title: MRI bone oedema scores are higher in the arthritis mutilans form of psoriatic arthritis and correlate with high radiographic scores for joint damage.
abstract: BACKGROUND
  The aim of this study was to investigate the magnetic resonance imaging (MRI) features of bone disease in the arthritis mutilans (AM) form of psoriatic arthritis (PsA).
  
  
  METHODS
  Twenty-eight patients with erosive PsA were enrolled (median disease duration of 14 years). Using x-rays of both hands and feet, 11 patients were classified as AM and 17 as non-AM (erosive psoriatic arthritis without bone lysis)by two observers. MRI scans (1.5T) of the dominant hand (wrist and fingers scanned separately) were obtained using standard contrast-enhanced T1-weighted and fat-saturated T2-weighted sequences. Scans were scored separately by two readers for bone erosion, oedema and proliferation using a PsA MRI scoring system. X-rays were scored for erosions and joint space narrowing.
  
  
  RESULTS
  On MRI, 1013 bones were scored by both readers. Reliability for scoring erosions and bone oedema was high (intraclass correlation coefficients = 0.80 and 0.77 respectively) but only fair for bone proliferation (intraclass correlation coefficient = 0.42). MRI erosion scores were higher in AM patients (53.0 versus 15.0, p = 0.004) as were bone oedema and proliferation scores (14.7 versus 10.0, p = 0.056 and 3.6 versus 0.7, p = 0.003 respectively). MRI bone oedema scores correlated with MRI erosion scores and X-ray erosion and joint space narrowing scores (r = 0.65, p = 0.0002 for all) but not the disease activity score 28-C reactive protein (DAS28CRP) or pain scores.
  
  
  CONCLUSIONS
  In this patient group with PsA, MRI bone oedema, erosion and proliferation were all more severe in the AM-form. Bone oedema scores did not correlate with disease activity measures but were closely associated with X-ray joint damage scores. These results suggest that MRI bone oedema may be a pre-erosive feature and that bone damage may not be coupled with joint inflammation in PsA.
authors.affiliation: Department of Molecular Medicine and Pathology, University of Auckland, Park Road, Auckland 1010, New Zealand. ytan088@ec.auckland.ac.nz
authors.forename: Yu M
authors.initials: YM
authors.lastname: Tan
authors.forename: Mikkel
authors.initials: M
authors.lastname: Østergaard
authors.forename: Anthony
authors.initials: A
authors.lastname: Doyle
authors.forename: Nicola
authors.initials: N
authors.lastname: Dalbeth
authors.forename: Maria
authors.initials: M
authors.lastname: Lobo
authors.forename: Quentin
authors.initials: Q
authors.lastname: Reeves
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Robinson
authors.forename: William J
authors.initials: WJ
authors.lastname: Taylor
authors.forename: Peter B
authors.initials: PB
authors.lastname: Jones
authors.forename: Karen
authors.initials: K
authors.lastname: Pui
authors.forename: Jamie
authors.initials: J
authors.lastname: Lee
authors.forename: Fiona M
authors.initials: FM
authors.lastname: McQueen
mesh_terms: D000328:Adult; D015535:Arthritis, Psoriatic / Q000000981:diagnostic imaging* / Q000473:pathology*; D001175:Arthrography; D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000473:pathology*; D004487:Edema / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D007596:Joints / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008875:Middle Aged