The Analysis Of Structural Brain Network Based On DTI In PD Patients With Depression

Purpose:Depression is common in Parkinson's disease?PD?and is correlated with the severity of motor deficits and quality of life.The present study aimed to investigate alterations in the structural brain network related to depression in Parkinson's disease?d-PD?and their correlations with structural impairments of white matter?WM?.Methods:Data were acquired from the Parkinson Progression Markers Initiative?PPMI?database.A total of 84 de novo and drug-na?ve PD patients were screened and classified into two groups according to the 15-item Geriatric Depression Scale?GDS-15?:d-PD?n=28?and non-depression in PD?nd-PD,n=56?.Additionally,37healthy controls?HC?were screened.All subjects underwent DTI and 3D-T₁WI on a 3.0T MR scanner.Part ?:Individual fiber number?FN?weighted structural brain networks were constructed and analyses were performed using graph theory and network-based statistics?NBS?at both global and local levels.Differences in global topological properties were explored among the three groups.The association models between node and edge changes and the GDS-15 were constructed to detect regions that were specifically correlated with d-PD.Tract-based spatial statistics?TBSS?was used to detect structural impairments of WM between the d-PD and nd-PD groups.The correlations between altered global topological properties and structural impairments were analyzed in the d-PD group.Part?:Individual fractional anisotropy?FA?weighted structural brain networks were constructed analyses were performed using graph theory at both global and local levels.Differences of topological properties between d-PD and nd-PD patients and their correlation with GDS-15 scores were explored.Results:Part?:The global efficiency and characteristic path length of FN weighted structural brain network were impaired in the d-PD group compared with those in the nd-PD and HC groups.Thirteen nodes and 1 subnetwork with 10 nodes and12 edges specifically correlated with d-PD were detected.The left hippocampus,left parahippocampal,left lingual,left middle occipital,left inferior occipital,left fusiform,left middle temporal,and left inferior temporal regions were all involved in the results of node and edge analysis.No WM microstructural impairments were identified in the d-PD group.Part?:The global topological properties of FA weighted structural brain network,including global efficiency,local efficiency and characteristic path length,were altered in the d-PD group compared with the nd-PD group,and correlated with GDS-15 scores.The small-worldness was altered in d-PD group,but did not correlate with GDS-15scores.The brain regions in prefrontal,precuneus,hippocampus,basal ganglia and cerebellum showed decreased degree in d-PD patients compared to nd-PD patients,and their degree were correlated with GDS-15 scores,except for the right middle frontal gyrus?orbital part?and thalamus.Conclusion:Our study suggests that the structural brain network in the d-PD group shows disordered organization compared with that in the nd-PD group and that these abnormalities correlate with GDS-15 scores.