Localized Myofascial Inflammation Revealed by Magnetic Resonance Imaging in Recent-onset Polymyalgia Rheumatica and Effect of Tocilizumab Therapy

Abstract

Objective.To assess the prevalence of myofascial inflammatory lesions visible by magnetic resonance imaging (MRI) and their changes after tocilizumab (TCZ) therapy in active polymyalgia rheumatica (PMR).Methods.We conducted a posthoc analysis of data from the TENOR study of TCZ monotherapy in PMR. The 18 patients each received TCZ injections at weeks 0, 4, and 8. The shoulder and pelvic girdles were assessed at baseline then at weeks 2 and 12 using T1- and T2- short-tau inversion recovery–weighted MRI. Radiologists blinded to patient data assessed each muscle group for localized myofascial inflammation on baseline, Week 2, and Week 12 MRI. Reproducibility was estimated by having 2 radiologists assess the Week 2 MRI of 13 patients, then computing the κ coefficient.Results.For myofascial lesion detection, intraobserver reproducibility was almost perfect (κ = 0.890) and interobserver reproducibility was substantial (κ = 0.758). At baseline, all patients had at least 1 inflammatory myofascial lesion; sites involved were the shoulder in 10 (71.4%) patients, hip in 13 (86.7%), ischial tuberosity in 9 (60.0%), and pubic symphysis in 12 (80.0%). Sites involved at Week 12 were the shoulder in 8 patients (53.3%), hip in 5 (33.3%), ischial tuberosity in 1, and pubic symphysis in 3 (20.0%). At Week 12, of 103 muscle groups studied in all, 43 (41.7%) had no inflammatory lesions, compared to 33 at baseline (p = 0.002); improvements were noted in 66 (64.1%) muscle groups, worsening in 2 (1.9%), no change in 35 (34.0%; p = 0.034).Conclusion.Localized myofascial inflammatory lesions are common in recent-onset PMR and improve during TCZ therapy. Clinicaltrials.gov (NCT01713842).

Diagnostic value of [18F]FDG-PET/CT in polymyalgia rheumatica: a systematic review and meta-analysis

“…Various imaging modalities have been introduced in the diagnostic work-up of suspected PMR. Ultrasonography and magnetic resonance imaging (MRI) may reveal subacromialsubdeltoid bursitis, biceps tenosynovitis, glenohumeral synovitis, coxofemoral synovitis and/or trochanteric bursitis [2,[5][6][7][8][9]. These abnormalities are more accurately detected by MRI than ultrasonography [10].…”

“…MRI scans covering selected areas (e.g. shoulder and hip girdle) and also total body MRI may be helpful in the evaluation of PMR [7][8][9][10].…”

An update on polymyalgia rheumatica

“…Typical findings in PMR include a characteristic pattern of symmetrical inflammation in the greater trochanter, acetabulum and ischial tuberosity, reported in 64% of patients with PMR in one study [64]. In another study by Laporte et al., all patients with new‐onset PMR had at least one site of myofascial inflammation, most commonly in the hips, followed by pubic symphysis, shoulders and ischial tuberosity [65]. Advantages of MRI over ultrasound include that MRI is more specific with less interobserver variation in the assessment of vasculitis.…”

Imaging in polymyalgia rheumatica: which technique to use?

“…Another interesting and recent study by Laporte et al described localised, myofascial inflammations identified by MRI at the shoulder and pelvic girdles in patients with active, recent-onset PM. Myofascial findings might, therefore, aid in PM diagnosis (22). Involvement of muscles on MRI has not been found in RA (23) nor spondyloarthritis (24).…”