Magnetic resonance imaging of the shoulder.

Magnetic resonance imaging (MRI) is proving to be an effective means for evaluating the shoulder. The use of a surface coil and high resolution scanning techniques have allowed detailed analysis of the normal anatomy of the shoulder. When evaluating for shoulder pathology, the choice of imaging plane and pulse sequencing will be determined by the suspected pathology. In patients with impingement syndrome, subacromial bursitis, supraspinatus tendinitis, and supraspinatus tendon tear can be differentiated, and the offending component of the subacromial are traumatizing these soft tissues can be identified. MRI is also useful in determining the extent of retraction of the supraspinatus musculotendinous junction and the amount of muscle atrophy in cases of massive, chronic tears. Labral tear or attenuation due to glenohumeral instability can be imaged without the injection of contrast material, and MRI can identify those patients with multidirectional instability. Because of the ability to directly depict bone marrow, MRI is the imaging method of choice for the evaluation of early ischemic necrosis of the humeral head.