On CT imaging, subdural hematoma typically appears as which shape?

• A. Lens-shaped bleed
• B. Diffuse patchy low-density areas
• C. Crescent-shaped bleed that can cross suture lines
• D. Round, uniform hyperdensity

Answer: (C)

Subdural hematoma on CT is best recognized by a crescent-shaped collection that follows the surface of the brain and can extend across suture lines. This crescent shape arises because the blood accumulates in the subdural space between the dura and arachnoid, spreading along the brain’s convolutions and not being confined by skull sutures. This distinguishes it from an epidural hematoma, which is typically lens-shaped and confined by sutures. A diffuse patchy low-density pattern would suggest edema or multiple contusions rather than a discrete subdural collection, and a round, uniform hyperdensity points to a different type of hemorrhage.