Canadian CT Head Rule

CT Head Rule is only required for application in patients with minor head injuries who have any one of the following:
High risk (for neurologic intervention)

1. GCS score <15>
2. Suspected open or depressed skull fracture
3. Any sign of basal skull fracture (hemotympanum, "raccoon" eyes, cerebrospinal fluid otorrhoea/rhinorrhea, Battle's sign)
4. Vomiting >=two episodes
5. Age >=65 years

Medium risk (for brain injury on CT)

1. Amnesia before impact >30 minutes
2. Dangerous mechanism (pedestrian struck by motor vehicle, occupant ejected from motor vehicle, fall from height >3 feet or five stairs)

NOTE: Minor head injury is defined as witnessed loss of consciousness, definite amnesia or witnessed disorientation in a patient with a GCS score of 13 to 15.

CT = computed tomography; GCS = Glasgow Coma Scale.
From Stiell IG, Wells GA, Vandemheen K, Clement C, Lesiuk H, Laupacis A, et al. The Canadian CT head rule for patients with minor head injury. Lancet 2001;357:1394.