| Purpose:Mild traumatic brain injury (mTBI) can cause varying levels of cognitive impairments,which are probability associated with the subtle microstructural damage of white matter tracts.The purpose of the present study was to verify the integrity changes of brain white matter in mTBI patients,and to evaluate the relationship between the alteration of the white matter integrity and the level of cognitive function.Materials and methods:Forty-one subjects diagnosed with mild TBI(28men,13women), from 19 to 42 years,mean (SD) 30.3171(6.63) years,education years range 4-19 years, mean(SD) 13.1463(3.32) years, whose Glasgow Coma Scale (GCS) scores are 13-15,mean(SD) 14.7317(0.63),comlpeted the study and were matched according to age, sex to a group of 37 healthy controls(table2). Diffusion-tensor imaging was performed in mTBI patients within 7 days of injury and all volunteers in All MR images were acquired with a Philips Achieva 3.0T TX MRI scanner (Royal Philips, Amsterdam, Netherlands).Brain regions characterizing mTBI were detected by AAL (Automated Anatomical Labeling) software package and JHU DTI-based white-matter atlases and FA/MD values were obtained respectively.AII subjects accepted cognitive function assessment using NIH Toolbox online tools.Two sample T test of inter-groups FA/MD(mean diffusivity/fractional anisotropy)values were conducted,and also the cognitive assessment scores were analyzed by covariance analysis.Last but not least,the correlation between regions exhibiting significant differences in structural integrity and the cognitive scores were analyzed in acute mTBI patients.Results:The DTI data based on Automated Anatomical Labeling(AAL) shows significantly reduced MD in right insula(t=2.370, p=0.020), supramarginal gyrus (SG) (t=1.788, p=0.078), angular gyrus (AG) (t=1.729, p=0.088) and left amygdala (t=1.747, p=0.085) as well as ruduced FA value in left superior frontal gyrus (t=1.714, p=0.091), insula (t=1.779, p=0.079) and right posterior cingulate gyrus (PCG) (t=1.973, p=0.052), precuneus(t=1.926,p=0.058),putamen(t=2.402/p=0.019),pallidum(t=1.69 7,p=0.094) among patients in mTBI group. The analysis result based on JHU white-matter tractography atlas shows reduced MD in right cingulum (t=1.997,p=0.049) in mTBI but there is no difference in FA between two groups.In addition,the third result based on ICBM-DTI-81 white-matter labels atlas suggests reduced MD in right inferior cerebellar peduncle(t=1.674,p=0.098),cerebral peduncle(t=1.915, p=0.059) and left medial lemniscus(t=2.405, p=0.019),retrolenticular part of internal capsule(t=2.015, p=0.047),cingulum(t=1.925, p=0.058) as well as reduced FA in right superior cerebellar peduncle(t=-1.87, p=0.065) in mTBI patients.Inter-group covariance analysis were uesd to assess the cognitive function of the mTBI patients,and, the result shows that the mTBI group had significantly lower scores on AVL(Auditory Verbal Learning Test, F=2.788, p=0.099)、PSM (Picture Sequence Memory, F=4.572, p=0.036)、FIC (Flanker Inhibitory Control and Attention, F=2.881, p=0.094)、OSD (Oral Symbol Digit, F=11.659, p=0.001) scales compared with the normal controls. Auditory memory function was positive correlated with MD value in right supramarginal gyrus,angular gyrus as well as FA value in left superior frontal gyrus and right precuneus. Visual memory function demonstrated a positive correlation with the MD value in right angular gyrus.The excutive function, attention function and processing speed positively correlate with MD in right supramarginal gyrus and angular gyrus.Additionally,processing speed also positively correlates with MD in left superior frontal gyrus,insula and FA in right precuneus.Conclusion:Reduced structural integrity in many brain regions and neurocognitive deficiency may exsit at the acute phase of mTBI, the subtle changes in these regions corralte with patients’cognitive function.Combine DTI and neurocognitive messures promote the understanding about the potential mechanism of nerve pathophysiology and psychology. |
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