spine MRI (musculoskeletal imaging in primary care)

Last reviewed 01/2018

Spine MRI

• malignancy, infection, fracture, acute disc prolapse with motor weakness or cauda equina syndrome, inflammatory disorders such as ankylosing spondylitis
  
  
• routine referral for MRI spine is indicated after 6-12 weeks of genuine radiculopathy with no improvement on conservative therapy in the context where referral for surgery is considered appropriate and the patient is willing to consider surgery. Expedited referral is for patients with acute and severe radiculopathy or low back pain who lie within high risk groups or exhibit red flags
  
  
• spinal TB
  • can present with relatively innocuous initial symptoms - often only low back pain - and may progress to paralysis
  • suspected spinal TB necessitates expedited MRI referral in those higher-risk patients who may have low-grade fever, lymphocytosis, raised plasma viscosity and anaemia. The presence of gait or sphincter disturbance and saddle anaesthesia may be subtle and raise the possibility of cauda equina syndrome, which warrants same-day specialist referral as per local policy
    
    
• patients with persistent low back pain in the absence of radiculopathy, red flags or altered biomarkers do not usually require any imaging whether MRI or x-ray. Where osteoporotic vertebral wedge fracture is suspected and ruled out with x-ray, MRI is indicated only within the context of a referral for spinal fusion for persistent or recurrent pain between 6 weeks' and 12 months' duration
  
  
• many chronic spinal pain patients improve with aggressive active rehabilitation programmes and for those that don't, imaging tests still may not be necessary. The decision to refer for imaging should include an evaluation of the patient's quality of life, psychological distress, suitability and self-inclusion for surgery

Referral for MRI spine requiring lower threshold in high-risk groups

• <20 or >55 years
• osteoporosis
• alcoholism
• HIV
• drug abuse
• steroid therapy
• adolescent athletic injury
• malignancy (suspected or diagnosed)

Clinical red flags for expedited spinal MRI

• sphincter or gait disturbance
• saddle anaesthesia
• motor loss
• elevated plasma viscosity
• weight loss, fever and other systemic symptoms
• asians with history of recent travel to subcontinent
• TB contact
• structural deformity
• non-mechanical back pain (no relief with bed rest)
• thoracic pain

Expedited referral for MRI should not delay referral for specialist opinion, which can be performed at the same time.

Absolute contraindications to MRI

• pacemaker or cardiac defibrillator
• cochlear implant
• neurostimulator
• orbital or spinal metallic foreign body
• untested intracranial aneurysm clips
• infusion pumps
• implanted drug infusion ports

Reference:

• 1) Arthritis Research UK (Summer 2013). Hands on - Musculoskeletal imaging for GPs.