Epidural Hematoma, Variant

KEY FACTS

Terminology

• “Typical” epidural hematoma (EDH)

  • Arterial laceration

  • 90-95% supratentorial (temporoparietal most common)

  • Biconvex, unilateral

• Atypical EDH

  • Unusual etiology

  • Unusual location

  • Unusual shape or density

Imaging

• Venous EDH (10% of EDHs)

  • Fracture (linear, diastatic) crosses dural venous sinus

  • Skull base, vertex

  • Easily overlooked

  • Coronal, sagittal reformats key to diagnosis

• Anterior temporal EDH (10% of EDHs)

  • Middle cranial fossa

    • –

      In front of, not lateral to, temporal lobe

  • Fracture crosses sphenoparietal sinus

  • Generally asymptomatic (1-2 cm, stable size)

  • No reported cases requiring surgery

• Vertex EDH (1-2% of EDHs)

  • Fracture crosses, lacerates superior sagittal sinus

  • Accumulates slowly

  • Symptoms often delayed

  • Easily overlooked, size underestimated on axial CT

  • Coronal, sagittal reformatted images key

• Clival EDH (< 1% of EDHs)

  • Lacerates clival venous plexus

  • Self-limited; dura tightly attached, so rarely large

  • Asymptomatic unless associated vascular, cranial nerve injury

  • Biconvex hyperdensity immediately posterior to clivus

  • Sagittal reformatted images key to diagnosis

TERMINOLOGY