Application Of Magnetic Resonance Diffusion Tensor Imaging In Evaluating The Therapeutic Effect Of Hyperbaric Oxygen Therapy In Rats With Traumatic Spinal Cord Injury

Objective: To explore the application value of diffusion tensor imaging(DTI)in dynamically evaluating therapeutic effect of hyperbaric oxygen(HBO)therapy in rats with traumatic spinal cord injury(TSCI).Materials and methods: After constructing model,sham-operated(SH)group,TSCI group and TSCI+HBO group were operated and 15 adult female Sprague-Dawley(SD)rats were operated in each group.HBO therapy was given to the rats in the TSCI+HBO group.The rats in SH group and TSCI group was under the condition of normobaric air.DTI examinations and Basso-Beattie-Bresnahan(BBB)scores were performed in three groups at 0h,6h,24 h,3d,7d,14 d,21d,28 d and 56 d post-TSCI,respectively.The outliers in the data were determined by the student residuals.Normal test was performed by Shapiro-Wilk's test.The differences of DTI characteristic parameters,including fractional anisotropy(FA),mean apparent diffusivity(MD),radial diffusivity(RD)and axial diffusivity(AD),were analyzed by two-factor repeated measures analysis of variance between TSCI+HBO group and TSCI group.LSD-t test was used to analyze the differences of the above parameters between the two groups at each time point.Pearson correlation analysis was used to analyze the correlation between DTI parameters and BBB scores in TSCI group and TSCI+HBO group.Results: The BBB scores of rats in the TSCI+HBO group were significant higher than those in the TSCI group(F=23.969,P=0.003).Except for 0h,6h and 24 h after injury,the difference between these two groups in the BBB scores at each point in time between 3d and 56 d was statistically significant(all P<0.05).FA values of rats in the TSCI+HBO group were significant higher than those in the TSCI group,while MD values and RD values were significant lower(F=745.782,P<0.001,F=114.909,P<0.001,F=408.046,P<0.001,respectively).Except for 0h and 6h after injury,the difference between these two groups in FA values,MD values and RD values at each point in time between 24 h and 56 d was statistically significant(all P<0.05).AD values of rats in the TSCI+HBO group were significant higher than those in the TSCI group(F=34.619,P=0.001).Except for 0h,6h,24 h,3d and 7d after injury,the difference between these two groups in RD values at each point in time between 14 d and 56 d was statistically significant(all P<0.05).The BBB score was correlated with FA,MD,RD and AD values,the correlation with AD values was the best(TSCI group: r=0.953,P<0.001,TSCI+HBO group: r=0.907,P<0.001).Conclusions: Hyperbaric oxygen therapy is helpful for the recovery of motor function of SCI rats.The characteristic parameters of DTI can evaluate spinal cord function and provide valuable information for the dynamic assessment of hyperbaric oxygenation in SCI rats.