Clinical guidance for MRI referral

MRI of the cervical spine

Cervical spine trauma

MBS item description

Referral by a medical practitioner (excluding a specialist or consultant physician) for a scan of spine for a patient 16 years or older for suspected cervical spine trauma (R) (K)

Key information

  • There is a lack of evidence that MRI has led to improved health outcomes for patients with cervical trauma.
  • CT is superior to MRI and X-ray at identifying cervical spine fractures – there is strong evidence to suggest fractures may be missed with cervical X-rays.
  • MRI is not reliable for identifying cervical spine fracture.
  • MRI is superior at identifying soft tissue injuries, such as spinal cord and ligamentous injury; however, it is unclear if all findings identified by MRI are clinically significant.
  • A negative CT scan, when reviewed by an appropriate radiologist, is sufficient to cease spinal precautions.

Explanation
Level 2 - The recommendation is reasonably justifiable by available scientific evidence and strongly supported by expert opinion. This recommendation is usually supported by Class II data or a preponderance of Class III evidence.

Class II: clinical studies in which data were collected prospectively or retrospective analyses based on clearly reliable data (20 references) Class III: studies based on retrospectively collected data (32 references)

Recommendation
Cervical spine imaging is not indicated in awake, alert patients with trauma without neurological deficit or distracting† injury who have no neck pain or tenderness with full range of motion of the cervical spine

Explanation
B - A body of evidence including studies rated as 2++ directly applicable to the target population and demonstrating overall consistency of results

or Extrapolated evidence from studies rated as 1++ or 1+ 1++ High quality meta-analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias 1+ Well-conducted meta-analyses, systematic reviews of RCTs, or RCTs with a low risk of bias

Recommendation
If a cervical spine fracture is suspected, imaging with CT or X-ray is indicated

Explanation
C – A body of evidence including studies rated as 2+ directly applicable to the target population and demonstrating overall consistency of results

or Extrapolated evidence from studies rated as 2++ 2+ Well-conducted case–control or cohort studies with a low risk of confounding, bias or chance and a moderate probability that the relationship is causal 2++ High-quality systematic reviews of case–control

or cohort studies or High quality case–control or cohort studies with a very low risk of confounding, bias, or chance and a high probability that the relationship is causal

Recommendation
MRI has a role where other imaging is contraindicated/inconclusive or where clinical or imaging findings suggest ligamentous injury, spinal cord injury and/or arterial injury

The major concern with cervical spine trauma is fracture. While injury to the cervical spine is common after trauma (such as motor vehicle accidents and falls), fractures of the cervical spine are uncommon. Because of the serious medical, psychological and financial consequences of missed fractures, the use of imaging of the cervical spine to exclude fracture is a routine part of the evaluation of the trauma patient.37,40

Fractures of the cervical spine may not be clinically obvious. Patients may be neurologically intact initially but, if not treated appropriately and promptly, may progress to severe neurological compromise. Delayed onset of paralysis occurs in as many as 15% of missed fractures, and death owing to unidentified cervical spine fracture is possible.37

Soft tissue injury (e.g. whiplash injury) may occur following sudden or excessive hyperextension, hyperflexion or rotation of the neck. Whiplash injury causes neck pain and other symptoms, which may be severe and persist for more than 6 months. Signs of whiplash injury include neck pain and stiffness extending to the shoulders and thoracic spine, persistent headache, dizziness, upper-limb paraesthesia and psychological and emotional symptoms.41

Assessment of the patient with suspected cervical trauma

In the emergency room after blunt trauma to the neck, triage should be based on the Canadian C-spine rule or the NEXUS criteria to rule out the need for further imaging.31,33

Table 2.10 NEXUS criteria

Table 2.10

NEXUS criteria

In contrast, in ambulatory primary care, triage is usually based on history and physical examination alone.33 In some situations, GPs may elect to use the Canadian C-spine rule and NEXUS criteria.

Physical examination

Look for signs of muscular spasm, point tenderness and neurological problems in the upper or lower limbs.42

It is also safe to assess for range of neck movements if the person:

  • does not have midline cervical tenderness (as this suggests a fracture or dislocation) or other serious injuries
  • was involved in a simple rear-end collision
  • is in a sitting position in the waiting room
  • can walk about at any time after the injury
  • has delayed onset of neck pain.42

Patients do not require cervical spine imaging if they are awake, alert, without neurological deficit and have no neck pain or tenderness with full range of motion of the cervical spine.37

There is no scientifically admissible evidence to support use of routine MRI as a screening tool in cervical trauma.33

X-ray

There is strong evidence to suggest that use of routine cervical spine radiographs alone (compared to CT scans) may miss important injuries in the evaluation of patients with traumatic, high-risk neck injuries in emergency situations, and that CT scan should be used instead.31

Even when using a three-view X-ray series, there is evidence of missed injuries in up to 57% of high-risk patients and in 7–35% of patients overall. Additionally, the three-view series can be difficult to obtain, with reports of inadequate visualisation in 50–80% of initial and 25% of repeat radiographs.43

However, flexion–extension X-rays are still an important tool in the assessment of patients with cervical spine injuries, and may be useful in excluding dynamic instability, particularly in those patients who have sustained a significant ligamentous injury and no fracture.

CT

CT scans have better validity than radiographs in assessing high-risk and/or multi-injured blunt trauma neck patients.31 There is evidence that CT should be the preferred imaging modality, replacing plain films in the initial evaluation of suspected cervical spine injuries.43

CT is superior to MRI in identifying bony injuries such as osseous fracture, vertebral subluxation/dislocation and locked facets.37

Modern CT alone is sufficient to detect unstable cervical spine injuries in trauma patients. Adjuvant imaging is unnecessary when the CT scan is negative for acute injury.44

MRI

MRI is not suitable for detecting fracture.

MRI is superior at identifying soft tissue injuries, such as spinal cord injury and ligamentous injury.37 MRI is preferred for evaluating possible ligamentous injuries in acute cervical spine trauma and possible spinal cord injury.39

Note that role of MRI in evaluating ligamentous and membranous abnormalities in patients with whiplash-associated disorders is controversial.45 There is evidence that MRI may not demonstrate soft tissue lesion in acute whiplash injury. MRI has been shown to reveal changes in the ligaments of the upper cervical spine in late stage whiplash injury; however, these findings may not be clinically significant, nor do they assist with treatment planning.31,45

MRI should be limited to patients in whom other studies are contraindicated or if the imaging fails to adequately clear the patient for suspected fracture.46

MRI is not required to clear the spine (rule out fracture) if a radiologist has reported a negative CT.44

MRI is able to detect abnormalities not present with other imaging.47 However, many findings will not be clinically significant.48

Despite its high sensitivity, in particular for soft tissue injury, MRI suffers from poor specificity in terms of determining clinically relevant information such as instability. It is thus rarely appropriate as a means of achieving cervical spine clearance.

The risk–benefit ratio of obtaining MRI in addition to CT is not clear and its use must be individualised.37

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