A useful tool for the initial assessment of blood-brain barrier permeability after traumatic brain injury in rabbits: dynamic contrast-enhanced magnetic resonance imaging.

Objective: The aim of this study was to evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and its quantitative coefficient (K(trans)) in the assessment of the extent of traumatic brain injury (TBI) in a rabbit model.

Methods: A weight-drop device (height, 20 cm) was used with varying impact force, 30-, 60-, or 90-g weight, to induce mild, moderate, or severe TBI, respectively. DCE-MRI and T2-weighted MRI was used to examine the injured groups and a sham group 1 day after TBI. We analyzed the relationship between K(trans) and the lesion volume on the basis of T2-weighted images in each group.

Results: The lesion volumes in both the severe and the moderate injury groups were greater than those observed in the mild injury group (p < 0.01). Furthermore, the lesion volumes in the severe injury group tended to be greater than those seen in the moderate injury group (p = 0.053). The K(trans) values in all injury groups were greater than those observed in the sham group (p < 0.01). In addition, the K(trans) values in the severe and moderate injury groups were greater than those of the mild injury group (p < 0.01), and the values seen in the severe injury group tended to be greater than those of the moderate injury group (p = 0.08). Moreover, we observed a correlation between the K(trans) value and lesion volume in all injury groups (mild injury group: r = 0.766, p = 0.01; moderate injury group: r = 0.731, p = 0.04; and severe injury group: r = 0.886, p = 0.019).

Conclusions: DCE-MRI and its quantitative coefficient, K(trans), have the potential to accurately assess the blood-brain barrier and the extent of injury in an in vivo model of TBI.