What are the guidelines for shoulder imaging in the context of chronic injury?

Guidelines for Shoulder Imaging in Chronic Injury

For chronic shoulder injuries, radiography should be the initial imaging modality, followed by MRI without contrast if radiographs are negative and symptoms persist. 1, 2

Initial Imaging Approach

• Plain radiographs are the recommended first-line imaging modality for all shoulder pain, including chronic injuries 2

  • Standard views should include:
    • Anteroposterior (AP) view
    • Grashey view (true AP)
    • Axillary view
    • Scapular Y view

• Important note: Normal radiographs do not rule out soft tissue pathology such as rotator cuff tears, labral tears, or bursitis 2

Advanced Imaging Options

When radiographs are negative or insufficient for diagnosis, advanced imaging should be selected based on suspected pathology:

For Soft Tissue Evaluation

• MRI shoulder without IV contrast is the preferred modality for:
  • Rotator cuff injuries (tears, tendinopathy)
  • Non-localized shoulder pain with negative radiographs 1, 2
  • Suspected labral tears (though MR arthrography is superior)

For Bone Detail Assessment

• CT without IV contrast is recommended for:
  • Detailed evaluation of fracture planes
  • Assessment of bone loss
  • Complex fracture characterization 2
  • Metal reduction protocols available if hardware is present

For Labral Tears

• MR Arthrography is the gold standard (86-100% sensitivity) 2
  • Particularly valuable in patients under 35 years
• CT Arthrography is an alternative if MRI is contraindicated
• Standard MRI without contrast is highly effective with optimized imaging equipment 2

For Specific Conditions

1. Bankart or Hill-Sachs lesions:

   • MRI shoulder without IV contrast or MR arthrography 1

2. Prior dislocation/instability with normal radiographs:

   • MRI shoulder without IV contrast or MR arthrography 1

3. Suspected labral tear with normal radiographs:

   • MR arthrography (first choice)
   • CT arthrography (if MRI contraindicated)
   • MRI shoulder without IV contrast 1, 2

4. Complex regional pain syndrome (CRPS):

   • Bone scintigraphy has high specificity but low sensitivity 1

Ultrasound Considerations

• Limited role in chronic shoulder pain evaluation
• Can be used for evaluating rotator cuff and biceps tendon pathology
• Less reliable than MRI for comprehensive assessment 2, 3
• Operator-dependent with varying reports on accuracy 4

Clinical Decision Points

• If no improvement after 3 months of appropriate rehabilitation, consider advanced imaging or surgical consultation 2
• Consider surgical consultation if:
  • Patient is under 30 years with high athletic demands
  • Evidence of significant mechanical symptoms
  • Significant Hill-Sachs lesion or Bankart tear on imaging 2

Common Pitfalls to Avoid

1. Relying solely on radiographs when soft tissue injury is suspected
2. Skipping necessary views in radiographic series (especially axillary view which is crucial for detecting dislocations)
3. Using ultrasound as definitive test for complex shoulder pathology (limited by operator expertise)
4. Delaying advanced imaging when symptoms persist despite conservative treatment
5. Failing to consider age-specific pathologies when selecting imaging modality (e.g., labral tears more common in younger patients, rotator cuff tears more common in older patients) 5

Remember that imaging findings must always be correlated with clinical presentation, as incidental findings are common in shoulder imaging, particularly in older patients.