Association Between Cognitive Function And Brain Iron Deposition In Patients Of MCI、AD And VCI

Objective:Intracranial scans using suscepitibility weighted imaging(SWI)were performed to distinguish the difference of phase values in specific areas of the brain in patients with Alzheimer’s disease(AD),amnestic mild cognitive impairment(MCI),and ischemic vascular cognitive impairment(VCI)and the healthy control.The correlation between phase values and MMSE scores was analyzed and the diagnostic value of iron deposition in cognitive impairment was discussed.Method:Patients with cognitive impairment who were diagnosed in the neurology clinic or inpatient department of the First Affiliated Hospital of Soochow U niversity from January 2018 to December 2019 were collected and scored on relevant cognitive scales,including the Mini-Mental State Examination(MMSE),Montreal Cognitive Assessment(MoCA),Alzheimer’s disease Assessment Scale Cognitive part(ADAS-Cog),Activity of Daily Living Scale(ADL),Clinical Dementia Rating Scale(CDR),Hachinski Ischemic Score(HIS),Hamilton Depression Scale(HAMD),Frontal Assessment Battery(FAB).Contraindications eliminated,all patients underwent SWI examinations in the Imaging Department of the First Affiliated Hospital of Soochow University,and measured the phase shift values(x)of bilateral caudate nucleus head,putamen,globus pallidus,red nucleus,substantia nigra,hippocampus and frontal cortex in phase images,.The phase values is calculated by the formula f(x)=-x·π/4096.Finally,19 MCI patients,19 AD patients,and 21 VCI patients who met the relevant diagnostic criteria and enrollment conditions were obtained.At the same time,20 healthy volunteers with normal cognitive function and age matching were collected for the same evaluation and examination.The one-factor ANOVA test was used to analyze the of the difference of phase values among the three groups of NC,MCI,and AD,and the difference between every two groups was further analyzed by the LSD method,partial correlation analysis(age-related bias was controled)was used to evaluate the correlation between the phase values of the VCI group and the HIS scores.The paired-sample T test was used to analyze the phase difference among the VCI,NC and AD groups.MCI and AD were combined into one group(MCI+AD),partial correlation analysis(age-related bias was controled)was used to evaluate the correlation between the cognitions scale scores and the phase values of the MCI+AD and VCI group,and the phase values of the brain areas with greater correlation were selected for ROC curve analysis.Results:1.There was no significant difference in the phase values of the left and right brain regions of the research subjects in every group(P>0.05).2.In the NC,MCI,and AD groups,the differences in the phase values of bilateral caudate nucleus,putamen,pallidum,red nucleus,substantia nigra,hippocampus,and frontal cortex were statistically significant(P<0.05).①MCI and NC groups had statistically significant differences in phase values in bilateral hippocampus,left caudate nucleus,and left putamen(P<0.05).②The AD and NC groups had statistically significant differences in phase values in bilateral caudate nucleus,putamen,globus pallidus,red nucleus,substantia nigra,hippocampus,and frontal cortex(P<0.05).③The AD and MCI groups had statistically significant differences in the phase values of bilateral putamen,substantia nigra and frontal cortex(P<0.05).3.The characteristic of phase values and the Correlation between phase values and HIS scores in VCI group①VCI and NC groups had statistically significant differences in the phase values of bilateral caudate nucleus,putamen,globus pallidus and frontal cortex(P<0.05).②VCI and AD groups had statistically significant differences in the phase values of bilateral globus pallidus,substantia nigra,right red nucleus,and right hippocampus(P<0.05).③In the VCI group,the phase values of the bilateral putamen and the right frontal cortex were correlated with HIS scores,and the correlation coefficients of the bilateral putamen were the highest(rright putamen=0.689,rleft putamen=0.538,P<0.05)4.Correlation between phase values and cognitions scale scores① In the MCI+AD group,the phase values of bilateral putamen,substantia nigra,hippocampus,frontal cortex,and left red nucleus are weakly correlated with the MMSE scores,and the correlation coefficients of the left putamen and right frontal cortex were the highest(rleft nucleus=0.538,rright frontal lobe=0.497,P<0.05).② In the VCI group,the phase values of bilateral frontal cortex,right caudate nucleus,and right putamen were weakly correlated with the MMSE scores(P<0.05),and the correlation coefficients of the right putamen and left frontal cortex were the highest(rright nucleus=0.465,rleft frontal lobe=0.483,P<0.05).5.Diagnostic value of phase values for cognitive impairment① The area under curve(AUC)of the left putamen and right frontal cortex in MCI+AD were 0.826 and 0.668(P<0.05),the best cut-off points were-0.061450 and-0.054294,and the sensitivities were 100%,90%,specificities were 31.6%,39.5%,accuracies were 76.41%,76.03%.②The area under curve(AUC)of the right putamen and left frontal cortex in VCI were 0.850 and 0.762(P<0.05),the best cut-off points were-0.056412,-0.049966,and the sensitivities were 90%,90%,the specificities were 76.2%,66.7%,and the accuracies were 88.15%,83.51%.Conclusion:1.Brain iron deposition in patients with AD and VCI is higher than that of healthy people of the same age,and it is related to the severity of the disease.There was a correlation between iron deposition and cerebral perfusion in the VCI group.2.Iron deposition can be used as an imaging marker of cognitive impairment,helping to screen and early detect patients with AD and VCI.With high diagnostic sensitivity and poor specificity,it can predict changes in patients’ cognitive level,but the type of cognitive impairment cannot be ensured with it alone.