Concept:
Traumatic brain injury (TBI) from road traffic accidents (RTA) in children commonly results in extra-axial intracranial hemorrhages.
Non-contrast head CT is the gold standard imaging modality for distinguishing epidural hematoma (EDH) from subdural hematoma (SDH) and intraparenchymal contusions.
Explanation:
• Epidural Hematoma (EDH):
- Results from arterial bleeding, most classically rupture of the middle meningeal artery associated with a temporal/parietal bone fracture.
- Appears on CT as a classic well-defined, hyperdense, biconvex (lenticular) collection.
- The hematoma is confined by the tight adherence of the dura mater to the cranial sutures, so it does not cross cranial suture lines (but can cross the falx/tentorium).
• Subdural Hematoma (SDH):
- Results from tearing of bridging cortical veins.
- Appears as a crescent-shaped (concavo-convex) hyperdense collection that crosses cranial sutures along the hemisphere, limited only by dural reflections (falx cerebri).
• Intraparenchymal Hemorrhage:
- Appears as hyperdense hemorrhagic foci within the brain parenchyma itself, typically associated with surrounding edema.
Final Answer:
The classic biconvex, lenticular hyperdense lesion limited by cranial sutures on head CT following trauma is diagnostic of an Epidural Hematoma (EDH).