In vivo imaging of blood-spinal cord barrier permeability with dynamic contrast enhanced MRI of spinal cord injury

Serial in vivo dynamic contrast enhanced MRI studies were performed on spinal cord injured rats on post-injury days 0, 10, 20 and 30 to determine the distribution of gadopentetate-dimeglumine (Gd) concentration in injured cord tissue. A two-compartment pharmacokinetic model was fitted to describe the time course of the concentration data at the epicenter of injury for each post-injury day. From these fits, the rates of Gd transport between plasma and injured cord tissue were determined to estimate the blood-spinal cord barrier permeability. The results indicated a steady decrease in the Gd transport rates with a concomitant improvement in rat's motor functions with post-injury time. Specifically, the rates of Gd accumulation in injured cord and its clearance correlated with the neurobehavioral scores strongly, suggesting a causal relation between the neurobehavioral function and the restoration of barrier integrity as a result of the ongoing repair and recovery processes within the injured cords.