The most common indication for referring a patient for MR imaging of the shoulder is rotator cuff disease, inclusive of clinical manifestations of impingement and shoulder instability. Regardless of the suspected diagnosis, however, a comprehensive evaluation is warranted, given the often poorly defined shoulder symptoms, with considerable overlap between symptoms referable to microinstability, superior labral tears, and rotator cuff disease. In addition, early degenerative changes of the glenohumeral joint may manifest as pain and disability, mimicking cuff disease. For that reason, inclusion of pulse sequences optimized for visualization of cartilage in the imaging protocol is suggested. These pulse sequences provide valuable information regarding the integrity of the articular surface of the glenohumeral joint, which may demonstrate focally significant pathology despite the presence of normal plain radiographs.

Optimized FSE protocols can provide assessment of articular cartilage, as well as the capsular labral complex, rotator cuff and surrounding soft tissue structures1. Today's FSE sequences provide high spatial resolution images in relatively short acquisition times with minimal blurring. (Fig. 4.1)

Figure 4.1 (click on image for enlarged view) Axial FSE MR image demonstrating an arthroscopically confirmed normal capsulolabral complex. With appropriate pulse sequence parameters, differential contrast may be obtained on fast spin echo techniques between articular cartilage and fibrocartilage. With higher resolution techniques, the middle glenohumeral ligament may be discerned as a discrete structure from the adjacent capsule.

In addition, the utility of fast spin echo sequences in the post-operative shoulder is well demonstrated. The multiple 180° refocusing pulses and the diminished inter-echo spacing in recent versions of this pulse sequence result in decreased susceptibility artifact. In the post-operative shoulder, susceptibility artifacts can be caused by either metallic debris from the arthroscope or by suture anchor fixation devices and/or staples from either rotator cuff repair or instability procedures.

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¹ Sonin AH, Peduto AJ, Fitzgerald SW, et al. MR imaging of the rotator cuff mechanism: comparison of spin-echo and turbo spin-echo sequences. Am. J. Roentgenol., 167(2), 333-338, 1996.