Which of the following CT findings is most specific for acute epidural hematoma?

Explanation

## Epidural Hematoma: Imaging Signature **Key Point:** Epidural hematoma (EDH) classically presents as a **lens-shaped (biconvex) collection** that does NOT cross suture lines, because blood accumulates between the dura and inner table of the skull. ### Pathoanatomic Basis - **Location:** Between dura mater and inner table of calvarium - **Boundary:** Confined by dural attachments at suture lines - **Shape:** Lens-shaped or biconvex (convex on both sides) - **Crossing:** Does NOT cross sutures (dura is adherent to sutures) ### CT Characteristics | Feature | Epidural Hematoma | Subdural Hematoma | |---------|-------------------|-------------------| | **Shape** | Lens-shaped (biconvex) | Crescent-shaped (concave inner margin) | | **Crosses sutures?** | No | Yes | | **Crosses midline?** | No (respects falx) | Yes (can cross falx) | | **Density** | Hyperdense (acute) | Hyperdense (acute) | | **Common location** | Temporal (MMA injury) | Frontal/parietal | | **Mechanism** | Arterial (MMA) | Venous (bridging veins) | ### Clinical Correlation - **Classic presentation:** Lucid interval (loss of consciousness → recovery → deterioration) - **Urgency:** Epidural hematoma is a neurosurgical emergency; requires evacuation - **Prognosis:** Better if diagnosed early; mortality ~5–10% with prompt treatment **High-Yield:** The **lens-shaped, non-suture-crossing** appearance is pathognomonic for epidural hematoma and is a high-yield imaging sign on NEET PG. **Mnemonic:** **LENS-EDH** = Lens-shaped, Epidural, Does not cross sutures, Hemorrhage. **Clinical Pearl:** A temporal epidural hematoma with a lucid interval is a classic presentation in trauma; imaging must be obtained urgently before clinical deterioration occurs. [cite:Osborn AG, Salzman KL, Barkovich AJ. Diagnostic Imaging: Brain. 3e, Ch 2]