title: What is the reliability of non-trained investigators in recognising structural MRI lesions of sacroiliac joints in patients with recent inflammatory back pain? Results of the DESIR cohort.
abstract: OBJECTIVE
  The objective of this study was to evaluate the reliability of recognising structural lesions on MRI (erosions, fatty lesions, ankylosis) of the sacroiliac joints (MRI-SIJ) in clinical practice compared to a central reading in patients with a possible recent axial spondyloarthritis (axSpA).
  
  
  METHODS
  Patients aged 18-50 years, with recent (<3 years) and chronic (≥3 months) inflammatory back pain, suggestive of axSpA were included in the DEvenir des Spondyloarthrites Indifférenciées Récentes (DESIR) cohort. MRI-SIJ structural lesions were scored by non-trained local readers, and by two trained central readers. Local readers scored each SIJ as normal, doubtful or definite lesions. Central readers scored separately each type of lesion. The central reading (mean of the two central readers' scores) was the external standard. Agreement (κ) was calculated first between local (3 definitions of a positive MRI-SIJ) and central readings (9 definitions), and then between the two central readers.
  
  
  RESULTS
  664/708 patients with complete available images were included. Agreements between local and central readings were overall 'fair', except when considering at least 2 or 3 fatty lesions and at least 3 erosions and/or fatty lesions where agreement was 'moderate'. Agreement between central readers was similar. MRI-SIJ was positive for 52.6% of patients according to central reading (at least 1 structural lesion) and for 35.4% of patients according to local reading (at least unilateral 'doubtful' or 'definite' structural lesions).
  
  
  CONCLUSIONS
  Agreement on a positive structural MRI-SIJ was fair to moderate between local and central readings, as well as between central readers. The reliability improved when fatty lesions were considered.
  
  
  BACKGROUND
  NCTO 164 8907.
authors.affiliation: Department of Rheumatology , Hôpital Henri Mondor , Créteil , France.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Jacquemin
authors.affiliation: Department of Rheumatology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: Roxana
authors.initials: R
authors.lastname: Rubio Vargas
authors.affiliation: Department of Rheumatology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: Rosaline
authors.initials: R
authors.lastname: van den Berg
authors.affiliation: Department of Radiology , Hôpital Cochin , Paris , France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Thévenin
authors.affiliation: Department of Radiology , Clinique Hartmann , Neuilly-sur-Seine , France.
authors.forename: Gregory
authors.initials: G
authors.lastname: Lenczner
authors.affiliation: Department of Radiology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: Monique
authors.initials: M
authors.lastname: Reijnierse
authors.affiliation: Clinical Investigation Center 1430, AP-HP and Inserm, Hôpital Henri Mondor , Créteil , France.
authors.forename: Salah
authors.initials: S
authors.lastname: Ferkal
authors.affiliation: Clinical Investigation Center 1430, AP-HP and Inserm, Hôpital Henri Mondor , Créteil , France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Le Corvoisier
authors.affiliation: Department of Radiology , Hôpital Henri Mondor , Créteil , France.
authors.forename: Alain
authors.initials: A
authors.lastname: Rahmouni
authors.affiliation: Department of Rheumatology , Hôpital Brabois , Nancy , France.
authors.forename: Damien
authors.initials: D
authors.lastname: Loeuille
authors.affiliation: Department of Radiology , Hôpital Cochin , Paris , France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Feydy
authors.affiliation: Department of Rheumatology , Hôpital Cochin , Paris , France.
authors.forename: Maxime
authors.initials: M
authors.lastname: Dougados
authors.affiliation: Department of Rheumatology , Leiden University Medical Center , Leiden , The Netherlands.
authors.forename: Désirée
authors.initials: D
authors.lastname: van der Heijde
authors.affiliation: Department of Rheumatology, Hôpital Henri Mondor, Créteil, France; Université Paris Est Créteil, EA 7379-EpidermE, F-94010, Créteil, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Claudepierre
keywords: Epidemiology; Magnetic Resonance Imaging; Spondyloarthritis