Correlation of MR Diffusion Tensor Imaging Parameters with ASIA Motor Scores in Hemorrhagic and Nonhemorrhagic Acute Spinal Cord Injury

This study investigated correlations between American Spinal Injury Association (ASIA) clinical injury motor scores in patients with traumatic cervical cord injury and magnetic resonance (MR) diffusion tensor imaging (DTI) parameters. Conventional imaging and DTI were performed to evaluate 25 patients (age, 39.7 +/- 13.9 years; 4 women, 21 men) with blunt spinal cord injury and 11 volunteers (age, 31.5 +/- 10.7 years; 3 women, 8 men). Cord contusions were hemorrhagic (HC) in 13 and non-hemorrhagic (NHC) in 12 patients. The spinal cord was divided into three regions to account for spatial and pathological variation in DTI parameters. Comparisons of regional and injury site mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity (lambda(perpendicular to)), and longitudinal diffusivity (lambda(parallel to)) were made with control subjects. ASIA motor scores were correlated with DTI using linear regression analysis. HC and NHC patients showed significant reduction (p < 0.001) in MD and lambda(parallel to) in all three regions. At the injury site, significant decreases in FA and lambda(parallel to) were seen for both injury groups (p < 0.001). lambda(perpendicular to) values were significantly increased only for patients with NHC (p < 0.05). Significant reduction in FA and lambda(perpendicular to) (p < 0.0001) was observed at the whole cord level between the injured (NH and NHC) and control groups. Within the NHC group, strong correlations were observed between ASIA motor scores and average MD, FA, lambda(perpendicular to), and lambda(parallel to) at the injury site. However, no correlation was observed within the HC group between any of the DTI parameters and ASIA motor scores. DTI parameters reflect the severity of spinal cord injury and correlate well with ASIA motor scores in patients with NHC.