What are the criteria for performing a non‑contrast head CT in adult patients?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: November 9, 2026 • View editorial policy

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question

Head CT Criteria for Adults

Non-contrast head CT should be performed in adult trauma patients based on validated clinical decision rules, with the Canadian CT Head Rule and New Orleans Criteria being the gold standards for determining which patients require imaging. 1, 2

Clinical Decision Framework

The approach differs based on whether the patient experienced loss of consciousness (LOC) or post-traumatic amnesia (PTA):

For Patients WITH LOC or PTA (Level A - New Orleans Criteria)

Order head CT if ANY of the following are present: 2

  • Headache
  • Vomiting
  • Age >60 years
  • Drug or alcohol intoxication
  • Deficits in short-term memory
  • Physical evidence of trauma above the clavicle
  • Post-traumatic seizure
  • GCS score <15
  • Focal neurologic deficit
  • Coagulopathy (including anticoagulant medications like warfarin)

This approach has 100% sensitivity (95% CI 95-100%) for detecting injuries requiring intervention, though specificity is only 25%. 1

For Patients WITHOUT LOC or PTA (Level B - Canadian CT Head Rule Modified)

Consider head CT if ANY of the following are present: 2

  • Focal neurologic deficit
  • Vomiting
  • Severe headache
  • Age ≥65 years
  • Physical signs of basilar skull fracture (Battle's sign, raccoon eyes, hemotympanum, CSF leak)
  • GCS score <15
  • Coagulopathy
  • Dangerous mechanism of injury (ejection from vehicle, pedestrian struck, fall >3 feet or 5 stairs)

High-Risk Factors (Canadian CT Head Rule)

The following five factors are 100% sensitive (95% CI 92-100%) for predicting need for neurosurgical intervention: 1

  • Failure to reach GCS 15 within 2 hours
  • Suspected open skull fracture
  • Sign of basal skull fracture
  • Vomiting more than once
  • Age >64 years

Severity-Based Approach

Mild Head Injury (GCS 13-15)

Apply the clinical decision rules above. CT is NOT routinely indicated if none of the criteria are met. 2

Moderate Head Injury (GCS 9-12)

CT is always indicated. 2

Severe Head Injury (GCS 3-8) or Penetrating Trauma

CT is always indicated. 2

Important Caveats

Coagulopathy deserves special attention: Most guidelines recommend CT for all head trauma patients on anticoagulants (warfarin, DOACs), though controversy exists regarding antiplatelet therapy alone or minimal trauma. When in doubt, err toward imaging. 2

Age thresholds vary slightly: The New Orleans Criteria uses >60 years while the Canadian rule uses ≥65 years. The more conservative (lower) age threshold is safer. 2

These rules apply to patients ≥16 years old. Pediatric patients require different criteria. 2

Intoxication is tricky: While intoxication is a criterion for imaging in patients with LOC/PTA, it can mask neurologic findings. Maintain a low threshold for imaging in significantly intoxicated patients even without clear LOC. 2

What NOT to Order

Do not order: 2

  • Skull radiographs (replaced by CT, which is far more sensitive)
  • MRI for acute trauma (no role in initial evaluation)
  • CT angiography (unless vascular injury suspected)
  • PET/CT, MR spectroscopy, functional MRI, or DTI (no role in acute setting)

Follow-Up Imaging

Repeat CT is indicated for: 2

  • New or progressive neurologic deficits
  • Patients with initial positive findings and clinical deterioration

Repeat CT may NOT be needed for: 2

  • Stable patients with normal neurologic exam and small hemorrhages (<10 mL)

References

2
Guideline

acr appropriateness criteria® head trauma: 2021 update.

Journal of the American College of Radiology, 2021

Related Questions

When is an emergent non‑contrast head CT indicated for a patient with acute neurological changes or recent head trauma?
Can you teach me how to read a non‑contrast head CT?
Does a 70-year-old patient who struck his forehead on a cabinet require a head CT scan?
In a 73-year-old woman with headache and left-sided jaw pain after a ground-level fall onto the left side of her head, without loss of consciousness, what workup is indicated?
Does a 65-year-old female with a head injury one week ago, now experiencing mild brain fog and dizziness but no other symptoms and no prior imaging, require an urgent non‑contrast head CT?
What is the recommended sequence and choice of therapy for Parkinson disease?
How is Roux‑en‑Y reconstruction performed after gastrectomy for gastric cancer, including indications, limb length, and postoperative care?
What is the appropriate dosage of Wellbutrin XL (bupropion XL)?
Why is methotrexate contraindicated in patients with an estimated glomerular filtration rate (eGFR) below 60 mL/min/1.73 m²?
If tuberculosis is ruled out, what is the next oncologic plan for a patient who has completed four cycles of cisplatin‑based chemoradiation and now has new pulmonary lesions?
What is the term for a nocturnal panic attack that presents with sudden awakening, fright, palpitations, and transient elevation of blood pressure?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.