Canadian CT head rule calculator
Canadian CT Head Rule
| High Risk (for neurosurgical intervention) | ||
|---|---|---|
| Criteria | No | Yes |
| GCS <15 at 2 hours after injury | 1 | |
| Suspected open or depressed skull fracture | 1 | |
| Any sign of basal skull fracture (hemotympanum, raccoon eyes, CSF otorrhea/rhinorrhea, Battle sign) | 1 | |
| Vomiting ≥2 episodes | 1 | |
| Age ≥65 years | 1 | |
| Medium Risk (for brain injury on CT) | ||
| Amnesia before impact >30 min | 1 | |
| Dangerous mechanism (pedestrian struck, occupant ejected, fall from ≥3 feet or ≥5 stairs) | 1 | |
| High Risk Criteria | / 5 | |
| Medium Risk Criteria | / 2 | |
| Interpretation | |
|---|---|
| All No | CT NOT required — Low risk for clinically important brain injury. Safe for discharge with head injury instructions. |
| Medium risk ≥1 | CT recommended — Risk of brain injury on CT. Imaging indicated. |
| High risk ≥1 | CT required — High risk for neurosurgical intervention. Urgent CT head. |
| References |
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