The Canadian CT head rule (CCTHR) is a validated clinical decision rule to determine the need for CT head in adult emergency department patients with minor head injuries.
Patient has suffered minor head trauma with resultant:
- loss of consciousness
- GCS 13-15
- amnesia after the event
- anticoagulant medication or bleeding disorder
- age <16 years
The initial study was carried out in 10 Canadian emergency departments amongst 3121 patients. Five high risk factors and two medium risk factors were identified to predict the need for subsequent neurosurgical intervention 1.
High risk factors
- GCS <15 two hours post injury
- suspected open skull fracture
- sign of base of skull fracture
- vomiting more than twice
- age >65 years
Medium risk factors
- amnesia post event >30 min
- dangerous mechanism of injury
- pedestrian struck by motor vehicle
- occupant ejected from motor vehicle
- fall from >3 feet or 5 stairs
If the patient does not have any of the risk factors identified by the CCTHR then the CT head is deemed unnecessary. If any of the above risk factors are identified then a CT head should be obtained.
Several studies have found the CCTHR to be highly sensitive in identifying injuries requiring neurosurgical intervention (80-100%) 1-5, with varying degrees of specificity (49.6-80.7%)1-5.
- 1. Stiell IG, Wells GA, Vandemheen K, Clement C, Lesiuk H, Laupacis A, McKnight RD, Verbeek R, Brison R, Cass D, Eisenhauer ME, Greenberg G, Worthington J. The Canadian CT Head Rule for patients with minor head injury. Lancet (London, England). 357 (9266): 1391-6.
- 2. Stiell IG, Clement CM, Rowe BH, Schull MJ, Brison R, Cass D, Eisenhauer MA, McKnight RD, Bandiera G, Holroyd B, Lee JS, Dreyer J, Worthington JR, Reardon M, Greenberg G, Lesiuk H, MacPhail I, Wells GA. Comparison of the Canadian CT Head Rule and the New Orleans Criteria in patients with minor head injury. JAMA. 294 (12): 1511-8.
- 3. Wolf H, Machold W, Frantal S, Kecht M, Pajenda G, Leitgeb J, Widhalm H, Hajdu S, Sarahrudi K. Risk factors indicating the need for cranial CT scans in elderly patients with head trauma: an Austrian trial and comparison with the Canadian CT Head Rule. Journal of neurosurgery. 120 (2): 447-52.
- 4. Papa L, Stiell IG, Clement CM, Pawlowicz A, Wolfram A, Braga C, Draviam S, Wells GA. Performance of the Canadian CT Head Rule and the New Orleans Criteria for predicting any traumatic intracranial injury on computed tomography in a United States Level I trauma center. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 19 (1): 2-10.
- 5. Bouida W, Marghli S, Souissi S, Ksibi H, Methammem M, Haguiga H, Khedher S, Boubaker H, Beltaief K, Grissa MH, Trimech MN, Kerkeni W, Chebili N, Halila I, Rejeb I, Boukef R, Rekik N, Bouhaja B, Letaief M, Nouira S. Prediction value of the Canadian CT head rule and the New Orleans criteria for positive head CT scan and acute neurosurgical procedures in minor head trauma: a multicenter external validation study. Annals of emergency medicine. 61 (5): 521-7