A 28-year-old man is brought to the emergency department following a road traffic accident. On arrival, he is alert and oriented, GCS 15/15. He complains of severe frontal headache and mild neck pain. On examination, there is a small laceration on the forehead but no focal neurological deficit. Which investigation is most appropriate as the next step to rule out intracranial injury?

## Investigation of Choice in Head Injury with GCS 15 **Key Point:** Non-contrast CT head is the gold standard first-line imaging in acute head injury, regardless of GCS score, to detect acute intracranial pathology (epidural hematoma, subdural hematoma, subarachnoid hemorrhage, contusion, diffuse axonal injury). ### Why CT is Superior in Acute Trauma | Feature | CT Head | MRI Brain | Skull X-ray | LP | |---------|---------|-----------|-------------|----| | **Speed** | <5 min | 30–45 min | <2 min | Invasive | | **Detects acute bleed** | Yes (hyperdense) | Yes but slower | No | Yes but late | | **Bone fractures** | Excellent | Poor | Limited | No | | **Availability** | Always available | Limited in trauma | Outdated | Contraindicated | | **Radiation** | Yes | No | Yes | N/A | | **Acute phase use** | **Gold standard** | Delayed imaging | Not recommended | Contraindicated | **High-Yield:** In ATLS protocol, non-contrast CT head is the standard of care for any head injury with mechanism of injury, loss of consciousness, or persistent symptoms—even with normal GCS. ### Clinical Pearl A GCS of 15 does **not** exclude intracranial injury. Up to 5–10% of patients with GCS 15 may have significant intracranial pathology on CT. Headache and neck pain in the context of trauma mandate imaging. **Warning:** Do not delay CT imaging based on normal GCS or lack of focal signs. Epidural hematomas can present with lucid intervals and normal initial exam. ### Timing CT should be performed **immediately** in the trauma bay or resuscitation area as part of the secondary survey (ATLS protocol).