Ultrasonography and magnetic resonance imaging changes in patients with polymyalgia rheumatica treated by tocilizumab.

Background: This study assessed inflammatory changes using ultrasound (US) and magnetic resonance imaging (MRI) in patients taking tocilizumab for polymyalgia rheumatica (PMR).

Methods: Eighteen patients were included in the prospective open-label TENOR study and received three tocilizumab infusions, without corticosteroids. B-mode and power Doppler US and MRI (T1 and T2-short time inversion recuperation weighted sequences) of the hips and shoulders were performed at weeks 0, 2, and 12. Subacromial, trochanteric, and iliopsoas bursitis and intraarticular glenohumeral and coxofemoral effusions/synovitis were scored from 0 to 3. Changes over time and US-MRI correlations were evaluated.

Results: At baseline, the proportions of shoulders and hips with bursitis were 93 and 100% by MRI and 61 and 13% by US; and the corresponding proportions for intraarticular effusions/synovitis were 100 and 100% by MRI and 57 and 53% by US. Imaging findings did not improve during the first two treatment weeks. From baseline to week 12, bursitis improved significantly at all four joints by MRI (P = 0.005) and US (P = 0.029) and intraarticular effusions/synovitis by US only (P = 0.001). The proportion of abnormalities that improved by week 12 was 42% by MRI and 37% by US. MRI detected bursitis in a larger proportion of hips (73% versus 13%) and US in a larger proportion of shoulders (57% versus 28%), whereas no difference was found for intraarticular effusions/synovitis. At baseline, agreement between US and MRI findings was poor.

Conclusions: US and MRI showed significant improvements in inflammatory lesions during tocilizumab treatment of PMR.