Cerebral Iron Deposition And Venous Blood Oxygen Level In Patients With Alzheimer''s Disease Using Quantitative Susceptibility Mapping

PurposeThis study used quantitative susceptibility mapping(QSM)to quantitatively measure the iron deposition of the gray matter nucleus and the blood oxygen level of the cerebral vein in patients with Alzheimer's disease(AD),and the correlation between each magnetic sensitivity value(MSV)and clinical laboratory indicators and cognitive scores was analyzed.Materials and MethodsThis retrospective study was approved by the hospital ethics committee.The subjects were divided into AD group and control(CON)group.The AD group of 59cases(21 males,38 females)who meet the diagnostic criteria of the National Institute of Neurological and Communicative Diseases and the Association of Alzheimer's Disease and Related Diseases(NINCDS/ADRDA)were recruited from September 2015 to December 2018 period in Neurology of first affiliated hospital of Dalian Medical University.The CON group of 22 cases(12 males,10 females)were admitted to our hospital on voluntary or other reasons.Record clinical data and laboratory examination indexes of all the AD patients,including age,gender,course and level of education,blood pressure,total cholesterol,triglycerides,high-density lipoprotein(HDL),low density lipoprotein(LDL)and homocysteine levels,and Mini-mental State Examination(MMSE),Montreal Cognitive Assessment(MoCA),Clock Drawing Task(CDT)and Activity of Daily Living Scale(ADL)were performed by neurologists.In this study,routine MRI and enhanced gradient echo T2 star weighted angiography(ESWAN)performed by using the GE signa HDXT 3.0T MRI system with 8-channel head coil.The ESWAN raw data was saved and transmitted to a personal computer in DICOM format,and image post-processing is performed by using signal processing in nuclear magnetic resonance(SPIN)software provided by Wayne State University.Firstly,the original phase map and magnitude map of ESWAN were further processed by Susceptibility Weighted Imaging Mapping(SWIM)module in SPIN software to obtain quantitative susceptibility mapping(QSM).MSV of bilateral gray matter nuclei(head of caudate nucleus(HCN),globus pallidus(GP),putamen(PUT),thalamus(THA),red nucleus(RN),substantia nigra(SN),dentate nucleus(DN)and gyri fasciolaris(GF))and bilateral cerebral veins(internal cerebral vein(ICV),thalamus vein(TV),septal vein(SV),basal vein(BV)and dentate nucleus veins(DNV))were measured on the QSM images.The same part was repeatedly measured three times and averaged.Data analysis was performed using the statistical package for social science(SPSS)version 17.0.All the MSV were consistent with the normal distribution using the One-Sample K-S test,so the measurement data were expressed as mean±SD.All MSV and general data(age,education level,total cholesterol,triglyceride,high-density lipoprotein,low-density lipoprotein,homocysteine)of AD group and CON group were tested by nonparametric test.Pearson correlation analysis was performed on the MSV of the AD group,the MMSE score,the MoCA score and the ADL score.The Spearman correlation analysis was performed on the MSV and CDT score of the AD group.The correlation between clinical and laboratory data of the AD group and MSV were performed by Pearson correlation analysis;Spearman correlation analysis was performed between the clinical and laboratory data of the AD group and each cognitive score.The correlation analysis results are represented by heat maps.The area under ROC curve was used to evaluate the effectiveness of MSV values in diagnosing AD.P<0.05 was considered statistically significantResults1.MSV of bilateral gray matter nucleus:MSV of all brain gray matter nuclei in AD group were higher than CON group,and there were significant differences in bilateral HCN,bilateral GP,bilateral THA,right RN,right SN,right fascicular gyrus and left DN(P<0.05).2.MSV of bilateral cerebral venous:All cerebral venous MSV in AD group were higher than CON group,and there were significant differences in bilateral TV,DNV,left BV and left ICV(P<0.05).3.Correlation between MSV of bilateral gray matter nuclei and brain