Which CT finding is characteristic of diffuse axonal injury?

Which CT finding is characteristic of diffuse axonal injury?

• A. Widespread white matter microhemorrhages at gray–white junction
• B. Epidural hematoma
• C. Subdural hematoma
• D. Temporal lobe contusion

Answer: (A)

Diffuse axonal injury results from rapid acceleration–deceleration that twists and shears axons across white matter tracts. The CT hallmark of this widespread injury is tiny hemorrhages scattered in the white matter, especially at the gray–white junction, and can extend to the corpus callosum or brainstem in more severe cases. These punctate microhemorrhages reflect microvascular damage from the shear forces acting on axons. This pattern stands apart from focal, space-occupying bleeds or contusions. An epidural hematoma is a lens-shaped collection from arterial injury, a subdural hematoma is a crescent-shaped collection from bridging-vein injury, and a temporal lobe contusion is a localized bruise. DAI tends to present with diffuse brain dysfunction and may have a normal initial CT, with MRI being more sensitive for detecting the extent of axonal injury.

Diffuse axonal injury results from rapid acceleration–deceleration that twists and shears axons across white matter tracts. The CT hallmark of this widespread injury is tiny hemorrhages scattered in the white matter, especially at the gray–white junction, and can extend to the corpus callosum or brainstem in more severe cases. These punctate microhemorrhages reflect microvascular damage from the shear forces acting on axons. This pattern stands apart from focal, space-occupying bleeds or contusions. An epidural hematoma is a lens-shaped collection from arterial injury, a subdural hematoma is a crescent-shaped collection from bridging-vein injury, and a temporal lobe contusion is a localized bruise. DAI tends to present with diffuse brain dysfunction and may have a normal initial CT, with MRI being more sensitive for detecting the extent of axonal injury.