A 35-year-old man is brought to the trauma center with acute severe head injury following a motor vehicle collision. He is drowsy and has a blown right pupil. Non-contrast CT head shows a lens-shaped hyperdensity in the right frontoparietal region that does not cross the midline but does not respect the suture lines. The neurosurgeon needs rapid confirmation of the diagnosis and exact location for emergency burr hole placement. Which investigation is most appropriate?

Explanation

## Clinical Presentation & Diagnosis The patient has **acute epidural hematoma** with signs of increased intracranial pressure (blown pupil = uncal herniation): - **Lens-shaped (biconvex) hyperdensity** — pathognomonic for epidural - **Does not cross midline** — respects falx - **Does not respect suture lines** — epidural collections are not confined by dural attachments at sutures - **Acute presentation** (minutes to hours post-trauma) — typical for arterial bleeding (middle meningeal artery) ### Why Repeat Non-Contrast CT with 3D Reconstruction Is Most Appropriate **Key Point:** In acute epidural hematoma requiring **emergency surgical evacuation**, the investigation of choice is: 1. **Rapid non-contrast CT** — already done; confirms diagnosis 2. **3D reconstruction** — provides precise anatomical localization for burr hole placement 3. **Bone windowing** — identifies skull fracture (often associated with epidural) and helps surgeon plan approach **High-Yield:** The diagnosis is already established by the initial non-contrast CT (lens-shaped, acute). The neurosurgeon does NOT need additional imaging modalities; they need **precise 3D localization** of the hematoma relative to skull landmarks for **rapid surgical access**. Time is brain — every minute of delay increases mortality in epidural hematoma. **Clinical Pearl:** Epidural hematoma is a **neurosurgical emergency**. The patient is already showing signs of herniation (blown pupil). The imaging strategy must be: - **Confirm diagnosis** ✓ (already done with initial CT) - **Localize precisely** → 3D CT reconstruction - **Plan surgical approach** → bone windowing - **Avoid delays** → do NOT do MRI (takes 30–60 min; patient may herniate) ## Why Each Investigation Is Chosen or Rejected | Investigation | Acute Epidural | Rationale | |---|---|---| | **Non-contrast CT + 3D recon + bone window** | ✓ BEST | Rapid, confirms diagnosis, provides surgical roadmap, no delay | | **MRI (FLAIR/SWI)** | ✗ | Takes 30–60 min; patient is herniation risk; MRI not superior to CT for acute blood | | **CTA** | ✗ | Useful for vascular injury (pseudoaneurysm), not for hematoma localization | | **Intraoperative ultrasound** | ✗ | Adjunct during surgery, not a diagnostic tool; cannot replace preoperative imaging | **Mnemonic: EPIDURAL EMERGENCY = **E**arly **P**resentation, **I**ncreased **ICP**, **D**iagnosis by **CT**, **U**rgent **R**esection, **A**void **L**ong imaging (MRI), **E**mergency **R**econstruction (3D) for surgical planning. [cite:Neuroradiology: Traumatic Brain Injury, Osborn's Brain Imaging]