The Study Of Brain Functional Magnetic Resonance Imaging On Post-stroke Depression

PartⅠThe study the characteristics of brain morphology of patientswith post-stroke depressionObjective To investigate the volume change of the amygdala and hippocampus inpatients with post-stroke depression(PSD) and analyze the relationship of PSD and anatomyposition of infarct lesion using MR imaging.Methods Quantitative MRI about volumes of the amygdala and hippocampus wasstudied in 11 patients with post-stroke depression and compared with 13 stroke patientswithout depression(CONT) and 15 age-matched controls(NORM).Results 1.PSD group and NORM group exhisited similar significant hippocampusand amygdala asymmetry(left smaller than right).2.The volume of the bilateralhippocampus and amygdala in PSD group was significantly smaller than that in CONTgroup (P＜0.05).The volume of right hippocampus in PSD group was smaller than that inNORM group(P=0.034);3.There was no correlation between the hippocampus andamygdala volume abnormalities and the score of HAMD in PSD patients (P＞0.05);4.Thedifferences of Laterality Index(LI) of amygdala volume among PSD group,CONT groupand NORM group were statistically difference (p = 0.04),especially in PSD-CONT group.;5.PSD group and NORM group has a significant statistical difference when infarct lesionswere located in frontal-temporal-parietal cortex and the brain stem and cerebellum.The shortest distance between prefrontal cortex and lesions in PSD group is shorter than thatin CONT group,but no significant statistical difference;6.The size of the correlationcoefficient between all targets and PSD are the brain stem and cerebellum＞the size of leftamygdala＞the size of right amygdala＞frontal-temporal-parietal cortex＞the size of lefthippocampus＞the size of right hippocampus＞occipital cortex＞distance between leftprefrontal cortex and lesion＞posterior cerebral＞distance between right prefrontal cortexand lesion＞left frontal lobe＞basal ganglia area＞hippocampus and amygdale area＞anterior cerebral＞corona radiata district＞right frontal lobe;7.A good discriminantequation was established.Conclusion Cerebral infarction in brainstem,cerebellum,frontal- temporal-parietalcortex and the volume of amygdale and hippocampus shows well correlation with the PSD,These findings support the hypothesis that the hippocampus and amygdalawithin limbic system-cortical networks may play a crucial role in the pathogenesis ofpost-stroke depression.PartⅡThe study of brain functional magnetic resonance imaging onpost-stroke depressionObjective To explore the characteristics of brain activity in patients with post-strokedepression (PSD) by probing the differences of neural activation associated with reactivityto different affective stimuli pictures using functional MR imaging (fMRI).Methods Neural responses to neutral,positive,negative emotional pictures (fromInternational Affective Pictures System,IAPS) stimuli based on block-design weremeasured by functional magnetic resonance imaging(fMRI) in 11 patients with post-strokedepression PSD,13 stroke patients without depression(CONT) and 15 age-matched healthy controls(NORM).the fMRI data were analyzed by using Analysis of FunctionalNeuroimages (AFNI) software.Results 1.Observing the neutral,positive,negative emotional pictures,All patientsin PSD group,CONT group and NORM group showed mainly activated areas using fMRIinclude the prefrontal cortex - subcortical reticular system,basal ganglia (thalamus,globuspallidus,caudate nucleus) and limbic system (hippocampus,parahippocampal gyrus,amygdale),insula,temporal lobe,occipital lobe,brain stem and cerebellum.2.PSDgroup Comparison:Positive - neutral showed mainly activated areas include bilateralsuper-,mid- and infer- frontal gyrus,precentral gyrus,superior parietal lobule,precuneus,angular gyrus,splenium cingulate gyrus,insula,thalamus,lentiform nucleus,hippocampus,parahippocampal gyrus,super-,mid- temporal gyrus,occipital visual cortex,pons,midbrain,cerebellar hemispheres,right amygdala.(negative) and bilateral occipitallobe(positive);Negative-neutral showed mainly activated areas include bilateral super-,mid- frontal gyrus,precentral gyrus,superior parietal lobule,precuneus,angular gyrus,,supramarginal gyrus,cingulate gyrus,corpus callosum,insula,thalamus,caudate nucleus,lentiform nucleus,hippocampus,parahippocampal gyrus,occipital visual cortex,pons,midbrain,cerebellar hemisphere.(negative) and left amygdala,dorsal thalamus and insula,bilateral occipital lobe(positive);Negative-positive showed mainly activated areas includebilateral super-,mid- frontal gyrus,lentiform nucleus,corpus caliosum,anterior cingulategyrus,left insula,right caudate nucleus(negative) and bilateral super-,mid- frontal gyrus,precentral gyrus,precuneus,splenium cingulate gyrus,insula,thalamus,caudate nucleus,lentiform nucleus,amygdala,occipital visual cortex and cerebellum(positive).3.PSD-NORM group inter-group comparison:Identify neutral picture showed mainly activatedareas include bilateral superior parietal lobule,cingulate gyrus,corpus callosum,leftmid-frontel gyrus,right parahippo- campal gyrus,hippocampus,thalamus,rightsupramarginal gyrus(negative) and right cuneus,occipital visual cortex,left cerebellarhemisphere(positive).;Identify positive picture showed mainly activated areas include bilateral parahippocampal gyrus,hippocampus,dorsal thalamus,superior parietal lobule,precuneus,,mid-infer-temporal gyrus,midbrain,cerebellar hemisphere,right mid-infer-frontel gyrus,,lentiform nucleus,insular(negative) and bilateral cerebellar hemisphere,occipital visual cortex and right parietal lobe(positive).;Identify negative picture showedmainly activated areas include bilateral parahippocampal gyrus,thalamus,cuneus,occipitalvisual cortex and cerebellar hemisphere,right hippocampus,amygdala,temporal,parietallobe(positive) and left mid-infer- frontal gyrus,superior parietal lobule,right inferiorparietal lobule.