificity from63% to 88 %),the area under the curve was from 0.796 to 0.856,indicating good diagnostic accuracy.Conclusion:Our study suggests that hemodynamic alterations is an important factor in mediating the development of dementia,and that AD and PDD share similar cerebral hemodynamic damage processes,suggesting that AD and PDD may have a common hemodynamic mechanism.Meanwhile,the divergences of perfusion features between AD and PDD could imply respective preferential characteristics in terms of cognition and motor deficiencies.Objective:To analyze the changes of cerebral perfusion in Parkinson’s disease(PD)patients with different subtypes and their similarities and differences.Materials and Method:From July 2018 to December 2019,53 PD patients were recruited in this study,all of whom were outpatients or inpatients in the Department of Neurology(Northern Jiangsu People’s Hospital).The PD patients were classified into tremor dominant subtype(TD,n=26)and gait disorder subtype(PIGD,n=27)subtypes according to motor symptoms.In addition,35 normal control group(NC group)with matched age,sex and education level were collected and included in this study.MMSE score was used to evaluate the cognitive function of the subjects,and UPDRS-III and H&Y scores were used to evaluate the motor function of PD patients,then the TD score and PIGD score of the two subtypes were calculated according to UPDRS-III.All subjects underwent routine brain MRI scan to exclude organic lesions,and then underwent whole brain 3D pseudo-continuous ASL sequences were scanned.The absolute CBF maps were extracted using Functool software,and were preprocessed by SPM12 software.ANCOVA was used to compare the three groups,and two-sample t test were performed to detect the differences of local cerebral perfusion between every two groups.CBF values of brain regions with statistical differences in perfusion between TD group and PIGD group were extracted from DPABI(V4.1)software,and Pearson correlation analyses were performed between CBF values in these regions and clinical data.Results:Compared with normal controls,TD group showed increased perfusion in left parahippocampal gyrus,left fusiform gyrus,left precentral gyrus,bilateral thalamus,and bilateral cerebellum,while decreased perfusion in right temporal pole(middle and superior temporal gyrus),and right middle frontal gyrus(P<0.05).Compared with normal controls,PIGD group showed increased perfusion in left hippocampus,left parahippocampal gyrus,left fusiform gyrus,left precentral gyrus,left paracentral lobule and bilateral thalamus,while decreased perfusion in left inferior temporal gyrus,and right middle frontal gyrus(P<0.05).Compared with PIGD group,the TD group showed increased perfusion in right cerebellum and the left precentral perfusion was decreased(P<0.05).Additionally,CBF values of the left precentral gyrus and right cerebellum 8 region was positively correlated with TD scores in the TD group(r =0.397 and 0.541,P<0.05),and CBF values in right middle frontal gyrus was positively correlated with MMSE scores in the PIGD group(r=0.411,P=0.04).Conclusion:PD patients with different motor subtypes had distinct perfusion patterns.The perfusion damages of TD patients mainly existed in the brain areas associated with cerebello?thalamo?cortical(CTC)circuit,while the PIGD patients presented perfusion damages mainly in the striatal?thalamo?cortical(STC)circuit.The respective characteristic perfusion patterns of the subtypes of PD implied complexity in the pathophysiological mechanisms,and could contribute to the different clinical signs.