From the Guidelines
A head CT scan is recommended for patients with head injuries who have concerning symptoms or risk factors, as indicated by clinical decision rules such as the Canadian CT Head Rule or the New Orleans Criteria, which prioritize sensitivity over specificity to minimize the risk of missing significant intracranial injuries. These clinical decision rules consider factors such as a Glasgow Coma Scale (GCS) score less than 15, suspected skull fracture, seizures, focal neurological deficits, persistent vomiting, age over 65 years, use of anticoagulants or history of bleeding disorders, and dangerous mechanism of injury.
Some key criteria from the Canadian CT Head Rule include:
- Failure to reach a GCS score of 15 within 2 hours of injury
- Suspected open skull fracture
- Sign of basal skull fracture
- Vomiting more than once
- Age greater than 64 years
The New Orleans Criteria consider:
- Headache
- Vomiting
- Age greater than 60 years
- Drug or alcohol intoxication
- Deficits in short-term memory
- Physical evidence of trauma above the clavicle
- Post-traumatic seizure
According to the most recent and highest quality study 1, the Canadian CT Head Rule and the New Orleans Criteria are both effective in identifying patients who require neurosurgical intervention, with the Canadian CT Head Rule being more specific but less sensitive than the New Orleans Criteria.
The American College of Emergency Physicians (ACEP) 2008 Clinical Policy also provides guidelines for head CT scans in patients with mild head trauma, recommending a noncontrast head CT in patients with loss of consciousness (LOC) or post-traumatic amnesia (PTA) if one or more of the following are present: headache, vomiting, >60 years of age, drug or alcohol intoxication, deficits in short-term memory, physical evidence of trauma above the clavicle, post-traumatic seizure, GCS score <15, focal neurologic deficit, or coagulopathy 1.
In patients with no LOC or PTA, a noncontrast head CT should be considered if there is a focal neurologic deficit, vomiting, severe headache, 65 years of age, physical signs of a basilar skull fracture, GCS score <15, coagulopathy, or a dangerous mechanism of injury.
It is essential to note that these guidelines are intended for patients who are 16 years of age, and separate considerations apply to the pediatric population. The use of clinical decision rules and guidelines can help minimize unnecessary CT scans while ensuring that patients with significant intracranial injuries receive timely and appropriate care.
From the Research
Criteria for Head Injury Requiring CT Scan
The criteria for head injury requiring a CT scan can be determined based on several factors, including:
- Glasgow Coma Scale (GCS) score: A GCS score of 13-15 is considered mild, while a score of 3-12 is considered moderate to severe 2, 3, 4, 5, 6
- Loss of consciousness (LOC): Patients with LOC are at higher risk of intracranial complications and may require a CT scan 2, 3
- Post-traumatic amnesia (PTA): Patients with PTA are also at higher risk of intracranial complications and may require a CT scan 3
- Focal neurological deficit: Patients with focal neurological deficits, such as weakness or numbness, may require a CT scan to rule out intracranial injury 2
- Antiplatelet and anticoagulant drugs: Patients on these medications may be at higher risk of bleeding and may require a CT scan 5
- Age: Older patients may be at higher risk of intracranial complications and may require a CT scan 6
Specific Criteria
Some specific criteria for head injury requiring a CT scan include:
- GCS score of 13-15 with LOC or PTA 2, 3
- GCS score of 3-12 with or without LOC or PTA 4, 6
- Focal neurological deficit, regardless of GCS score 2
- Patients on antiplatelet or anticoagulant drugs with a GCS score of 15 5
- Patients with a history of skull fracture or other significant head injury 2, 6
CT Scan Findings
CT scan findings can include: