Canadian CT Head Injury/Trauma Rule

• The Canadian CT Head Rule is a well-validated clinical decision aid that allows physicians to safely rule out the presence of intracranial injuries that would require neurosurgical intervention without the need for CT imaging.
• The CCHR has been found to be 70% sensitive for “clinically important” brain injury in EtOH intox patients (Easter 2013).

The Canadian CT Head Rule (CCHR) was developed to help physicians determine which minor head injury patients need head CT imaging.

• The original validation trial and multiple subsequent studies (Stiell 2001, Stiell 2005, Stiell 2010) each found the CCHR’s High Risk Criteria to be 100% sensitive for injuries requiring neurosurgical intervention. It has an 87-100% sensitivity for detecting “clinically important” brain injuries that don’t require neurosurgery.
• The rule excluded patients on oral anticoagulants and anti-platelet agents, so no data is available for these patients.
• Patients with minimal head injury (i.e., no history of loss of consciousness, amnesia, and confusion) generally do not need a CT scan. For example, patients over 65 years may not need a CT scan just based on their age if they do not have the history mentioned above. When a patient fails the CCHR, use clinical judgment on whether a CT scan is necessary.
• One study found the CCHR the most consistent, validated, and effective clinical decision rule for minor head injury patients.

Points to keep in mind:

• While there is only one US validation study for the CCHR, it was 100% sensitive for clinically important injuries and injuries requiring neurosurgery.
• A retrospective study in the United Kingdom found that applying the CCHR would have actually resulted in an increase in the number of patients undergoing CT scan in that particular practice setting.
• There is debate about whether the goal should be to find all intracranial injuries or to find patient-important ones that would require neurosurgical intervention.

There are more than 8 million patients who present annually to US Emergency Departments for evaluation of head trauma. The vast majority of these patients have minor head trauma that will not require specialized or neurosurgical treatment. At the same time, rates of CT imaging of the head have more than doubled from the early 1990s through the 2000s.