Emergency Medicine Decision rule Strong evidence Clinical review pending v1.0.0

Canadian CT Head Rule

Does an adult with minor head injury need a CT head?

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Applicability

Minor head injury: witnessed loss of consciousness, definite amnesia or witnessed disorientation, with GCS 13–15

No exclusion criteriaExclusions: age < 16, anticoagulation or bleeding disorder, obvious open skull fracture, seizure after injury, focal neurological deficit, unstable vital signs, pregnancy, returned for reassessment of the same injury.

High-risk factors

GCS < 15 at 2 hours after injury

Suspected open or depressed skull fracture

Any sign of basal skull fractureHaemotympanum, 'raccoon' eyes, CSF otorrhoea/rhinorrhoea, Battle's sign.

Vomiting ≥ 2 episodes

Age ≥ 65 years

Medium-risk factors

Retrograde amnesia ≥ 30 minutes before impact

Dangerous mechanismPedestrian struck by motor vehicle, occupant ejected, or fall from > 3 ft (0.9 m) or > 5 stairs.

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About this tool

Decision rule using five high-risk and two medium-risk factors to identify adults with minor head injury who need CT imaging.

Intended use

Adults (≥ 16 years) with minor head injury (GCS 13–15) and witnessed LOC, amnesia or disorientation.

Outcome

Need for neurosurgical intervention; clinically important brain injury on CT

Time horizon

Index visit

Derivation population

Canadian emergency departments.

Do not use in

Age < 16, anticoagulation or bleeding disorder, seizure, focal deficit, unstable vitals, pregnancy.

Limitations

Not applicable to anticoagulated patients.
Clinicians must still apply judgement for social and follow-up factors.

Clinical problems

Head and neck trauma

Evidence

Evidence level

Strong evidence

Derived and externally validated in multiple cohorts (including prospective studies) and incorporated into major clinical guidelines. Methodology

Guideline status

Forms the basis of CT imaging criteria in several national head-injury guidelines (e.g. NICE).

Validation studies

Derivation (Stiell 2001)

3,121 patientsProspective

Adults with minor head injury, 10 Canadian EDs

High-risk factors: 100% sensitivity for need for neurosurgical intervention. High- plus medium-risk factors: 98.4% sensitivity for clinically important brain injury.

Evidence summaries for this tool are awaiting independent clinical review. Statistics are shown only where they could be attributed to a specific publication.

References

Original publicationStiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet 2001;357:1391-1396. Find on PubMed (opens in a new tab)
Validation studyStiell IG, Clement CM, Rowe BH, et al. Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury. JAMA 2005;294:1511-1518. Find on PubMed (opens in a new tab)

Version history

Version	Formula	Effective	Reviewer	Changes
v1.0.0	Stiell 2001	2026-10-03	—	Initial implementation with reference test vectors.

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Clinical decision support only. Interpret results in the context of the individual patient and current guidance; HumanPulse does not replace professional medical judgment.