MRI CHARACTERIZATION OF DIFFUSION-COEFFICIENTS IN A RAT SPINAL-CORD INJURY MODEL

Apparent diffusion coefficients (ADC) were measured in a rat spinal co rd weight-drop injury model. After sacrifice, the spinal cords were fi xed in situ and excised for MR imaging and ADC measurement. Diffusion is anisotropic in normal gray and white matter. There were significant decreases in ADCs measured along the longitudinal axis of the injured cord and increases in ADCs measured transverse to the cord. Injured s egments demonstrated reductions in diffusion anisotropy in the white m atter. Diffusion was completely isotropic at the epicenter of the weig ht drop injury. Significant decreases in longitudinal ADC and increase s in transverse ADC were observed in portions of the cord which appear ed normal on conventional spin-echo and calculated T-2 images. Thus AD C measurement may complement routine imaging for evaluation of spinal cord injury.