The Study Of Whole Brain Amide Proton And Microstructural Changes And Correlation With Cognitive Decline In Drug-Naive Patients With Major Depressive Disorder

Part Ⅰ Changes in Whole Brain APTw Values and Correlation with Cognitive Decline in Drug-Naive Patients with Major Depressive Disorder:A Preliminary APT MRI StudyObjective:Amide proton transfer(APT)imaging has been widely used in a variety of central nervous system diseases such as brain tumors,stroke,and neurodegeneration,but it has rarely been used to evaluate psychiatric disorders.The value of APT MRI in major depressive disorder(MDD)is unclear.The purpose of this study was to try to apply APT imaging and investigate its correlation with cognitive decline in MDD patients.Methods:This study included 17 drug-naive MDD patients(mean age=26.41±4.84)and 17 healthy controls(mean age=24.65±2.00).The cognitive domains assessment had execution,working memory,language learning,and semantic long-term memory functions.The diagnostic value of APTw for MDD was analyzed using the ROC curve.Correlation analysis was performed to determine the relationship between changes in mood and cognitive function and APTw values in various brain regions.Results:Patients with MDD have impaired executive function,verbal learning and memory,and long-term semantic memory.The APTw values of the orbitofrontal,rostral anterior cingulate,fusiform,basal forebrain and amygdala in MDD patients were statistically different from normal controls(P<0.05).The APTw values of the orbitofrontal,rostral anterior cingulate,and fusiform had good diagnostic value(all AUC values were greater than 0.7).The APTw values in the orbitofrontal,rostral anterior cingulate,and basal forebrain had mild to moderate correlations with the cognitive domain scale.Conclusions:Increased APTw values in the right rostral anterior cingulate in MDD patients may be a neuroimaging biomarker for the diagnosis of MDD;Changes in APTw values in the frontal-limbic system,basal forebrain,and fusiform are closely associated with cognitive function in patients.Our study suggests that APT MRI has value as a sensitive imaging method to be further replicated in future studies.Part Ⅱ Changes in Whole Brain Microstructure and Correlation with Cognitive Decline in Drug-Naive Patients with Major Depressive Disorder:An MRI Study Based on NODDI ModelObjective:Diffusion MRI imaging reveals white matter impairment in the brain of MDD,but conventional diffusion imaging has low specificity and lacks assessment of cortical and gray matter regions.Neurite orientation dispersion and density imaging(NODDI),an advanced diffusion sequence,has been less frequently reported in MDD.This study aimed to assess the microstructural changes in the brains of MDD patients at two levels:white matter and cortex and subcortical gray matter nuclei and to discover the characteristic patterns of brain microstructural damage.Methods:Seventeen patients with Drug-Naive MDD and 17 healthy volunteers were included through recruitment.Enrolled subjects were refined with demographic data and NODDI imaging data,which were post-processed to obtain whole-brain microstructural parameters(Neurite density index(NDI),Orientation dispersion index(ODI),Isotropic volume fraction(fiso)).The neuropsychological scales provided an evaluation of the subject’s emotional and cognitive functions.The diagnostic efficacy of microstructural parameters in different brain regions was obtained by subject work characteristic curveanalysis,and its correlation with changes in mood and cognitive function was analyzed by correlation.Results:Microstructural damage in MDD exists in both white matter fiber tracts and cortical and subcortical gray matter nuclei.White matter microstructural changes mainly affected joint fibers(corpus callosum),contact fibers(superior longitudinal fasciculus,superior fronto-occipital fasciculus,inferior fronto-occipital fasciculus,cingulum,sagittal stratum),projection fibers(corticospinal tract,corona radiata,posterior thalamic radiation),intra-brainstem fiber tracts,and specific fibers within the brain,while cortical and subcortical gray matter nuclei were mainly affected some nodes of the frontal-limbic network,default network,and emergent network.The NDI,fiso,and ODI values of some white matter fiber tracts and cortical and subcortical nuclei were associated with memory,executive,and language functions.Conclusions:NODDI is a tool to comprehensively assess microstructural changes in the brain of MDD patients that occur extensively in gray and white matter regions of the brain.Multiple white matter fiber tracts and multi-node,multi-network abnormalities in the frontal-limbic,default,and emergent networks may characterize the microstructural damage model of MDD.