KINEMATIC MR-IMAGING OF THE SHOULDER - NORMAL PATTERNS

OBJECTIVE. We performed this study tb define the normal patterns of th e gleno-humeral joint with kinematic MR imaging in healthy volunteers. SUBJECTS AND METHODS. Twenty healthy volunteers (39 shoulders) were s tudied with a 1.5-T imager. Successive fast low-angle shot images (75/ 11 [TR/TE], 15 degrees flip angle) were obtained in the axial plane fr om full internal to full external rotation at the superior, middle, an d inferior glenoid levels. RESULTS. The free margin of the anterior la brum was seen to be slightly mobile and its base was always fixed. The anterior labrum showed changes in shape and signal intensity during i nternal rotation (54%). The posterior labrum remained motionless in 97 % of patients and no shape or signal-intensity changes were noted duri ng internal rotation. The anterior joint capsule was taut during exter nal and internal rotation, exhibited a slack pattern in 51% of patient s, and a folded pattern in 14% of patients. CONCLUSION. Kinematic MR i maging, which permits dynamic evaluation of the various anatomic compo nents that may be involved in shoulder instability; also provides info rmation on the labrocapsular ligamentous complex.