(negative).4.PSD-CONT group inter-group comparison:Identify neutralpicture showed mainly activated areas include bilateral super-mid- temporal gyrus,occipital visual cortex,left mid-infer- frontal gyrus,lentiform nucleus,insula,righthippocampaus,parahippocampal gyrus,superior parietal lobule(positive) and leftsuper-mid- frontal gyrus,(negative);Identify positive picture showed mainly activatedareas include bilateral parahippocampal gyrus(right obviously),inferior frontal gyrus,cuneus,super-mid-infer- temporal gyrus,fusiform gyrus,splenium cingulate gyrus,occipital visual cortex,right superior parietal iobule,(positive) and left mid-infer- frontelgyrus(negative);Identify negative picture showed mainly activated areas include righthippocampus,parahippocampal gyrus,superior parietal lobule,left mid-infer- temporalgyrus (negative) and occipital visual cortex (positive).Conclusion Patients with PSD presented an close relationship with limbic system(hippocampus,parahippocampal gyrus,amygdala),middle frontal gyrus,superiorparietal lobule,cingulate gyrus,the right dorsal thalamus,insula,the brain stem andcerebellar hemisphere,which may be involved in the mechanism of pathophysiology inPSD by demaging the structure and function of multiple neural loops,primarily in thelimbic system - cortex - the striatum - the globus pallidus - thalamus neural loop. PartⅢThe research of the integrity of brain white matter in post-stroke depression(PSD) Diffusion tensor imaging (DTI) and its methodsSection 1 The study of magnetic resonance diffusion tensor imaging(DTI) on post-stroke depression(PSD)Objective To investigate the FA value changes in brain white matter of patients withpost-stroke depression (PSD) using magnetic resonance diffusion tensor imaging (DTI).Methods Diffusion tensor MR imaging were performed in 11 patients withpost-stroke depression (PSD),13 stroke patients without depression(CONT) and 15age-matched healthy controls(NORM).The appearances of DTI in patients with PSD wereanalyzed by comparing the FA values of brain white matter and brain activation areasamong three groups based on regions of interest (ROI) methods and voxel-based measuremethods (VBM).Results 1.The areas of FA values having statistically significant differences (P＜0.05)included both parts of the frontal lobe,parietal lobe,left internal capsule,right occipitallobe in PSD-NORM group,left frontal lobe,left parietal lobe,left internal capsule,theanterior part of cingulate gyrus in PSD-CONT group and only right thalamus inCONT-NORM group.2.The areas of the Laterality Index (LI) of FA values havingstatistically significant differences (P＜0.05) included parietal lobe and internal capsule inPSD-CONT Group and PSD-NORM group (parietal Pp-c = 0.006,Pp-n = 0.032;internalcapsule forelimb Pp-c = 0.014,Pp-n = 0.001).The remaining parts of unilateral index (LI)showed no statistical difference.3.The activated cerebral regions having statisticallysignificant differences included both parts of superior-middle frontal gyrus,parietal lobe,cingulate gyrus,corpus callosum,insula,thalamus,lenticularnucleus,temporal lobe,occipital lobe and cerebellum in PSD-NORM group,bilateral inner parts of frontal lobeand parietal lobe,the body of cingulate gyrus,right temporal lobe,left occipital lobe inPSD-CONT group and a little white matter around lateral cerebral ventricle (frontal lobe, parietal lobe),insula,anterior corpus callosum,temporal lobe in CONT-NORM group.4.The images of nonlinear normalization were more accurate and better than that of linearnormalization.Conclusion Compared with patients in CONT group and NORM group,Patients withPSD presented an close relationship with the left frontal lobe,parietal lobe,left internalcapsule,cingulate gyms,corpus callosum and bilateral inner parts of frontal lobe andparietal lobe.DTI provides a good platform that can more accurately evaluate themicrostructural changes of brain white matter in vivo,which is expected to offer a newmethod and idea for prediction,treatment and assessment of clinical efficacy in patientswith PSD.Section 2 The study of methods of magnetic resonance diffusion tensorimaging (DTI)—White matter fiber tracking method for the study ofaging:ninety cases of quantitative diffusion tensor imaging (DTI) analysisObjective To investigate the difference and significance of Fractional anisotropy (FA)of precentral portion of the pyramidal tract (PRPT,ie from cerebral peduncle to precentralgyrus) in different age-groups health volunteers using quantitative diffusion tensorimaging (DTI) based on fiber tractography.Methods Quantitative DTI based on fiber tractography were performed in 90 healthvolunteers (20-83years) divided into 6 age groups at a 1.5T MR scanner.Standardizedimages data were analyzed for the relationship between FA values of PRPT and aging.Results The FA value of bilateral PRPT in each age group distribute similarly,inwhich FA value of corona radiata is the lowest and the posterior limb of the internal capsuleis the highest;The FA values of sections is declining with aging,showed the fibers of these parts had significantly aging and the most obvious aging part is the frontal lobe;we foundthe procedure of aging in the frontal lobe and cerebral peduncle does exist mutationperiod(P＜0.0001,P=0.0068).Conclusion Diffusion tensor imaging (DTI) is a sensitive method for detecting themicrostructural changes and aging process of brain white matter;Whether the Mutation ofaging in the frontal lobe and cerebral peduncle is the physical signs of aging,it should befurther examined.