Figure 11. CT and MR appearance of brainstem injury with diffuse axonal injury.

Axial noncontrast CT (A) and T2*-weighted MPGR MR (B,C) images of 27-year-old man reveal posttraumatic brainstem injury. Hemorrhagic axonal injury in the midbrain tegmentum appears as rounded hyperdensity on CT (A, arrow) and as a focal area of susceptibility on MPGR sequence (B, arrow). Caudally, an axial MPGR image through the pons (C) reveals multiple additional foci of susceptibility in the dorsal pons that were not apparent on CT. Numerous additional foci of abnormal susceptibility (B,C) are present in the bilateral temporal supratentorial and infratentorial white matter consistent with diffuse axonal injury. Also note traumatic injuries including a right tentorial subdural hematoma (white arrowheads) and a left anterior temporal contusion (black arrowheads), which are better appreciated on MR (C) than CT (A).