[Diagnostic imaging of the rotator cuff]

The importance of imaging modalities in the evaluation of the rotator cuff has increased thanks to the development of non-invasive methods. An optimum application of the technique, appreciation of the anatomical details and imaging pitfalls, and proper interpretation of clinical findings should be incorporated in order to increase diagnostic accuracy. Ultrasonography (US) and magnetic resonance imaging (MRI) are commonly used for rotator cuff pathologies. The former has a high diagnostic accuracy in full-thickness tears, but requires operator dependency and long-term training. Both US and MRI require sophisticated equipment and present difficulties in distinguishing between partial and small full-thickness tears. In full-thickness tears, MRI may be more appropriate if imaging findings are likely to alter the course of surgical treatment. However, it is not necessary in patients in whom US may clearly show tendinosis. Magnetic resonance imaging or MR arthrography may be required in order to evaluate partial tears or suspicious small full-thickness tears in patients unresponsive to conservative therapy. A close collaboration is essential between the radiologist and the shoulder surgeon in the interpretation of clinical findings. The diagnostic accuracy will increase if the examinations are performed by a musculoskeletal radiologist.