Best Imaging for Lateral Epicondylitis When MRI is Contraindicated
Ultrasound (US) of the elbow is the best alternative imaging modality for diagnosing lateral epicondylitis when MRI is contraindicated. 1, 2
Primary Recommendation: Ultrasound
The American College of Radiology recommends ultrasound as usually appropriate for evaluating suspected tendon or ligament injury when radiographs are normal or indeterminate. 1, 2 This directly applies to lateral epicondylitis, which is a tendinopathy of the common extensor tendon origin.
Diagnostic Performance of Ultrasound
US demonstrates moderate to good diagnostic accuracy with sensitivity of 64.25%, specificity of 85.19%, and overall accuracy of 72.73% for diagnosing and grading common extensor tendon tears 1
Advanced US techniques significantly improve diagnostic performance: 1
- Sonoelastography achieves sensitivity of 95.2%, specificity of 92%, and accuracy of 93.5%
- Superb microvascular imaging combined with conventional US performs best with sensitivity of 94%, specificity of 98%, and accuracy of 96%
Key Sonographic Findings to Identify
Look for these specific pathologic features on ultrasound examination: 3, 4
- Focal hypoechoic areas in the deep part of the common extensor tendon (most common finding, representing collagen degeneration with fibroblastic proliferation)
- Hyperemia on Doppler imaging indicating neovascularization
- Intratendinous splits or cleavage tears (partial or complete)
- Pain provocation when the US probe passes over the pathologic area
- Thickening or thinning of the tendon substance
Clinical Advantages of Ultrasound
- US is simple, cost-effective, and readily available for confirming the clinical diagnosis 3, 5
- Dynamic real-time assessment allows evaluation of the entire muscle-tendon unit from the wrist to the lateral epicondyle 3
- Guides therapeutic interventions by targeting pathologic areas for needling or injection 3
- Eliminates most differential diagnoses including lateral collateral ligament involvement 4
Alternative Imaging Options (Limited Utility)
CT and CT Arthrography
There is limited evidence supporting CT or CT arthrography for detecting tendon tears or chronic epicondylalgia. 1 These modalities are not recommended as alternatives to MRI for lateral epicondylitis.
Three-Phase Bone Scan
Bone scan has limited evidence for routine use in epicondylalgia, though it can detect chronic epicondylalgia in some cases 1. This is not a first-line alternative given the superior soft tissue visualization with ultrasound.
Important Clinical Context
- Lateral epicondylitis is primarily a clinical diagnosis based on history and physical examination 3, 6
- Imaging should be reserved for cases where: 2
- Clinical tests are inconclusive
- Symptoms persist despite appropriate treatment
- Surgical planning is being considered
- The diagnosis typically involves the dominant arm in 75% of cases and results from repetitive occupational or athletic activities involving wrist extension and supination 2, 6
Common Pitfalls to Avoid
- Do not order CT for lateral epicondylitis evaluation as it provides no useful information about tendon pathology 1
- Ensure the sonographer examines the entire common extensor tendon origin including the extensor carpi radialis brevis (deep fibers) and extensor digitorum (superficial fibers) 4
- Check for lateral collateral ligament involvement as this occurs in approximately 11% of cases and may alter management 4
- Remember that US is operator-dependent - ensure the examination is performed by someone experienced in musculoskeletal ultrasound 1