The Canadian CT Head Rule1 is a validated aid for deciding whether a head CT should be performed in a patient with a mild traumatic brain injury.
Inclusion and exclusion criteria
The Canadian CT Head Rule cannot be applied to all patients, and the following inclusion and exclusion criteria must be observed:
| Inclusion criteria | Exclusion criteria |
|---|---|
| Loss of consciousness | Anticoagulation |
| GCS 13-15 | Bleeding tendency |
| Confusion | Younger than 16 years |
| Amnesia | Seizure |
Based on 3121 patients2, the following high- and medium-risk factors were identified:
| High-risk factors | Medium-risk factors |
|---|---|
| GCS <15 for 2 hours after trauma | Posttraumatic amnesia > 30 minutes |
| Suspected open skull fracture | Dangerous mechanism of injury defined as: <br /> - Pedestrian struck by a motor vehicle <br /> - Ejection of the driver from a motor vehicle <br /> - Fall from a height > 3 feet or 5 stairs |
| More than two episodes of vomiting | |
| Age > 65 years |
Interpretation
If the patient meets the inclusion criteria and none of the above risk factors are present, a head CT is not necessary according to the Canadian Head CT Rule. If any of the high- or medium-risk factors is present, a head CT should be performed.
References