Is contrast needed to identify a Morton's neuroma (Morton's neuroma) on imaging studies like Magnetic Resonance Imaging (MRI)?

Contrast is NOT Required for Morton's Neuroma Diagnosis

You do not need contrast to identify a Morton's neuroma on MRI—non-contrast MRI is adequate and recommended as the primary imaging approach, with ultrasound being equally effective and often preferred. 1, 2, 3

Recommended Imaging Algorithm

First-Line Imaging

• Start with radiographs to exclude other causes of webspace pain including osteoarthritis, Freiberg's infraction, and stress fractures (though radiographs are insensitive for Morton's neuroma itself) 2, 3

Advanced Imaging After Negative Radiographs

• Ultrasound (90% sensitivity) is the preferred initial advanced imaging modality according to the American College of Radiology 1, 2, 3

  • Allows dynamic examination and direct clinical correlation during the procedure 1, 3
  • Particularly effective for detecting small neuromas (<5 mm) 4
  • One study demonstrated 96% sensitivity, superior to MRI for small lesions 4

• MRI without contrast (93% sensitivity) is an excellent alternative when ultrasound is equivocal or unavailable 1, 2, 3

  • T1-weighted spin-echo sequences alone are adequate for diagnosis 5
  • Non-contrast T1-weighted images provide superior contrast-to-noise ratios compared to other sequences 5

When Contrast May Be Considered

While contrast is not necessary for routine diagnosis, contrast-enhanced MRI with fat suppression can improve lesion conspicuity in diagnostically challenging cases 6. However, this represents an exception rather than standard practice:

• A 1993 study showed that contrast enhancement combined with fat suppression provided the clearest depiction when conventional sequences failed 6
• Reserve contrast-enhanced imaging for equivocal cases where non-contrast MRI is inconclusive 5

Important Clinical Caveats

• False negatives occur with both modalities, particularly with older equipment or less experienced operators 7, 8
• Ultrasound is operator-dependent and subject to interoperator variability 8
• MRI is particularly valuable for correct localization when clinical examination cannot identify the specific intermetatarsal space (occurs in approximately 40% of cases) 5
• The third intermetatarsal space is the most common location 8

Practical Recommendation

Begin with ultrasound for suspected Morton's neuroma given its high sensitivity, lower cost, dynamic capability, and ability to correlate findings with clinical symptoms in real-time 1, 2, 3. If ultrasound is negative or equivocal but clinical suspicion remains high, proceed to non-contrast MRI with T1-weighted sequences 5. Only add contrast if both non-contrast MRI and ultrasound are inconclusive 6, 5.