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Adapting the Canadian CT head rule age criteria for mild traumatic brain injury
  1. Nicolas Fournier1,2,
  2. Charles Gariepy1,2,
  3. Jean-François Prévost1,2,
  4. Vincent Belhumeur1,2,
  5. Émile Fortier1,2,
  6. Pierre-Hugues Carmichael3,
  7. Jean-Luc Gariepy4,
  8. Natalie Le Sage1,2,
  9. Marcel Émond1,2,5
  1. 1 Axe santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec - Université Laval, Quebec, Canada
  2. 2 Département de médecine familiale et de médecine d’urgence, Université Laval, Quebec, Canada
  3. 3 Centre d’excellence sur le vieillissement de Québec, Centre intégré universitaire de santé et de services sociaux de la Capitale-Nationale, Québec, Canada
  4. 4 Département de radiologie, CHU de Québec - Université Laval, Quebec, Canada
  5. 5 Centre de Recherche sur les Soins et Services de Première Ligne de l’Université Laval, Québec, Canada
  1. Correspondence to Dr Marcel Émond, CHU de Quebec - Universite Laval; marcelemond1{at}


Objective With the ageing population, the prevalence of mild traumatic brain injury (mTBI) among older patients is increasing, and the age criteria of the Canadian CT head rule (CCHR) is challenged by many emergency physicians. We modified the age criteria of the CCHR to evaluate its predictive capacity.

Methods We conducted a retrospective cohort study at a level 1 trauma centre ED of all mTBI patients 65 years old and over with an mTBI between 2010 and 2014. Main outcome was a clinically important brain injury (CIBI) reported on CT. The clinical and radiological data collection was standardised. Univariate analyses were performed to measure the predictive capacities of different age cut-offs at 70, 75 and 80 years old.

Results 104 confirmed mTBI were included; CT scan identified 32 (30.8%) CIBI. Sensitivity and specificity (95% CI) of the CCHR were 100% (89.1 to 100) and 4.2% (0.9 to 11.7) for a modified criteria of 70 years old; 100% (89.1 to 100) and 13.9% (6.9 to 24.1) for 75 years old; and 90.6% (75.0 to 98.0) and 23.6% (14.4 to 35.1) for 80 years old. Furthermore, modifying the age criteria to 75 years old showed a reduction of CT up to 25% (n=10/41) among the individuals aged 65–74 without missing CIBI.

Conclusion Adjusting the age criteria of the Canadian CT head rule to 75 years old could be safe while reducing radiation and ED resources. A future prospective study is suggested to confirm the proposed modification.

  • trauma
  • head
  • imaging
  • CT/MRI
  • geriatrics

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  • Contributors MÉ had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. NF and MÉ were responsible of design, funding and conduct of the study. NF led the analyses and wrote the manuscript. NF, MÉ and P-HC were involved in the statistical analysis and data interpretation. NF, CG, J-FP, VB and ÉF were responsible for data collection. J-LG was responsible for reviewing medical imaging. All authors reviewed and approved the manuscript.

  • Funding This study was funded by the Fondation du CHU de Québec – Université Laval.

  • Competing interests None declared.

  • Ethics approval This study was approved by the ‘Comité d'éthique du CHU de Québec’ (2016-2543).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement There are no unpublished data from this study.

  • Patient consent for publication Not required.