What is the best imaging modality to evaluate for tenosynovitis?

Best Imaging Modality for Tenosynovitis Evaluation

MRI is the best imaging modality for evaluating tenosynovitis, with ultrasound being an excellent first-line alternative when available with appropriate expertise. 1, 2

Comparison of Imaging Modalities

MRI

• Considered the gold standard for imaging synovitis and tenosynovitis in inflammatory arthritis 2
• More sensitive than ultrasound in identifying tenosynovitis 3
• Superior for evaluating the extent of tenosynovitis, particularly in soft tissue 4
• Enhanced MRI (with contrast) significantly outperforms non-enhanced imaging for detection of tenosynovitis (p<0.001) 5
• Allows visualization of deeper structures and associated bone marrow changes 1

Ultrasound

• Excellent first-line imaging modality due to accessibility, cost-effectiveness, and ability to perform dynamic assessment 1
• Well-suited for evaluating superficial tendon structures of the hand and wrist 1
• Can detect more joint and tendon sheath effusions than MRI in some cases 3
• Baseline tenosynovitis on ultrasound is predictive of erosive progression at 1 year (OR 7.18) and 3 years (OR 3.4) 3
• Allows for real-time, dynamic assessment and can guide therapeutic injections 1

Other Modalities

• CT is not routinely used for tenosynovitis and has limited ability to show synovial hypertrophy 3
• Conventional radiography has poor sensitivity for soft tissue abnormalities including tenosynovitis 3
• Nuclear medicine techniques (scintigraphy, PET) can detect inflammation but lack specificity 3

Clinical Approach to Imaging Tenosynovitis

1. Initial Assessment:

   • Begin with radiographs to exclude other pathologies 1
   • Progress to advanced imaging based on clinical suspicion and availability 1

2. Choose Between MRI and Ultrasound Based On:

   • Location and depth of suspected tenosynovitis 1
   • Need for evaluation of associated structures 1
   • Local expertise and equipment availability 1

3. MRI Protocol Considerations:

   • Contrast-enhanced MRI significantly improves detection compared to T2-weighted imaging alone (sensitivity increased from 40-67% to reference standard) 5
   • Include both T1-weighted post-contrast and T2-weighted sequences for optimal evaluation 2
   • Consider diffusion-weighted imaging (DWI) which has shown 92-97% sensitivity for tenosynovitis 6

Important Clinical Considerations

• Both ultrasound and MRI significantly outperform clinical examination in detecting tenosynovitis 3, 1
• MRI flexor tenosynovitis has been described as a predictor of early rheumatoid arthritis (sensitivity 0.60, specificity 0.73) 1
• In inflammatory arthritis, MRI can detect subclinical tenosynovitis even in patients in clinical remission 2
• The American College of Radiology rates MRI shoulder without contrast (9/9) and ultrasound shoulder (9/9) as equally appropriate for evaluating questionable bursitis or long head of biceps tenosynovitis 3

Pitfalls and Caveats

• Blood vessels and adjacent synovitis can contribute to false detections in automatic measurements of tenosynovitis on MRI 7
• Ultrasound is highly operator-dependent and requires specific expertise for optimal evaluation of tenosynovitis 1
• MRI has limitations including higher cost, less accessibility, and contraindications for certain patients 1
• Enhanced MRI is significantly more sensitive than non-enhanced imaging, so lack of contrast may lead to missed diagnoses 5