Use CT scan to identify intracranial injury during the acute period (first 48 hours of injury).
When to perform CT scan
- Assess within 15 minutes of emergency department presentation if suspicion is high.
- Use Canadian CT Head Rule (for brain CT) and Canadian C-Spine Rule or NEXUS (for CT C-spine) to support decision-making.
- If performing a CT brain scan, also consider the need for a CT of the C-spine.
- CT is not routine for mild head injury – only if high-risk features are present.
- Order CT brain scan (on site or via urgent transfer) if any high-risk features are present (see table below).
High-risk features to consider a CT scan
Drag the table right to view more columns or turn your phone to landscape
| Factor | High-risk features to consider CT scan |
|---|---|
GCS < 15 at 2 hours after injury on assessment in emergency department GCS below 15 as a critical factor for CT scanning Persisting post-traumatic amnesia, A-WPTAS (PDF) (PDF 603.5 KB) (PDF < 18/18 at 4hrs post injury Change in behaviour, including abnormal drowsiness, increasing agitation, restlessness or combativeness | |
| Neurological deficits and deterioration | A new focal neurological deficit, e.g. hemiparesis or altered consciousness |
| Headache | Persistent severe headache |
| Skull fracture suspicion | Clinical suspicion of skull fracture Open, depressed or base of skull fracture: look for signs of base of skull fracture, e.g. raccoon or panda eyes, Battle’s sign, cerebrospinal fluid leak |
| Vomiting | 2 or more episodes of vomiting |
| Age | Over 65 years are at a higher risk Over 50 years for vulnerable populations, e.g. Aboriginal people or multiple comorbidities |
| Seizure and loss of consciousness | Post-traumatic seizures and loss of consciousness > 1 minute |
| Coagulopathy or bleeding disorders | People with known coagulopathies (clotting disorders or chronic liver disease) or on anticoagulants, are at high risk for brain haemorrhage or worsening trauma |
| Mechanism | Dangerous mechanisms of injury, such as falls from a height or road-related trauma, may suggest a need for urgent imaging Use the Canadian CT Head Rule to assess risk factors |
The Canadian CT Head Rule helps clinicians identify which patients with a mild traumatic brain injury need a CT scan.
Consider abuse, neglect and domestic violence for clinical features that suggest maltreatment.
Imaging to avoid
Avoid using these imaging techniques for mild traumatic brain injury:
- Skull x-rays
- Single photon emission computed tomography (SPECT)
- Quantitative electroencephalogram (EEG)
CT scan
Depending on your healthcare service, you may or may not have access to a CT scanner. Refer to the below processes, depending on whether CT scan is available or not.
When CT scan is available
When determining which patients with a mild traumatic head injury need a CT scan, focus on clinical assessment, identifying risk factors and prompt decision-making.
- Risk factor identification: clinical assessment of high-risk features.
- Timing of assessment: early assessment, i.e. within 15 minutes of presentation to emergency department (ED), when there is a high index of suspicion of injury and high-risk features.
- Conditional use of CT scans: CT scanning should not be performed routinely for mild head injuries; only when clear risk factors are present.
- Re-examination and clinical judgement: patients in the ED or admitted to the ward will need ongoing observation and re-evaluation to capture changes in neurological status, e.g. deterioration in GCS and subsequent need for CT scan.
When CT scan is not available
- Escalate early: use coordination services such as vCare, the Aeromedical Control Centre or NSW Ambulance, when needed.
- Identify high-risk patients: patients who are at increased risk of structural brain injury that may require neurosurgical consultation or intervention.
- Use the Canadian CT Head Rule: this provides decision-making support to assess the need for CT and guides transfer decisions. Make decisions on a case-by-case basis.
- Transfer decision: make an early and clear decision if transfer is required.
- Consult early: seek timely consultation with neurosurgical team and transfer coordination services, if required (preferably in one call).
- Transfer high-risk patients to a facility with a CT scanner and/or neurosurgical capabilities: for further investigation or treatment; and to diagnose, rule out or manage neurosurgically significant lesions, e.g. intracranial haemorrhage.
- Consider the patient’s social and family circumstances: look at the distance from home, community or Country when considering a transfer.
- Patients on anticoagulants: use a lower threshold for transfer for patients on non-vitamin K antagonist oral anticoagulants (NOACs), warfarin, antiplatelet therapy; or with clotting disorders, initiate reversal if intracranial haemorrhage is confirmed.
- Communicate critical information: use ISBAR (PDF 141.0 KB) to discuss clinical condition, time since injury (less than 48 hours) and logistical factors, e.g. distance to services, likelihood of intervention and transport availability.
- Monitor borderline cases: this includes patients who are not transferred with serial GCS over 24 hours.
- Avoid routine neuroimaging: this is not required for all patients to diagnose mild traumatic brain injury or concussion.
Use of biomarkers for CT scan screening
Although evidence for their use in the assessment of mild traumatic brain injury is promising, there is still uncertainty about their role in routine clinical practice.
The necessary laboratory and diagnostic infrastructure is also not yet widely available across NSW Health to support consistent implementation in everyday practice.
Further imaging
Consider repeat imaging if signs of clinical deterioration are present, despite an initially normal CT scan. This also applies to high-risk patients on anticoagulants who may require close monitoring or additional imaging. Any repeat scanning should be led by a senior clinician.
Senior clinicians may order a magnetic resonance imaging (MRI) scan if:
- CT findings are inconclusive
- possible pathology is missed by CT in patients with ongoing and concerning clinical presentation.
MRI may identify more subtle changes in brain pathology.