Best Methods for Measuring Rotator Cuff Tears
MR arthrography is the most accurate method for measuring rotator cuff tears, particularly for partial-thickness tears, though MRI without contrast and ultrasound are also highly effective options for full-thickness tears. 1
Imaging Options for Rotator Cuff Tears
MR Arthrography
- Highest sensitivity for detecting partial-thickness tears (especially articular surface tears)
- Superior for assessing intra-articular pathology
- May have increased sensitivity for detection of partial-thickness articular surface supraspinatus tears compared with conventional MRI 1
- Best option when detailed assessment of partial tears is critical for surgical planning
MRI Without Contrast
- Generally considered the best modality for assessing most soft-tissue injuries, including rotator cuff pathology 1
- High sensitivity and specificity for detection of full-thickness tears
- Lower sensitivity compared to MR arthrography for detection of partial-thickness tears
- Provides comprehensive assessment of surrounding structures (bone marrow, muscles, labrum)
- Allows evaluation of muscle atrophy and fatty infiltration, which are important prognostic factors
Ultrasound
- High sensitivity and specificity for detecting full-thickness rotator cuff tears (90-91% sensitivity, 93-95% specificity) 1
- Performance comparable to MRI for full-thickness tears 2
- More variable performance for partial-thickness tears with conflicting evidence 1
- Advantages include:
- Lower cost
- Dynamic assessment capability
- No contraindications (unlike MRI)
- Real-time examination during shoulder movements 3
- Limitations include:
CT Arthrography
- Similar performance to MR arthrography for full-thickness tears
- Significantly poorer performance for partial-thickness tears 1
- Good alternative for patients with contraindications to MRI
Clinical Decision Algorithm
Initial Assessment:
- Begin with plain radiographs to rule out other pathologies
Selection of Advanced Imaging:
- For suspected full-thickness tears: MRI without contrast, ultrasound, or MR arthrography are all appropriate (similar diagnostic performance)
- For suspected partial-thickness tears: MR arthrography provides highest sensitivity
- For patients with MRI contraindications: Ultrasound or CT arthrography
- For patients with implanted hardware: Ultrasound may be preferred due to fewer artifacts 1
- For patients requiring dynamic assessment: Ultrasound allows real-time examination during movement 3
Special Considerations:
- Institutional preference may drive selection between modalities, as full-thickness tears (which all modalities detect well) are the main decision point for surgical repair 1
- Office-based bedside ultrasound by trained physicians can reasonably rule out medium/large full-thickness tears but may miss small tears (<15mm) 4
Important Caveats
- No imaging method should be used as a screening tool in patients with chronic shoulder pain without appropriate clinical indications 3
- Physical examination tests alone are insufficient for diagnosing rotator cuff tears and should be correlated with imaging findings 5
- Ultrasound performed by less experienced operators may miss small full-thickness tears that would be detected by expert radiologists 4
- MRI findings of peroneal tendon pathology should be interpreted carefully as asymptomatic patients may have tears 6
- The selection between MRI, MR arthrography and ultrasound should consider availability, cost, patient factors, and the specific clinical question being addressed
In summary, while MR arthrography offers the highest sensitivity for partial-thickness tears, all three main modalities (MRI, MR arthrography, and ultrasound) provide excellent detection of full-thickness tears, which are the primary determinant for surgical intervention.