The Canadian CT Head Rule (CCHR) is a clinical decision aid designed to guide healthcare professionals in determining whether a computed tomography (CT) scan of the head is necessary for patients with minor head injuries. It helps identify patients who are at high risk for neurosurgical intervention or who may benefit from CT imaging to detect brain injuries.

Exclusion Criteria:

The CCHR does not apply to patients who:

Did not experience trauma.

Have a Glasgow Coma Scale (GCS) score lower than 13.

Are younger than 16 years old.

Are taking warfarin or have a bleeding disorder.

Have an obvious open skull fracture.

High Risk Criteria:

Patients with any of the following criteria are considered at high risk for neurosurgical intervention and may require CT imaging:

Glasgow Coma Scale (GCS) score lower than 15 at 2 hours after injury.

Suspected open or depressed skull fracture.

Any sign of basal skull fracture, such as hemotympanum, raccoon eyes, cerebrospinal fluid (CSF) otorrhea or rhinorrhea, or Battle’s sign.

Two or more episodes of vomiting.

65 years or older.

Medium Risk Criteria:

Patients with the following criteria are considered at medium risk for brain injury detection by CT imaging and may also benefit from CT scanning:

Amnesia before impact lasting 30 minutes or more.

Involvement in a "dangerous" mechanism, such as being a pedestrian struck by a motor vehicle, being ejected from a motor vehicle, or experiencing a fall from an elevation of 3 feet or more, or 5 stairs.