title: Computed tomography scanning facilitates the diagnosis of sacroiliitis in patients with suspected spondylarthritis: results of a prospective multicenter French cohort study.
abstract: OBJECTIVE
  To assess the performance of computed tomography (CT) scanning for ascertaining sacroiliitis in patients with suspected spondylarthritis (SpA).
  
  
  METHODS
  The Echography in Spondylarthritis French cohort consists of 489 patients with suspected SpA. At baseline, all patients underwent clinical examination, HLA-B typing, and pelvic radiography. Pelvic CT scanning was performed if sacroiliitis on radiography was considered uncertain or if patients presented with buttock pain duration of >6 months. A set of 100 paired radiographs and CT scans was read in a blinded manner by 2 radiologists, and the kappa coefficient was used to assess their interreader reliability. One of the radiologists read the 173 available pairs of radiographs and CT scans performed at baseline.
  
  
  RESULTS
  After training, interreader reliability was moderate for sacroiliitis grading on radiographs (κ = 0.59), excellent on CT scans (κ = 0.91), and excellent for ascertaining sacroiliitis on both radiographs (κ = 1) and CT scans (κ = 0.96). The first and second readers considered the quality of imaging to be excellent in 66% and 67%, respectively, of the radiographs (κ = 0.88) and in 93% and 92%, respectively, of the CT scans (κ = 0.93). Concordance between radiographs and CT scans was low for sacroiliitis grading (κ = 0.08) or ascertainment (κ = 0.16). Definite sacroiliitis was ascertained on radiographs in 6 patients (3.5%) (confirmed by CT scans in 4 patients) and on CT scans in 32 patients (18.5%). A history of uveitis was associated with definite sacroiliitis on radiographs (P = 0.04) and CT scans (P < 0.0001).
  
  
  CONCLUSIONS
  Definite sacroiliitis was underestimated by radiography, as compared to CT scanning. CT scanning should facilitate the diagnosis of ankylosing spondylitis in patients with suspected SpA.
authors.affiliation: Université de Brest, EA2216, and Centre Hospitalier Universitaire de Brest, Brest, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Devauchelle-Pensec
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: D'Agostino
authors.forename: Julien
authors.initials: J
authors.lastname: Marion
authors.forename: Marie
authors.initials: M
authors.lastname: Lapierre
authors.forename: Sandrine
authors.initials: S
authors.lastname: Jousse-Joulin
authors.forename: Danielle
authors.initials: D
authors.lastname: Colin
authors.forename: Isabelle
authors.initials: I
authors.lastname: Chary-Valckenaere
authors.forename: Christian
authors.initials: C
authors.lastname: Marcelli
authors.forename: Damien
authors.initials: D
authors.lastname: Loeuille
authors.forename: Philippe
authors.initials: P
authors.lastname: Aegerter
authors.forename: Sandrine
authors.initials: S
authors.lastname: Guis
authors.forename: Philippe
authors.initials: P
authors.lastname: Gaudin
authors.forename: Maxime
authors.initials: M
authors.lastname: Breban
authors.forename: Alain
authors.initials: A
authors.lastname: Saraux
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010045:Outpatients; D010388:Pelvis / Q000000981:diagnostic imaging; D011446:Prospective Studies; D015203:Reproducibility of Results; D058566:Sacroiliitis / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D016037:Single-Blind Method; D013167:Spondylitis, Ankylosing / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*