title: Whole-body MRI of patients with polymyalgia rheumatica identifies a distinct subset with complete patient-reported response to glucocorticoids.
abstract: OBJECTIVE
  To determine whether whole-body MRI defines clinically relevant subgroups within polymyalgia rheumatica (PMR) including glucocorticoid responsiveness.
  
  
  METHODS
  22 patients with PMR and 16 with rheumatoid arthritis (RA), untreated and diagnosed by consultant rheumatologists, underwent whole-body, multiple-joint MRI, scored by two experts. Patients with PMR reported whether they felt 'back to normal' on glucocorticoid therapy and were followed for a median of 2 years.
  
  
  RESULTS
  All patients with PMR were deemed to respond to glucocorticoids clinically. A characteristic pattern of symmetrical, extracapsular inflammation, adjacent to greater trochanter, acetabulum, ischial tuberosity and/or symphysis pubis, was observed in 14/22 of the PMR cases. In PMR, this pattern was associated with complete glucocorticoid response (p=0.01), higher pretreatment C-reactive protein (CRP) and serum interleukin-6 (IL-6), and better post-treatment fatigue and function. Only 1/14 in the extracapsular group could stop glucocorticoids within 1 year, compared with 4/7 of the others. A score derived from the five sites discriminating best between PMR and RA correlated with IL-6 (p<0.002). IL-6 levels ≥16.8 pg/mL had 86% sensitivity and 86% specificity for the extracapsular MRI pattern.
  
  
  CONCLUSIONS
  A subset of patients with rheumatologist-diagnosed PMR had a characteristic, extracapsular pattern of MRI inflammation, associated with elevated IL-6/CRP and with complete patient-reported glucocorticoid responsiveness.
authors.affiliation: Leeds Institute for Rheumatic and Musculoskeletal Medicine, Leeds, UK NIHR-Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: Sarah Louise
authors.initials: SL
authors.lastname: Mackie
authors.affiliation: Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Colin Thomas
authors.initials: CT
authors.lastname: Pease
authors.affiliation: Department of Radiology, Shimane University, Izumo, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Fukuba
authors.affiliation: Leeds Institute for Rheumatic and Musculoskeletal Medicine, Leeds, UK.
authors.forename: Emma
authors.initials: E
authors.lastname: Harris
authors.affiliation: Leeds Institute for Rheumatic and Musculoskeletal Medicine, Leeds, UK NIHR-Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Emery
authors.affiliation: Leeds Institute for Rheumatic and Musculoskeletal Medicine, Leeds, UK NIHR-Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK University of Manchester Centre for Imaging Sciences, Manchester, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Hodgson
authors.affiliation: Leeds Institute for Rheumatic and Musculoskeletal Medicine, Leeds, UK NIHR-Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: Jane
authors.initials: J
authors.lastname: Freeston
authors.affiliation: Leeds Institute for Rheumatic and Musculoskeletal Medicine, Leeds, UK NIHR-Leeds Musculoskeletal Biomedical Research Unit, Leeds, UK.
authors.forename: Dennis
authors.initials: D
authors.lastname: McGonagle
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011111:Polymyalgia Rheumatica / Q000175:diagnosis* / Q000188:drug therapy; D011239:Prednisolone / Q000627:therapeutic use*; D016896:Treatment Outcome; D051598:Whole Body Imaging / Q000379:methods*
chemical_list: D005938:Glucocorticoids; D011239:Prednisolone
keywords: Cytokines; Magnetic Resonance Imaging; Polymyalgia Rheumatica