criteria for CT head scan following a head injury

Last edited 05/2023 and last reviewed 05/2023

Current primary investigation of choice for the detection of acute clinically important brain injuries is CT imaging of the head.

For adults who have sustained a head injury and have any of the following risk factors, perform a CT head scan within 1 hour of the risk factor being identified:

With respect to CT scan for an adult with a head injury:

• adult patients who have sustained a head injury and present with any one of the risk factors outlined should have CT scanning of the head requested immediately
  • risk factors suggesting need for immediate CT scan
    • GCS less than 13 on initial assessment in the emergency department
    • GCS less than 15 at 2 hours after the injury on assessment in the emergency department
    • suspected open or depressed skull fracture
    • any sign of basal skull fracture (haemotympanum, 'panda' eyes, cerebrospinal fluid leakage from the ear or nose, Battle's sign)
    • post-traumatic seizure
    • focal neurological deficit
    • more than one episode of vomiting
      
      
  • for people 16 and over who have had some loss of consciousness or amnesia since the injury, do a CT head scan within 8 hours of the head injury, or within the hour in someone presenting more than 8 hours after the injury, if they have any of these risk factors:
    • age 65 or over
    • any current bleeding or clotting disorders
    • dangerous mechanism of injury (a pedestrian or cyclist struck by a motor vehicle, an occupant ejected from a motor vehicle or a fall from a height of more than 1 m or 5 stairs)
    • more than 30 minutes' retrograde amnesia of events immediately before the head injury
      
      
• CT should also be requested immediately in patients with any of the risk factors outlined below, provided they have experienced some loss of consciousness or amnesia since the injury
  • risk factors for immediate CT scan if patient has experienced some loss of consciousness
    • age 65 years or older
    • coagulopathy (history of bleeding, clotting disorder, current treatment with warfarin)
    • dangerous mechanism of injury (a pedestrian or cyclist struck by a motor vehicle, an occupant ejected from a motor vehicle or a fall from a height of greater than 1 m or five stairs)
• a provisional written radiology report should be made available within 1 hour of the scan being performed

For patients (adults and children) who have sustained a head injury with no other indications for a CT head scan and who are having anticoagulant treatment (1)

• perform a CT head scan within 8 hours of the injury or
  • within the hour if they present more than 8 hours after the injury
  • a provisional written radiology report should be made available within 1 hour of the scan being performed.

With respect to CT scan for a child (under 16 years of age) with a head injury:

• for people under 16 who have sustained a head injury, do a CT head scan within 1 hour of any of these risk factors being identified:
  • suspicion of non-accidental injury
  • post-traumatic seizure
  • on initial emergency department assessment, a GCS score of less than 14 or, for babies under 1 year, a GCS score (paediatric) of less than 15
  • at 2 hours after the injury, a GCS score of less than 15
  • suspected open or depressed skull fracture, or tense fontanelle
  • any sign of basal skull fracture (haemotympanum, 'panda' eyes, cerebrospinal fluid leakage from the ear or nose, Battle's sign)
  • focal neurological deficit
  • for babies under 1 year, a bruise, swelling or laceration of more than 5 cm on the head
    
    
• for people under 16 who have sustained a head injury and have more than 1 of these risk factors, do a CT head scan within 1 hour of the risk factors being identified:
  • loss of consciousness lasting more than 5 minutes (witnessed)
  • abnormal drowsiness
  • 3 or more discrete episodes of vomiting
  • dangerous mechanism of injury (high-speed road traffic accident as a pedestrian, cyclist or vehicle occupant, fall from a height of more than 3 m, high-speed injury from a projectile or other object)
  • amnesia (anterograde or retrograde) lasting more than 5 minutes (it will not be possible to assess amnesia in children who are preverbal and is unlikely to be possible in children under 5)
  • any current bleeding or clotting disorder
    
    
  • observe people under 16 who have sustained a head injury but have only 1 of the risk factor for a minimum of 4 hours in hospital. If, during observation, any of the following risk factors are identified, do a CT head scan within 1 hour:
    • a GCS score of less than 15
    • further vomiting
    • a further episode of abnormal drowsiness. If none of these risk factors occur during observation, use clinical judgement to determine whether a longer period of observation is needed

Reference:

1. NICE (May 2023). Triage, assessment, investigation and early management of head injury in infants, children and adults