| Objective: To explore possible mechanism of the clinical symptoms in patients with brain concussion(BC) by analyzing the amplitude of brain neurons’ spontaneous activity, the cooperativity between brain areas and brain network spatial topological properties with the use of amplitude of low-frequency fluctuation(ALFF), based-seed resting-state functional connectivity(RSFC) and complex networks analysis based on the graph theory, and to improve the understanding of the central pathophysiological mechanisms in concussion patients negative on conventional imaging examinations.Methods: Collected 162 cases of patients with traumatic brain injury from April2013 to February 2015 and chose 18 patients whose onventional CT, routine MRI and SWI were negative but clinically diagnosed as concussion. and 18 healthy volunteers with sex, age and education level matched as healthy controls(HCs) group. Two groups were performed with resting state functional magnetic resonance imaging scans within 7 days after injury. Data analysis include:(1) After isolating bold data by using Onis2.5 software, data preprocessing, the calculation of ALFF and the analysis of two sample t-test bewteen two groups were performed by DPARSFA software(P <0.01).(2) Selecting ALFF different brain area as the regions of interest(ROIs), then they were proceed the whole functional connectivity based on the seed point correlation analysis and analysed by using two sample t-test bewteen two groups(P <0.01).(3) using Gretna and Brain Net Viewer software, automated anatomic markers(AAL) template was defined and extracted, then a quadratic matrix and binary functional connective network were built, and every parameters under different network sparse degree index were calculated and used to two sample t-test bewteen two groups(P < 0.05). All subjects underwent clinical rating scale(GCS, RPSQ). The general condition and the clinical score between BC group and HCs group were analyzed with IBM SPSS 19.0 software for two-sample t test. Clinical rating scale and ALFF abnormal area in BC group were proceeded for Pearson correlation analysis respectively(P < 0.01).Results :(1) GCS score(t =-1.458, P =0.163) in BC group was similar to HCs,ROSQ score higher than HCs(t = 13.617, P = 0.001).(2) Traditional imaging examinations including CT and MRI T1 WI, T2 WI, T2-FLAIR and SWI images of alll the subjects were negative.(3) Compared with HCs, ALFF increased areas in patients included bilateral brain cortex around calcarine fissure(AAL44 on the right side and AAL43 on the left side), the left middle temporal gyrus(AAL85);ALFF decreased areas included the right cerebellum posterior lobe(AAL92, 94), the right posterior cingulate cortex(AAL36) and the left precuneus(AAL67)(P < 0.01, by Alpha Sim, clusters > 40).(4) Compared with HCs, the right posterior cingulate cortex as ROI showed increased functional connectivity with left superior frontal gyrus(AAL23) and triangular part of the left inferior frontal gyrus(AAL13), decreased functional connectivity with right parahippocampal gyrus(AAL40); the left precuneus as ROI showed increased functional connectivity with right postcentral gyrus(AAL 58) and left middle occipital gyrus(AAL51), decreased functional connectivity with left parahippocampal gyrus(AAL39), bilateral middle temporal gyrus(AAL 85,86), left superior medial frontal gyrus(AAL23) and right middle frontal gyrus(AAL8); the right cerebellum posterior lobe as ROI showed increased functional connectivity with right cerebellum anterior lobe(AAL98), right precuneus(AAL68) and decreased functional connectivity with left medial superior frontal gyrus(AAL23); the right calcarine fissure as ROI showed increased functional connectivity with left postcentral gyrus(AAL57), right medial superior frontal gyrus(AAL24) and decreased functional connectivity with right brainstem, left pallidum(AAL75); the left calcarine fissure as ROI showed increased functional connectivity with bilateral precuneus(AAL67,68), left inferior parietal(AAL61) and decreased functional connectivity with left hippocampus(AAL37); and the left middle temporal gyrus asROI showed increased functional connectivity with left inferior temporal gyrus(AAL89) and decreased functional connectivity with right cerebellum anterior lobe(AAL 98), right middle frontal gyrus(AAL8).(P < 0.01, by Alpha Sim, clusters > 40).(5) Compared with HCs, normalized clustering coefficient(γ) showed to be moderately elevated, normalized characteristic path length(λ) slightly reduced and small-wordness(σ) mild increased. Changes of local efficiency(Elocal) and global efficiency(Elocal) were not obvious. Based on Dmin=0.13, patients’ betweeness decreased in right superior medial orbital frontal gyrus(AAL26), right pallidum(AAL76) and bilateral heschl gyrus(AAL79,80) and increased in left inferior parietal gyrus(AAL61) and left middle occipital gyrus(AAL51), regional normalized clustering coefficient increased in right superior medial orbital frontal gyrus(AAL26)and left posterior cingulate gyrus(AAL35) and decreased in triangular part of the right inferior frontal gyrus(AAL14) and left inferior parietal gyrus(AAL61), and nodal mean local efficiency increased in right superior medial orbital frontal gyrus(AAL26), left posterior cingulate gyrus(AAL35) and bilateral supplementary motor gyrus(AAL19、20) and decreased in triangular part of the bilateral inferior frontal gyrus(AAL13,14) and opercular part of the left inferior frontal gyrus(AAL11)(P﹤0.05).(6) BC patients’ ALFF abnormal areas were not significant correlated with age,level of education, the course of the disease, GCS and RPSQ scores.Conclusions:(1) There were abnormalities of the strength and connection mode brain neurons’ spontaneous activity in rest-state brain functional network in concussion, especially the changes of default mode network.(2) BC patients presented abnormalities in whole and local properties as well as nodal mean local efficiency of resting state functional topology network with overall the trend of randomization and involving functional abnormal generalization..(3) The change of default mode network and emotional loop in BC patients was particularly significant, thereby affecting patients with normal cognitive function,which may be one of the main mechanisms of cognitive dysfunction and mood changes in BC patients. |
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