Epidural Hematoma (EDH) — CT Brain (Non-contrast)
Core CT Features (Acute EDH)
- Shape: Biconvex / lentiform (lens-shaped)
- Density: Homogeneous hyperdense (acute blood)
- Location: Extra-axial, between skull and dura
- Suture relation: Does NOT cross sutures (tight dural attachment)
(may cross dural reflections rarely if large) - Midline shift / mass effect: Common → sulcal effacement, ventricular compression
- Underlying skull fracture: Frequently present (esp. temporal bone)
Additional Signs
- “Swirl sign” → hypodense areas within hematoma (active bleeding)
- Lucid interval correlation (clinical, not CT but supportive)
- Effacement of cisterns if severe
Evolution
- Acute (0–3 days): Hyperdense
- Subacute: Isodense → may be missed without contrast
- Chronic (rare for EDH): Hypodense
Key Differentiation (vs SDH)
- EDH → Biconvex, limited by sutures
- SDH → Crescentic, crosses sutures but not midline (falx limit)
Rapid Mnemonic
“EDH = Egg-shaped, Does NOT cross sutures, High density”


