E2339. Pearls and Pitfalls of MRI Shoulder Arthrography
Shoulder arthrography is a frequently used method for evaluation of the glenohumeral labrum, articular cartilage and for evaluation of rotator cuff pathology. Studies indicate that MRI shoulder arthrograms have higher accuracy when compared with conventional MRI particularly in younger patients with minimal to no degenerative disease at the glenohumeral joint. The primary advantages afforded by shoulder arthrography include distention of the joint and the addition of contrast which help better disclose subtle labral tears, cartilage defects and undersurface tears of the rotator cuff. Shoulder arthrography can be performed with image guidance using fluoroscopy or ultrasound with either anterior or posterior approaches. The interpretation of MRI arthrograms of the shoulder is also compounded by several normal variants which may confound diagnosis. This exhibit will serve to educate radiologists on common pearls and pitfalls which can occur while performing fluoroscopic or ultrasound guided shoulder arthrography as well as MRI interpretation.
Educational Goals / Teaching Points
This presentation will walk through the standard preparation, technique and approaches for shoulder arthrography using fluoroscopic and ultrasound guidance. Pitfalls related to the procedure will include: solution errors (too much gadolinium in the mixture, no gadolinium in the mixture), injection errors (extravasation into the soft tissues, extravasation from over filling of the joint, injection into the subacromial / subdeltoid bursa, air bubbles in the injection) and interpretation errors (how to differentiate SLAP tears from sublabral recess/foramen). Pearls will include recommendations on how to optimize the procedural technique on fluoroscopy and ultrasound as well as highlighting specific instances where MRA adds superior value to MRI (improved confidence with paralabral cysts, subtle chondrolabral junction tears, undersurface rotator cuff tears, subacromial/subdeltoid bursitis).
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This presentation will elaborate on the common approaches to performing shoulder arthrography using fluoroscopy and ultrasound guidance. For fluoroscopy the anterior approaches of the rotator interval and Schneider techniques will be discussed. For ultrasound there will be a comparison between anterior and posterior techniques approaching the joint from medial to lateral, lateral to medial, as well as straight perpendicular. The exhibit will also discuss practical tips such as rotation and beveling of the needle for optimal intra capsular contrast injection.
Shoulder arthrography is an important adjunct as MRI arthrography of the shoulder adds accuracy to the diagnosis of cartilage, labral and rotator cuff pathology. As such, MRI shoulder arthrography has become an integral component of orthopedic imaging practice. Knowledge of the various methods that the procedure can be performed as well as pitfalls with regards to performing the procedure or interpreting the MRI are essential for the radiologist.