Objective: This study was conducted to determine the association between lesion length measured on MRI and the severity of mechanical injury in a rat model of spinal cord trauma.
Materials and methods: Sprague-Dawley rats were subjected to a modified Allen weight drop injury and killed 4 h after injury. Their fixed, exercised cords were studied with MRI at 1.9 T.
Results: There were strong correlations between lesion length on MR images and weight drop height and square root of drop height (r2 = 0.55, p < 0.0001 and r2 = 0.63, p < 0.0001, respectively). The lesion length differences were significant versus controls for all drop heights at p values of < or = 0.002 and for the 2.5 cm animals versus the 5 and 15 cm animals (p = 0.01 and p = 0.0002, respectively), but the lengths of the 5 vs. 15 cm groups only approached significance (p = 0.06).
Conclusion: These results suggest that lesion length determined on MR images is a reliable indicator of the severity of trauma among animals subjected to weight drop injury.