Does she need an MRI scan?

MRI Scan Decision-Making in Back Pain

MRI is indicated for back pain when there are neurological deficits, suspected structural abnormalities, or when conservative treatment fails, but is not recommended for routine evaluation of non-specific back pain.

When MRI is Indicated

Red Flag Symptoms Requiring MRI

• Neurological deficits (motor weakness, sensory changes, abnormal reflexes)
• Signs of cauda equina syndrome (bladder/bowel dysfunction)
• Suspected spinal infection or malignancy
• History of trauma with suspected fracture
• Progressive or severe symptoms despite conservative treatment

Clinical Scenarios Supporting MRI Use

1. Suspected structural abnormalities:

   • MRI without contrast provides superior assessment of soft tissue and neural structures, essential for diagnosing spine fractures 1
   • MRI excels at identifying systemic disease as a cause of back pain 2

2. Persistent symptoms:

   • When conservative care fails, imaging may be undertaken with consideration of its risks 2
   • For chronic back pain (>6 weeks) not responding to treatment

3. Surgical planning:

   • MRI has an acknowledged role in planning surgical management for radiculopathy and spinal stenosis 3

When MRI is NOT Indicated

Non-specific Back Pain

• National guidelines discourage MRI use in non-specific low back pain 3
• There is no role for imaging in the initial evaluation of patients with back pain in the absence of signs or symptoms of systemic disease 2

Risks of Unnecessary MRI

• Labeling the patient with a degenerative disease diagnosis
• Cost concerns
• Potentially provoking unwarranted interventions 2
• Poor correlation between imaging findings and clinical presentation 2

Important Considerations

Diagnostic Limitations

• Anatomical abnormalities are common in the spine and may not necessarily translate into clinical symptoms 3
• The diagnostic accuracy of most lumbar anatomic impairments related to symptoms of low back pain is low or unknown 4
• Psychosocial factors predict functional disability due to disc herniation better than imaging 2

Clinical Correlation

• Only when an imaging finding is concordant with the patient's pain pattern or neurologic deficit can causation be considered 2
• MRI findings must be related to data from clinical examinations to provide meaningful judgments 4

Special Populations

Trauma Patients

• For suspected spine trauma, the American College of Radiology recommends beginning with radiography if the patient has no neurologic deficits, and considering immediate CT in emergency settings 1
• If a fracture is confirmed or strongly suspected, proceed to MRI without contrast to assess fracture acuity, posterior ligamentous complex integrity, and soft tissue injuries 1

Pregnant Patients

• MRI without contrast is the initial imaging test for suspected stress fractures in the pelvis of a pregnant patient 5

Conclusion

MRI is a powerful diagnostic tool for back pain when used appropriately. It should be reserved for cases with red flag symptoms, neurological deficits, or when conservative treatment fails. For non-specific back pain without these features, MRI is not recommended as initial evaluation.