Traumatic brain injury

Dr Hamish Smith and Dr Henry Knipe et al.

Traumatic brain injuries (TBI) are common and come with a large cost to both society and the individual. Imaging, particularly CT, plays a key role in accurate diagnosis, classification and follow-up. 

They can be broadly divided into closed and penetrating head injuries 4:

The remainder of this article focuses on closed head injury. 

Traumatic brain injuries are more common in young patients, and men account for the majority (75%) of cases 4. Although sport is a common cause of relatively mild repeated head injury potentially eventually leading to chronic traumatic encephalopathy, more severe injuries are most often due to motor vehicle accidents and assault. 

Patients typically present with a combination of reduced Glasgow Coma Scale (GCS), nausea/vomiting and/or amnesia 3. The severity of the injury can be assessed with GCS 4:

  • mild TBI: GCS 14-15
  • moderate TBI: GCS 9-13
  • severe TBI: GCS 3-8

This scale has limitations as there are other causes for reduced GCS in trauma (alcohol, drugs, seizure, etc). 

In the acute setting patients can present with primary brain damage 4

Secondary brain damage can also occur and manifests as 4:

Long-term sequelae of head trauma include:

Severe mass effect can result in:

Other traumatic injuries are common:

CT is the workhorse of imaging in TBI, especially in the acute setting, and is able to identify the majority of injuries at the time of presentation. It is common for multiple injuries to be present simultaneously, such as the combination of cerebral contusions and traumatic subarachnoid, subdural and extradural hemorrhage as well as skull fractures and facial fractures – these are discussed separately. 

CT can also be used to formally classify the degree of injury using a formal scale (e.g. Marshall classification or Rotterdam CT score).

MRI has a supplementary role, especially in the evaluation of patients whose clinical condition do not match the CT findings (this can often occur in DAI) 1,2. Please see the relevant articles for imaging findings. ​

Large hematomas with significant mass effect require urgent neurosurgical evacuation. Hydrocephalus can develop and urgent ventricular drainage may be required. Intracranial pressure (ICP) monitor insertion is a common procedure used to help in the assessment of severe TBI. 

Ongoing follow-up with CT is often required. In patients with diffuse injuries ~15% will develop new lesions, and ~35% (range 25-45%) of cerebral contusions will increase in size with progression thought to typically occur 6-9 hours after injury 4. ​

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Article information

rID: 46289
Synonyms or Alternate Spellings:
  • Closed head injury
  • Traumatic brain injuries
  • TBI
  • Penetrating head injury
  • Penetrating brain injury (PBI)
  • Closed brain injury (CBI)

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Cases and figures

  • Case 1
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  • Case 2
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  • Case 3: gun shot injury
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  • Case 4: with ICP monitor
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  • Case 5: diffuse axonal injury
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  • Case 6: penetrating head injury (stabbing)
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