According to new research findings presented at the recent 2019 ACR/ARP Annual Meeting, the use of gadolinium-enhanced MRI in shoulders of patients with polymyalgia rheumatica may contribute to more accurate diagnosis and prediction of recurrence. Gd-enhanced MRI displayed capsulitis, rotator cuff tendinitis and focal osteitis in shoulders that were relatively specific to patients with polymyalgia rheumatica.
PMR is a chronic musculoskeletal disorder that causes aching and stiffness about the upper arms, neck, lower back and thighs. It is a common cause of widespread aching and stiffness that affects adults over the age of 50, especially Caucasians. Because PMR does not often cause swollen joints, it may be hard to recognize. PMR is clinically diagnosed based on symptoms, but accurate diagnosis is difficult because the symptoms may occur in many other rheumatic diseases. While MRI may visualize bone and muscle lesions, its application in PMR has not been established, so a cross-sectional, follow-up study was carried out to evaluate Gd-enhanced MRI in the shoulder of PMR patients to assess whether it could improve diagnostic accuracy.
“The diagnosis of PMR remains challenging. Bird’s Classification Criteria composed of the combination of clinical symptoms is highly sensitive but is low in specificity and requires careful diagnosis of exclusion,” says Dr. Kazuro Kamada, a rheumatologist at Tomakomai City Hospital in Japan, and the study’s lead author. “The EULAR/ACR Provisional Classification Criteria using ultrasound findings improve specificity, but the sensitivity was not enough. So, we need a new diagnostic tool with high specificity and sensitivity for PMR.”
Participants in the study included 175 patients with bilateral shoulder pain who fulfilled the Bird classification criteria for PMR. Out of these, 137 patients received both Gd-enhanced MRI and ultrasonography on their shoulders. At least two rheumatologists diagnosed PMR in 58 of the patients, and independent radiologists evaluated their MRI and ultrasonography findings. The findings showed that PMR patients had significant enhancement of joint capsule or rotator cuff tendon and focal bone edema in humerus heads.
MRI had 76 percent sensitivity and 85 percent specificity, higher than ultrasonography, which had 50 percent sensitivity and 72 percent specificity. These findings led the study’s authors to conclude that Gd-enhanced MRI of the shoulder can play a useful clinical role in patients with PMR. “Rheumatologists will diagnose PMR with confidence using gadolinium-enhanced MRI with high sensitivity and specificity, which will lead to decreasing misdiagnosis of PMR,” says Dr. Kamada. “Moreover, rheumatologists can consider using disease-modifying anti-rheumatic drugs from the early stage for PMR patients if recurrences can be predicted by Gd-enhanced MRI. We are going to validate the results in a larger cohort in order to optimize and standardize the Gd-enhanced MRI procedure for PMR to apply in real-world clinical practice.”