Which imaging features on CT/MRI are associated with worse prognosis after TBI?

• A. Isolated skull fracture without edema
• B. Narrowing of ventricles without edema
• C. Isolated small subdural hematoma
• D. Diffuse cerebral edema, midline shift, compressed or absent basal cisterns, brainstem injury, large hematomas

Answer: (D)

Imaging signs of brain swelling with mass effect are the strongest indicators of poor prognosis after TBI. Diffuse cerebral edema means widespread swelling that raises intracranial pressure and worsens cerebral perfusion, setting the stage for secondary injury. Midline shift shows substantial mass effect from swelling or a large lesion, indicating that the brain is being pushed off its normal position, which raises the risk of brain herniation and further injury. Compressed or absent basal cisterns reflect raised intracranial pressure with diminished space around the brainstem, a cue that brainstem function may be compromised and deterioration can occur rapidly. Brainstem injury seen on imaging points directly to damage of vital autonomic and motor control centers, correlating strongly with a poor neurological outcome. Large hematomas contribute significant mass effect and ongoing bleeding, further increasing ICP and the chance of deterioration.

In contrast, findings like an isolated skull fracture without edema or a small, nonexpanding subdural hematoma without edema do not by themselves carry the same weight for predicting poor outcome, because they represent limited injury without the widespread swelling or mass effect that drives worse prognosis.