Subdural hematoma on CT is typically crescent-shaped. Which option reflects this?

Subdural hematoma on CT is typically crescent-shaped. Which option reflects this?

• A. Epidural hematoma
• B. Subdural hematoma
• C. Intracerebral hemorrhage
• D. Concussion

Answer: (B)

Bleeding between the dura and arachnoid tends to hug the brain surface, so on CT it forms a crescent-shaped collection. This crescent shape arises because the blood follows the contour of the cerebral cortex and is bounded by the dura and the skull, often extending across sutures but staying along the surface rather than forming a contained lens. In contrast, an epidural hematoma comes from a arterial bleed (often after a skull fracture) and appears as a lens- or biconvex-shaped collection that is typically limited by skull sutures and dural attachments. An intracerebral hemorrhage is located inside the brain tissue itself, appearing as an irregular or round intraparenchymal bleed within the brain substance. A concussion would not show a focal bleed on CT in many cases, or shows no acute hemorrhage. So the crescent-shaped appearance on CT corresponds to a subdural hematoma.

Bleeding between the dura and arachnoid tends to hug the brain surface, so on CT it forms a crescent-shaped collection. This crescent shape arises because the blood follows the contour of the cerebral cortex and is bounded by the dura and the skull, often extending across sutures but staying along the surface rather than forming a contained lens.

In contrast, an epidural hematoma comes from a arterial bleed (often after a skull fracture) and appears as a lens- or biconvex-shaped collection that is typically limited by skull sutures and dural attachments. An intracerebral hemorrhage is located inside the brain tissue itself, appearing as an irregular or round intraparenchymal bleed within the brain substance. A concussion would not show a focal bleed on CT in many cases, or shows no acute hemorrhage.

So the crescent-shaped appearance on CT corresponds to a subdural hematoma.