Fat Suppression Magnetic Resonance Imaging in Shoulders of Patients with Polymyalgia Rheumatica

Objective. To evaluate the sites of inflammatory process in the shoulders of patients with polymyalgia rheumatica (PMR) using fat suppressed magnetic resonance imaging (MRI). Methods. Six consecutive, untreated new patients with PMR were investigated. Five patients with early rheumatoid arthritis (RA) and 4 patients with early psoriatic arthritis (PsA) with bilateral shoulder symptoms served as a control group. Bilateral shoulder fat-suppressed MRI sequences were performed in all patients and controls. We evaluated the presence of joint synovitis, bursitis, tenosynovitis, and bone and soft tissue edema. Results. Bilateral subacromial/subdeltoid bursitis was found in all patients with PMR, in 1/5 (20%) patients with RA (p <0.05), and in none with PsA (p <0.02). Glenohumeral synovitis was present in all case and controls. Biceps tenosynovitis was observed in 4/6 (67%) patients with PMR, in 4/5 (80%) with RA (not significant, NS), and in all 4 patients with PsA (NS). No evidence of bone edema adjacent to the joint capsule and entheseal insertions or in the soft tissues was present in either cases or controls. Conclusion. The absence of extracapsular abnormalities in the early shoulder disease of PMR does not confirm the hypothesis of a capsular-based disorder.