Indications for Imaging

CT scanning is the preferred method of imaging if available and should be performed early in the severe to moderate TBI group. Except for an uncomplicated minor head injury, ideally all patients with a significant head injury should have a CT scan. If it appears that the patient will require transfer to an MTS, the decision as to whether to conduct a CT prior to retrieval must be considered. Any CT scans that are performed prior to transfer to the MTS must be sent with the patient. In virtually all situations the CT scan will be performed upon admission to the MTS, and expedient transfer of the patient to MTS must be facilitated. Any critical trauma patient must be very carefully monitored and attended while in the CT scanner.
Definite indications for CT scanning are:4
  • GCS under 9 after resuscitation.
  • Neurological deterioration such as two or more points on the GCS; hemiparesis.
  • Drowsiness or confusion (GCS 9–13 persisting > 2 hours).
  •  Persistent headache, vomiting.
  • Focal neurological signs (pupil inequality, change in reactivity such as dilated pupils and unreactive on one side, hemiparesis involving the limbs on one side).
  • Skull fracture – known or suspected.
  • Penetrating injury – known or suspected.
  • Age over 50 years following trauma d/t increased risk of injury in the elderly.
  • Post-operative assessment such as emergency burr hole evacuation.
  • Seizures.
  • Other risk factors such as chronic liver disease or the use of anticoagulants.


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All major trauma patients suspected of having a cervical spine injury should be evaluated using the NEXUS criteria. NEXUS provides a decision tool for use in the assessment of the conscious patient to indicate those at very low risk of c spine injury following blunt trauma who may not need radiographic imaging.
Patients are considered to be at extremely low risk of cervical spine injury if ALL of the following criteria are fulfilled:
  • No midline cervical spine tenderness.
  • No focal neurological deficit.
  • No evidence of intoxication.
  • No painful distracting injury.
  • No altered mental status (including therapeutic or illicit drug effects)
If all of the above criteria are satisfied, clinical examination may then proceed. If there is no evidence of any bruising, deformity or tenderness on examination, and if a full range of active movement can be performed without pain (including 45degree rotation to left and right), the cervical spine can be cleared without radiographic imaging and the cervical collar be removed.
Should the patient exhibit any of the criteria, however, clinical examination is unreliable and radiographic assessment of the cervical spine is advised.
Plain X‐rays may provide initial information on spinal injury, however, are not used to clear the trauma patient of injury. The patient should be cared for as a possible cervical vertebral injury.
A CT scan should be undertaken if the NEXUS criteria for cervical spine clearance has not been met, or the patient is unconscious. Where facilities do not have CT imaging available, then consultation with ARV and the MTS regarding retrieval and transfer should take place. X-ray imaging of the cervical spine is not suitable to clear the neck of the trauma patient. It may be appropriate to delay exhaustive imaging investigations if they are not going to alter management. Definitive imaging may be performed at the receiving specialist unit.
If staff are trained in its application, a Philadelphia collar should be applied within 6 hours so as to prevent any pressure injuries and aid in patient comfort.

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A mobile chest x-ray should be performed in the resuscitation bay at the earliest opportunity. Findings on a chest radiograph include pneumothorax (which is difficult to see on a supine image), pneumo-mediastinum, airspace opacities (resulting from pulmonary contusion), and haemothorax.5 Repeat X-rays should be undertaken after each intervention such as insertion of a chest tube / intubation. Mechanical ventilation predisposes the patient to barotrauma and pneumothorax.


Conventional echocardiography has long been used to image the heart, the pericardial space, and the ascending aorta. Because ultrasonography is unique in being portable, rapid, and noninvasive, it is particularly suited to the trauma setting and offers immediate feedback that may be incorporated into the management plan for the patient. Ultrasonography is operator dependent and may cause some aortic injuries to be missed.

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Patients with severe trauma are often difficult to scan with CT because of resuscitative equipment. CT is an excellent modality, but patients are required to receive contrast agents and be transported from the protected resuscitation area to the radiology suite. Therefore, CT scanning is difficult to perform in hemodynamically unstable patients.
In the stable patient, further CT imaging can be obtained to identify aortic injuries (CT Angiogram). CT scans also demonstrate injuries to the lung, pleura, mediastinum, and chest wall better than plain radiographs do. Many serious thoracic injuries may be overlooked on initial chest radiographs; these include tracheobronchial tears, diaphragmatic rupture, esophageal tears, thoracic spine injuries, chest wall and seat-belt injuries, lung contusion, cardiac injuries, pneumothorax, haemothorax, and chest tube complications.


MRI in the acute trauma setting is predominantly used to evaluate spinal cord, disco-ligamentous injuries and epidural hematoma. It is also being more widely utilised for prognostication of traumatic brain injuries. MRI with breath-hold acquisition permits good visualization of diaphragmatic abnormalities, but this technique cannot be performed in emergency situations. Nevertheless, the indication is carefully weighed in patients with multiple trauma because of monitoring difficulties during the examination, which may be long. MRI is also expensive and is not universally available in emergency departments. MRI safety of the patient, staff and monitoring devices are also major consideration prior to putting patients through MRI scanners.

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In the trauma patient with abdominal pain, a FAST should be performed early in the primary survey. This is a non-invasive procedure, is quick to perform and can be completed in the ED.


  • Used to identify free fluid in the peritoneal cavity.
  • Sensitivity approaching 96% in detecting >800mls blood.
  • Involves directing the ultrasound probe in four main regions.
  • Subxiphoid: to determine fluid in the pericardial space and to assess filling and contractility.
  • Right upper quadrant: Liver, kidney, diaphragm (including Morrison’s pouch)
  • Left upper quadrant: Diaphragm, spleen, kidney.
  • Suprapubic view: Bladder.
Positive results from a FAST scan warrant further investigation and management in accordance with the patients’ clinical status.


AP Pelvis should be completed in the ED to confirm the presence of a pelvic fracture.
If the patient has a pelvic binder in place then an AP pelvic radiograph will be performed with the binder on and off. This is because pelvic fractures can be missed if they are completely reduced by the binder. Pelvic binder should only be released at a site where the triggering of further bleeding can be managed (e.g. MTS).
There is no role for performing abdominal x ray besides assessment of ingested foreign bodies and penetrating trauma with the foreign body or weapon in situ.

CT abdomen /pelvis

Must be performed with intravenous contrast and oral contrast is no longer used.
  • Is the modality of choice in assessing hollow and solid visceral injuries, vascular injuries, spinal and bony pelvic injuries, haemoperitoneum and pneumoperitoneum & allows specific injuries to be graded.
  • In the haemodynamically stable patient with suspected intra-abdominal injury the key decision is whether the patient requires CT scanning or a period of observation. It is the diagnostic modality of choice in the stable patient.
  • Contrast extravasation found on CT is a sign of active bleeding and may require interventional radiology services if available.It is also a strong predictor of failure of non-operative management.
  • Hollow viscus, diaphragmatic & pancreatic injuries are frequently missed on initial scanning. Isolated intraperitoneal fluid findings on CT should raise a high suspicion of hollow organ injury.