title: Combining information obtained from magnetic resonance imaging and conventional radiographs to detect sacroiliitis in patients with recent onset inflammatory back pain.
abstract: OBJECTIVE
  To compare the contribution of changes on magnetic resonance imaging (MRI) and conventional radiography (CR) in the sacroiliac joints of patients with recent onset inflammatory back pain (IBP) in making an early diagnosis of spondyloarthritides.
  
  
  METHODS
  The study involved 68 patients with IBP (38% male; mean (SD) age, 34.9 (10.3) years) with symptom duration less than two years. Coronal MRI of the sacroiliac joints was scored for inflammation and structural changes, and pelvic radiographs were scored by the modified New York (mNY) grading. Agreement between MRI and CR was analysed by cross tabulation per sacroiliac joint and per patient.
  
  
  RESULTS
  A structural change was detected in 20 sacroiliac joints by MRI and in 37 by CR. Inflammation was detected in 36 sacroiliac joints by MRI, and 22 of these showed radiographic sacroiliitis. Fourteen patients fulfilled the mNY criteria based on CR. Classification according to the modified New York criteria would be justified for eight patients if it was based on MRI for structural changes only, for 14 if it was based on structural changes on CR, for 14 (partly) different patients if it was based on inflammation on MRI only, for 16 if it was based on inflammation and structural changes on MRI, for 19 if it was based on inflammation on CR combined with MRI, and for (the same) 19 if it was based on inflammation and structural damage on CR combined with MRI.
  
  
  CONCLUSIONS
  CR can detect structural changes in SI joints with higher sensitivity than MRI. However, inflammation on MRI can be found in a substantial proportion of patients with IBP but normal radiographs. Assessment of structural changes by CR followed by assessment of inflammation on MRI in patients with negative findings gives the highest returns for detecting involvement of the SI joints by imaging in patients with recent onset IBP.
authors.affiliation: Department of Internal Medicine, Division of Rheumatology, University Hospital Maastricht, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Heuft-Dorenbosch
authors.forename: R
authors.initials: R
authors.lastname: Landewé
authors.forename: R
authors.initials: R
authors.lastname: Weijers
authors.forename: A
authors.initials: A
authors.lastname: Wanders
authors.forename: H
authors.initials: H
authors.lastname: Houben
authors.forename: S
authors.initials: S
authors.lastname: van der Linden
authors.forename: D
authors.initials: D
authors.lastname: van der Heijde
mesh_terms: D000328:Adult; D001168:Arthritis / Q000000981:diagnostic imaging / Q000276:immunology / Q000473:pathology*; D001416:Back Pain / Q000209:etiology* / Q000276:immunology; D005260:Female; D049669:History, 16th Century; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015588:Observer Variation; D011237:Predictive Value of Tests; D011859:Radiography; D012446:Sacroiliac Joint / Q000000981:diagnostic imaging / Q000276:immunology / Q000473:pathology*; D013167:Spondylitis, Ankylosing / Q000000981:diagnostic imaging / Q000276:immunology / Q000473:pathology