Lumbar MRI: Contrast vs Non-Contrast
Non-contrast lumbar MRI is the standard imaging study for evaluating degenerative spine disease, disc herniation, spinal stenosis, and nerve root compression; intravenous contrast is not routinely indicated and should be reserved for specific clinical scenarios only. 1
Standard Imaging Protocol
Start with MRI lumbar spine without IV contrast for all patients with:
- Radiculopathy or clinical signs of nerve root compression 2
- Persistent symptoms after 6 weeks of conservative management who are surgical or interventional candidates 1, 3
- Suspected disc herniation or spinal stenosis 2
- Diagnostic uncertainty after adequate conservative trial 3
Non-contrast MRI reliably visualizes all critical structures including disc degeneration and herniation, thecal sac and neural elements, nerve root compression, spinal stenosis, and facet joint arthropathy. 3
When Contrast IS Required
Add intravenous contrast (with pre-contrast sequences) in these specific situations:
Post-Operative Patients
- Distinguishing recurrent/residual disc herniation from postoperative epidural fibrosis (scar tissue) is the primary indication for contrast. 1, 2
- Contrast-enhanced MRI achieves 96% accuracy in differentiating scar from disc at reoperated levels. 4
- This distinction is essential because scar tissue typically does not require surgical intervention while recurrent disc herniation may. 1
Suspected Infection or Malignancy
- Clinical suspicion for epidural abscess, discitis, or osteomyelitis 1, 2
- Suspected neoplasm involving the spine or spinal cord 1
- Red-flag symptoms suggesting inflammatory disease 3
Indeterminate Studies
- When non-contrast MRI is technically inadequate or clinically inconclusive 1, 2
- Contrast helps assess enhancement patterns that clarify ambiguous findings 1
What NOT to Do
Critical pitfalls to avoid:
- Never order MRI with contrast alone as an initial study—interpretation requires correlation with non-contrast sequences, and contrast-only imaging is inappropriate. 1, 3
- Do not add contrast for routine degenerative conditions—it provides no diagnostic value for typical disc disease, stenosis, or facet arthropathy. 1, 3
- Avoid early imaging (within 4 weeks) for uncomplicated low back pain—this increases unnecessary procedures, surgery rates, and disability claims without improving outcomes. 3
- Do not assume MRI abnormalities equal clinical disease—disc abnormalities occur in 20-28% of asymptomatic individuals, and herniation size does not predict clinical outcome. 3
Clinical Decision Algorithm
Follow this stepwise approach:
Initial presentation: Most patients with uncomplicated low back pain achieve resolution within 6 weeks with conservative therapy (NSAIDs, activity modification, physical therapy). 3
Imaging timing: Order non-contrast lumbar MRI only after 6 weeks of failed conservative management in surgical/interventional candidates. 1, 3
Contrast decision: Add contrast only if the patient has:
Appropriateness ratings: The American College of Radiology consistently rates non-contrast lumbar MRI as "usually appropriate" (8-9/10) for nerve impingement evaluation, while contrast receives lower ratings (4-6/10) except in the specific scenarios above. 2
Alternative Modalities
When MRI is contraindicated:
- CT without contrast is acceptable for patients with pacemakers or certain implants 3
- CT performs comparably to MRI for detecting clinically significant spinal stenosis but has lower sensitivity (~55%) for disc herniation 3
- CT myelography can assess canal patency and neural foramina in patients with MRI-incompatible hardware 1
Pediatric Considerations
In children with back pain and red-flag features: