Diffusion tensor imaging in the evaluation of the long-term efficacy of HBO2 therapy in rats after traumatic spinal cord injury

Objective: This study explored the feasibility of diffusion tensor imaging (DTI) in the evaluation of the long-term efficacy of hyperbaric oxygen (HBO2) therapy in rats after traumatic spinal cord injury (TSCI) with different degrees of injury. Method: Adult Sprague-Dawley rats (total n = 60) were randomly separated into three groups of mild, moderate and severe TSCI (20 rats per group). Each group was then randomly divided into TSCI and TSCI+HBO2 subgroups (10 rats per subgroup). Basso Beattie and Bresnahan (BBB) scores and DTI parameters including fractional anisotropy (FA), mean apparent diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AD) were collected at pre-TSCI and at 0, six and 24 hours, and three, seven, 14, 21, 28 and 56 days post-TSCI. Two-way repeated measures analysis of variance was used for comparison between the TSCI and TSCI+HBO2 subgroups over time in the mild, moderate and severe TSCI groups. Pearson correlation analysis was applied to analyze the correlations between BBB scores and DTI parameters. Results: BBB scores, FA, MD and RD values showed significant differences between the TSCI and TSCI+HBO2 subgroups over time in the mild, moderate and severe TSCI groups (all p<0.01). FA, MD and RD values were positively correlated with BBB scores in all TSCI and TSCI+HBO2 subgroups (all p<0.05). Conclusions: DTI parameters, especially MD, could quantifiably assess the long-term efficacy of HBO2 therapy and reflect the functional recovery in rats after TSCI with different degrees of injury.