Canadian CT Head Rule


Whether or not to perform a head CT for a MINOR head injury




High risk (possible neurological intervention):

  • GCS score <15 at 2 hrs post-injury
  • Suspected open or depressed skull fracture
  • Any sign of basal skull fracture
    • hemotympanum
    • Racoon Eyes
    • Battle’s sign
    • CSF otorrhea and/or rhinorrhea
  • Vomiting > 1 episodes
  • Age > 64 years

Medium risk (possible brain injury noted on CT):

  • Retrograde amnesia before impact > 30 min
  • Dangerous mechanism
    • pedestrian struck by vehicle
    • ejection from a vehicle
    • fall >3 feet or >5 steps
Rule does not apply:
  • Non-trauma cases
  • GCS <13
  • Age <16
  • Coumadin or bleeding disorder
  • Obvious open skull fracture


CT If any of the high risk or medium risks are present.  In most cases where the rule does not apply, you will likely be doing a CT anyway.


Stiell IG, Wells GA, Vandemheen K, Clement C, Lesiuk H, Laupacis A, McKnight RD, Verbeek R, Brison R, Cass D, Eisenhauer MA, Greenberg GH, Worthington J, for the CCC Study Group. The Canadian CT Head Rule for patients with minor head injury. The Lancet. 2001 May 5;357(9266):1391-6.