Magnetic resonance imaging study of experimental acute spinal cord injury

Magnetic resonance imaging (MRI) has been used widely in the diagnosis of acute spinal cord injuries. The association between MRI findings and histologic changes, however, remains unclear. Using a rabbit spinal cord injury model, the authors compared the MRI and histologic abnormalities as they evolved over the first post-trauma month. Bleeding in the gray matter, visualized as a low-intensity area on T1-weighted views and high-intensity area on T2-weighted views, observed immediately after injury, disappeared within the first week. Edema, appearing 6 hours after the initial injury and seen as a high-intensity T2-weighted MRI image, became maximal 1 week later and gradually decreased thereafter. Also appearing 1 week later, were necrotic changes in the gray matter, corresponding to low signals on T1-weighted studies but high signals on T2-weighted studies. MRI therefore helped differentiate hemorrhage and necrosis, presumably irreversible lesions, from the more reversible findings related to edema.