From the Guidelines
Head CT scans are indicated for head injuries when there are concerning signs or symptoms that suggest possible intracranial injury, particularly in patients with a Glasgow Coma Scale (GCS) score less than 15, loss of consciousness, amnesia, persistent vomiting, age over 65, drug or alcohol intoxication, seizures, severe headache, signs of basilar skull fracture, focal neurological deficits, and dangerous mechanism of injury. The primary indications for head CT scans include:
- GCS score less than 15
- Loss of consciousness
- Amnesia about the traumatic event
- Persistent vomiting (two or more episodes)
- Age over 65 years
- Drug or alcohol intoxication
- Seizures following injury
- Severe headache
- Signs of basilar skull fracture (such as raccoon eyes, Battle's sign, hemotympanum, or CSF otorrhea/rhinorrhea)
- Focal neurological deficits
- Dangerous mechanism of injury (such as pedestrian struck by vehicle, ejection from vehicle, or fall from height greater than 3 feet or 5 stairs) Additional indications include anticoagulant use or coagulopathy, visible trauma above the clavicle, and multiple trauma 1. CT scanning is preferred over MRI in acute settings due to its speed, availability, and superior ability to detect acute hemorrhage and skull fractures. Clinical decision rules like the Canadian CT Head Rule or the New Orleans Criteria can help guide appropriate use of head CT in adults with minor head trauma 1. Some of the key points to consider when deciding to obtain a head CT include:
- The risk of missing a significant intracranial injury
- Radiation exposure concerns, particularly in children and pregnant women
- The use of clinical decision rules to guide appropriate use of head CT
- The importance of balancing the benefits and risks of head CT scans in patients with mild head trauma 1.
From the Research
Indications for Head CT in Head Injuries
The following are indications for head CT in the case of head injuries:
- Patients with a Glasgow Coma Scale (GCS) score of 14 or 15, with a skull fracture and/or neurological deficits, as they have a higher risk of intracranial hematoma requiring surgical evacuation 2
- Medium risk mild injury patients with a GCS of 15 and one or more of the following symptoms: loss of consciousness, amnesia, vomiting, or diffuse headache, especially if CT scanning is readily available 2
- Patients with minor head injury who have loss of consciousness (LOC) or post-traumatic amnesia (PTA), as they are at a higher risk of intracranial complications 3
- Patients with traumatic brain injury who have undergone an initial abnormal head CT, especially if they have a severe head injury (GCS < or = 8) or have shown neurologic deterioration 4
- Patients with suspected intracranial vascular injury, where CT angiography or venography or MR angiography or venography is the most appropriate imaging study 5
Specific Patient Groups
- Low-risk mild injury patients with a GCS of 15 and without a history of loss of consciousness, amnesia, vomiting, or diffuse headache may not require a head CT, but can be sent home with written recommendations 2
- Patients with mild or moderate traumatic brain injury may not require a routine repeat head CT, unless they show neurologic deterioration 4
- Patients with severe head injury (GCS < or = 8) may benefit from a routine repeat head CT, as results may lead to intervention without neurologic change 4
Imaging Modalities
- Noncontrast head CT is the most appropriate initial examination in patients with minor or mild acute closed head injury who require neuroimaging, as well as patients with moderate to severe acute closed head injury 5
- MRI may have a complementary role in short-term follow-up neuroimaging of acute traumatic brain injury, and is the most appropriate initial examination in subacute to chronic traumatic brain injury 5