Diffuse axonal injury (DAI) is a microscopic description of the primary damage to brain parenchyma seen after severe closed head injury. Widespread axonal damage is caused by rotational forces and deceleration, particularly in the deep white
matter of the cerebral hemisphere and midbrain. The characteristic pathological lesion is axonal bulb formation. CT imaging may be normal or show petechial hemorrhages in the midbrain (Duret hemorrhages), corpus callosum or deep hemispheric white matter. MR imaging is more sensitive and demonstrates punctate areas of increased T2 signal, suggestive of localized axonal damage and edema, in deep white matter. The clinical course of severe DAI typically involves coma and often raised intracranial pressure, with risk for secondary injury.
Was this article helpful?