What are the diagnostic tests for a suspected rotator cuff injury?

Diagnostic Testing for Rotator Cuff Injury

Initial Imaging

Start with plain radiographs of the shoulder (AP views in internal and external rotation plus axillary or scapular Y view) to exclude fractures, dislocations, and osseous pathology before proceeding to advanced imaging. 1, 2

• Radiography is the mandatory first imaging study for any acute shoulder pain, regardless of suspected etiology 1
• This step identifies up to 40% of cases that actually have proximal humerus fractures rather than isolated rotator cuff pathology 2
• Plain films also detect clavicle fractures, scapular fractures, and glenohumeral dislocations that can mimic rotator cuff tears 1, 2

Advanced Imaging: MRI Without Contrast

If radiographs are normal or nonspecific and rotator cuff tear is suspected, MRI shoulder without IV contrast is the optimal next imaging study. 1, 2

Why MRI Without Contrast is Preferred

• The American College of Radiology 2025 guidelines state that MRI without IV contrast is "generally considered the best modality for adequately assessing most soft tissue injuries, including labroligamentous, cartilage, and rotator cuff pathology" 1, 2
• MRI demonstrates 98% sensitivity and 79% specificity for any rotator cuff tears, and 94% sensitivity and 93% specificity for full-thickness tears 2, 3
• In acute trauma settings, post-traumatic joint effusion provides natural distention that enhances soft tissue visualization, making contrast unnecessary 1, 2
• Standard intravenous gadolinium contrast provides no additional diagnostic benefit for rotator cuff evaluation and unnecessarily exposes patients to contrast-related risks 2

MRI Provides Critical Surgical Planning Information

• MRI identifies tear size, tendon retraction, muscle atrophy, and fatty infiltration—all essential for determining whether conservative or surgical management is appropriate 1, 2
• These findings guide the type of operative repair (open, mini-open, arthroscopic, or muscle transfer) and provide postoperative prognosis 1

Alternative Imaging: Ultrasound

Ultrasound is an acceptable alternative to MRI for detecting full-thickness rotator cuff tears when local expertise is available, but has significant limitations. 1

When Ultrasound May Be Appropriate

• Ultrasound shows performance similar to MRI for full-thickness tears, with sensitivities of 90-91% and specificities of 93-95% 1
• The American College of Radiology 2011 guidelines rated both MRI and ultrasound as equally appropriate (rating 9/9) for suspected rotator cuff pathology 1
• Ultrasound may be preferred over MRI in patients with proximal humeral hardware causing MRI susceptibility artifacts 1

Critical Limitations of Ultrasound

• Ultrasound has conflicting evidence and variable interobserver agreement for detecting partial-thickness tears 1, 2
• Performance is highly operator-dependent and may be limited by acute pain restricting range of motion 1, 2
• MRI is preferred when there is suspicion of other intra-articular pathologies (labral tears, cartilage injury) that may coexist with rotator cuff pathology 1, 2
• Ultrasound cannot assess muscle atrophy and fatty infiltration as comprehensively as MRI 1

When to Consider MR Arthrography

MR arthrography should be reserved for cases where non-contrast MRI is equivocal for partial-thickness tears, not as the initial imaging study. 1, 2

• MR arthrography has increased sensitivity for detecting partial-thickness articular surface supraspinatus tears compared with conventional MRI 1
• In acute trauma with post-traumatic effusion already present, the joint is naturally distended, negating the advantage of arthrography 1, 2
• The American College of Radiology 2011 guidelines rated MR arthrography as equally appropriate (9/9) to MRI and ultrasound for suspected retear after prior rotator cuff repair 1

Clinical Examination Findings

Clinical examination should focus on specific tests that predict rotator cuff tears, but imaging is required for definitive diagnosis and surgical planning. 4, 5

High-Yield Clinical Tests

• Three positive findings—supraspinatus weakness (empty can test), weakness of external rotation, and impingement signs—are highly predictive of rotator cuff tear 4
• For patients older than 60 years, only 2 positive tests are needed for high predictive value 4
• Clinical examination alone is 100% sensitive but only 73.8% specific for detecting rotator cuff tears, demonstrating significant examiner bias and overlap with other shoulder pathology 3

Why Clinical Examination Alone is Insufficient

• Clinical examination findings are variable due to examiner bias and therefore diagnostic scope is limited 3
• A careful history and structured physical examination are often sufficient for suspecting rotator cuff disorders, but imaging is required for confirmation 5, 6

Imaging Modalities to Avoid

Do not use CT, FDG-PET/CT, or MRI with intravenous (non-arthrographic) contrast for rotator cuff evaluation. 1, 2

• CT shoulder cannot assess rotator cuff pathology in the acute setting and should not be used for soft-tissue evaluation 1, 2
• FDG-PET/CT and bone scans are not routinely used for rotator cuff tears as they cannot describe tear extent or degree of atrophy 2
• MRI shoulder without and with IV contrast has no relevant literature supporting its use for suspected rotator cuff tears 1, 2

Critical Pitfalls to Avoid

• Do not proceed directly to orthopedic referral without advanced imaging—MRI is essential to confirm diagnosis, characterize tear extent and quality of remaining tendon, and guide appropriate treatment planning 2
• Avoid gadolinium-based contrast agents in dialysis-dependent patients or those with severe renal dysfunction (GFR <30 mL/min/1.73 m²) due to nephrogenic systemic fibrosis risk 2
• Failure to obtain axillary or scapular Y views can result in missed glenohumeral and AC dislocations that appear normal on AP views alone 2
• Do not assume ultrasound can reliably detect partial-thickness tears—variable interobserver agreement makes it less reliable than MRI for this indication 1, 2