From the Guidelines
The best radiology exam for evaluating the shoulder is MRI, as it provides excellent visualization of soft tissue structures and is generally considered the gold standard for comprehensive shoulder assessment. According to the most recent and highest quality study 1, MRI of the shoulder without IV contrast is the most appropriate study for nonlocalized shoulder pain and negative radiographs. This is because MRI provides detailed images of the rotator cuff, labrum, ligaments, and cartilage, making it ideal for diagnosing tears, tendinopathy, and impingement syndromes.
Key Considerations
- For patients with suspected fractures, dislocations, or bony abnormalities, plain X-rays should be obtained first as they are quick, inexpensive, and effective for initial evaluation 1.
- Ultrasound offers a good alternative for rotator cuff assessment and has the advantages of being dynamic, radiation-free, and less expensive than MRI, though it is highly operator-dependent 1.
- CT scans are particularly useful for complex fractures, bone loss assessment in recurrent dislocations, or preoperative planning 1.
- MR arthrography, which involves injecting contrast into the joint before MRI, provides enhanced detail of labral tears and cartilage injuries, making it the preferred choice for suspected internal derangement, especially in younger, athletic patients with shoulder instability 1.
Specific Scenarios
- In the setting of Bankart or Hill-Sachs lesions detected on radiographs, MRI shoulder without IV contrast or MR arthrography are both appropriate studies for assessing labroligamentous injuries 1.
- When physical examination and history suggest a prior dislocation event, or the presence of instability and radiographs are normal, MRI shoulder without IV contrast or MR arthrography are both appropriate studies 1.
- When physical examination is consistent with a labral tear and radiographs are normal, MR arthrography, CT arthrography, or MRI shoulder without IV contrast are appropriate studies 1.
From the Research
Imaging Modalities for Shoulder Evaluation
The choice of radiology exam for shoulder evaluation depends on the specific condition being assessed.
- Magnetic Resonance Imaging (MRI) is an essential auxiliary tool for evaluating shoulder pain due to its high resolution and sensitivity in depicting soft tissues 2.
- MRI is useful for evaluating disorders of tendons, labrum, and ligaments of the shoulder, as well as common systemic diseases that manifest in the shoulder and disorders of the acromioclavicular joint and bursae 2.
Comparison of MRI and Ultrasound for Rotator Cuff Injuries
For rotator cuff injuries, both MRI and ultrasound (US) are accurate for identifying tears, but each has advantages and shortcomings 3.
- MRI and US are considered reasonable first-line approaches for imaging rotator cuff pathology, with considerable practice variation 3.
- Ultrasound is a low-cost option, and imagers should strive to optimize the quality of shoulder US examinations to build referrer confidence in this modality 3.
- The roles of direct CT and MR arthrography, as well as imaging evaluation of the postoperative rotator cuff, are also important considerations in the diagnosis and treatment of patients with rotator cuff injuries 3.