Should all suspected concussions be imaged with computed tomography (CT) scans?

Management of Suspected Concussions: Imaging Recommendations

Not all suspected concussions require imaging with CT scans. Instead, imaging decisions should be guided by validated clinical decision rules that identify patients at higher risk for clinically significant intracranial injuries 1.

Evidence-Based Approach to Imaging in Suspected Concussion

When to Image

CT imaging is indicated in suspected concussion patients with:

• High-risk features (100% sensitive for neurosurgical intervention) 1, 2:

  • Failure to reach GCS of 15 within 2 hours
  • Suspected open skull fracture
  • Any sign of basilar skull fracture
  • Vomiting >2 episodes
  • Age >60-65 years
  • Drug or alcohol intoxication
  • Deficits in short-term memory
  • Physical evidence of trauma above the clavicle
  • Post-traumatic seizure
  • Focal neurologic deficit
  • Coagulopathy

• Medium-risk features (98.4% sensitive for clinically important brain injury) 1, 3:

  • Amnesia before impact >30 minutes
  • Dangerous mechanism of injury

When to Avoid Imaging

CT imaging can be safely avoided in patients with:

• Minimal head trauma without loss of consciousness (LOC) or post-traumatic amnesia (PTA) who don't meet any of the above criteria 1
• Normal neurological examination without high-risk features 1, 2

Special Considerations

Pediatric Patients

For children with suspected concussion, the American Academy of Pediatrics recommends neuroimaging only when there is concern for structural brain abnormality 1. Clinical assessment should include mental status, balance, and cognitive function evaluation.

Imaging Modality Selection

• CT scan: First-line imaging for acute evaluation of suspected concussion with concerning features 1, 4

  • Advantages: Fast, widely available, highly sensitive for acute hemorrhage and skull fractures
  • Limitations: Radiation exposure, less sensitive for subtle injuries

• MRI: Generally not indicated for initial evaluation of concussion 1, 4

  • Consider MRI when:
    • Initial CT is normal but neurologic symptoms persist
    • Evaluation is in the subacute or chronic phase (>48 hours after injury)
    • More detailed assessment of white matter injury is needed

Clinical Pitfalls to Avoid

1. Overutilization of CT: Mathematical models show that selective CT scanning with high-sensitivity clinical decision rules is more effective than "CT all" strategies 1. Using validated decision rules can reduce unnecessary imaging by 32-61% 1, 5.

2. Underutilization of CT: Failing to image patients with high-risk features can miss critical injuries requiring intervention. The Canadian CT Head Rule and New Orleans Criteria both have essentially 100% sensitivity for detecting injuries requiring neurosurgical intervention 1, 3.

3. Relying solely on GCS: Some patients with a GCS of 15 may still harbor significant intracranial injuries 2. A normal GCS should not be the only factor in deciding against imaging if other risk factors are present.

4. Delayed imaging in elderly patients: Age >60-65 years is an independent risk factor for intracranial injury. Delaying CT imaging in elderly patients with LOC significantly increases morbidity and mortality 2.

By following these evidence-based guidelines, clinicians can appropriately identify patients who require imaging while avoiding unnecessary radiation exposure and healthcare costs in those at low risk for clinically significant injury.