vein in AD group:There was a significant positive correlation between MSV of left BV and MSV of left HCN(r=0.312,P=0.016)and left RN(r=0.337,P=0.009).There was a significant positive correlation between the MSV of the right BV and the MSV of the right SN(r=0.268,P=0.040).There was a significant positive correlation between MSV of left ICV and MSV of left GP(r=0.272,P=0.037).There was a significant positive correlation between MSV value of the left TV and MSV of the right GP(r=0.263,P=0.044).There was a significant positive correlation between the MSV of the right SV and the MSV of the right GF(r=0.276,P=0.035).4.The correlation between the MSV of bilateral gray matter nuclei and each cognitive score in AD group:The MSV of bilateral HCN(r_L=-0.488,P=0.000;rR=-0.436,P=0.001),bilateral PUT(r_L=-0.290,P=0.027;r_R=-0.347,P=0.008),and right GF(r=-0.275,P=0.037)had a significant negative correlation with the MMSE score;There was a significant negative correlation between the MSV of bilateral HCN(r_L=-0.388,P=0.003;r_R=-0.438,P=0.001),bilateral PUT(r _L=-0.317,P=0.015;r_R=-0.348,P=0.007)and MoCA scores;The MSV of bilateral HCN(r_L=-0.366,P=0.007;r_R=-0.538,P=0.000),bilateral PUT(r_L=-0.343,P=0.011;r _R=-0.366,P=0.007),bilateral GF(r_L=-0.295,P=0.030;r_R=-0.311,P=0.022)had a significant negative correlation with CDT scores;There was no significant correlation between the MSV of the bilateral gray matter nuclei and ADL scores(P>0.05).5.The correlation between the MSV of bilateral cerebral venous and the cognitive scores in AD group:The MSV of bilateral TV(r _L=-0.524,P=0.000;r_R=-0.460,P=0.002),bilateral ICV(r_L=-0.387,P=0.003;r_R=-0.313,P=0.017),bilateral DNV(r _L=-0.450,P=0.000;r_R=-0.454,P=0.000)had a significant negative correlation with MMSE score;The MSV of bilateral TV(r_L=-0.455,P=0.000;r_R=-0.380,P=0.003),bilateral DNV(r_L=-0.517,P=0.000;r_R=-0.464,P=0.000)has significant negative correlation between MoCA scores;There was a significant negative correlation between the MSV of bilateral TV(r_L=-0.526,P=0.000;r_R=-0.505,P=0.000),bilateral DNV(r_L=-0.398,P=0.002;r_R=-0.281,P=0.031),the right SV(r=-0.343,P=0.008)and the CDT score;The MSV of bilateral TV(r_L=-0.588,P=0.000;r_R=-0.491,P=0.000),bilateral SV(r _L=-0.373,P=0.005;r_R=-0.319,P=0.018),the left BV(r=-0.287,P=0.034)has significant negative correlation between ADL score.6.Correlation analysis between MSV value of gray matter nucleus and cerebral vein and clinical and laboratory data in AD group:The MSV of right GP(r=0.302,P=0.049),left DNV(r=0.375,P=0.013)value is positively correlated with the course of the disease;The MSV of the right SV(r=0.285,P=0.030)was positively correlated with total cholesterol.The MSV of THA(r_L=-0.347,P=0.0088;r_R=-0.280,P=0.033)were inversely related to triglyceride content;The MSV of the right DNV(r=0.262,P=0.047)was positively correlated with triglyceride content;The MSV value of the left internal cerebral vein(r=-0.266,P=0.046)was inversely correlated with HDL content;The MSV of gray matter nucleus and cerebral vein were not correlated with LDL and homocysteine content(P>0.05).7.The effect of the MSV of bilateral gray matter nucleus and bilateral cerebral venous on the diagnosis of AD:ROC analysis showed that MSV of the left GP had the largest AUC of 0.685,with a threshold of 139.29,the sensitivity was 62.7%and the specificity was 72.7%.Among the bilateral cerebral veins,the MSV value of the left DNV had the largest AUC(0.685)with the threshold of 177.5,the sensitivity was 37.3%,and the specificity was 95.5%.Conclusion1.MSV of the gray matter nucleus of AD patients increased,and abnormal iron deposition was found,which was associated with cognitive function;The MSV of gray matter nucleus can be used for the differential diagnosis of AD,especially the left GP.2.Increased MSV value of cerebral veins and decreased blood oxygen saturation in AD patients also affect cognitive scores;MSV value of cerebral vein can be used for the differential diagnosis of AD,especially for the left dentate nucleus vein.3.Iron deposition in the gray matter nucleus of patients with AD is associated with decreased local oxygen saturation.