[Shoulder imaging: what is the best modality?].

Specific pathologies of the shoulder include instabilities in young patients and tendinopathies in older patients. The choice of imaging modality depends on the information expected from each technique. In case of instability, plain films demonstrate bone abnormalities such as Hill Sachs and/or Bankart lesions. Arthro-CT or arthro-MRI need not be in all cases but can provide additional information performed about the intraarticular structures and the glenoid labrum. The rotator cuff is initially evaluated by plain films which demonstrate anatomical conditions resulting in impingement syndrome as well as indirect signs of tendinopathy. Direct visualization of tendons may be achieved by US, arthro-CT, arthro-MRI. US is a dynamic, non invasive and accurate technique for evaluation of rotator cuff tear but is very operator-dependent. Arthro-CT is more reproductive and reveals accurately partial tear as well as anterior tears involving biceps or subscapularis tendons. MRI is very useful to visualize the rotator cuff and adjacent bony structures. Nevertheless, MRI is still limited by its cost, accessibility and variable quality.