Diagnosis:

CT:

• Cerebral edema (hypodensity on CT) in the cortex or lobe at  the site of injury or opposite location (counter-coup) or distant site where impact occurs at areas of the skull
• Hemorrhage (hyperdensity on CT) within the areas of contusion are typical. They involve the cortex and extend subcortically to a variable extent
• Frontal lobes (orbitofrontal) and temporal lobes (anterior temporal) are common locations
• Associated with other features of traumatic brain injury such as traumatic subarachnoid hemorrhage (common), subdural hematoma or extradural hematoma

MRI:

• Mirrors above findings on CT, but is more sensitive
• GRE: very sensitive for associated hemorrhages and diffuse axonal injury
• DWI: may show diffuse axonal injury in addition
• T2/FLAIR: cortical and subcortical cerebral edema with hemorrhage

Pathology:

• Disruption of cortex with adherent blood acutely. Tan grey if old. Inferior frontal & temporal lobes usually. Gliding contusions occur in parasagittal white matter.
• Microscopically: acutely hemorrhage, perpendicular to cortex. Chronically hemosiderin, macrophages, disrupted cortex.

Treatment:

• Medical treatment of ICP and osmolar agents as necessary for cerebral edema
• Uncommonly requires surgery: if so usually decompressive craniotomy to allow for space as the edema progresses then resolves