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Small world properties changes in mild traumatic brain injury
Author(s) -
Zhou Yongxia
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25548
Subject(s) - betweenness centrality , diffusion mri , clustering coefficient , resting state fmri , traumatic brain injury , medicine , effective diffusion coefficient , magnetic resonance imaging , cluster analysis , centrality , radiology , psychiatry , artificial intelligence , mathematics , computer science , combinatorics
Purpose To investigate local and global efficiency changes characterized by small‐world properties based on resting‐state functional MRI, such as centrality and clustering coefficient, in mild traumatic brain injury (MTBI) patients; and to associate these findings with axonal injury as measured by diffusion tensor imaging (DTI) as well as with post‐concussive symptom (PCS). Materials and Methods Thirty patients (mean age 35 ± 13 years) with clinically defined MTBI and 45 age‐matched healthy controls (mean age 37 ± 10 years) participated in the experiments. Resting‐state functional MRI was performed using gradient echo planar imaging sequence with 3 Tesla MRI scanner to obtain functional small‐world networks. Out of all participants, 20 MTBI patients and 20 controls had available DTI data with three b‐values (0, 500, 1000) s/mm 2 and 30 directions for diffuse axonal injury analyses. Results Compared with controls, MTBI patients showed lower relative betweenness centrality ( P = 0.01), but significantly higher clustering coefficient ( P = 0.04), and these two metrics correlated negatively in patients (r = ‐0.77; P < 0.001). Regions with lower betweenness centrality (e.g., frontal and occipital) corresponded with the regions of reduced FA in patients, while global FA reduction correlated with betweenness centrality (r = 0.48; P = 0.03) and clustering coefficient (r = ‐0.46; P = 0.04) in MTBI patients. In addition, there was significantly higher thalamocortical connectivity that correlated with clustering coefficient (r = 0.39; P = 0.03) in patients. Also, patients with higher clustering coefficient tended to have less PCS score with negative correlation (r = ‐0.4; P = 0.04). Conclusion Our results demonstrated significant functional small‐world properties changes in patients with MTBI, and suggest decreased global efficiency, possibly due to diffuse axonal injury and local network upregulation including increased thalamo‐cortical connectivity. Level of Evidence : 2 Technical Efficacy : Stage 2 J. MAGN. RESON. IMAGING 2017;46:518–527