title: Diagnostic value of pelvic enthesitis on MRI of the sacroiliac joints in spondyloarthritis.
abstract: OBJECTIVE
  To determine the prevalence and diagnostic value of pelvic enthesitis on MRI of the sacroiliac (SI) joints in spondyloarthritis (SpA).
  
  
  METHODS
  A retrospective study in 444 patients aged 17-45 years old with MRI of the SI joints and with clinically suspected sacroiliitis was performed. Patients were classified as having SpA if they fulfilled the Assessment of Spondyloarthritis International Society (ASAS) criteria. Pelvic enthesitis on MRI was correlated with the final diagnosis. Sensitivity, specificity, positive and negative likelihood ratio (LR) and predictive values (PV) of pelvic enthesitis for the diagnosis of SpA were calculated.
  
  
  RESULTS
  MRI showed pelvic enthesitis in 24.4 % of patients with SpA and in 7.1 % of patients without SpA. Presence of any enthesitis had sensitivity, specificity, LR+, LR-, PPV and NPV of 24.4 %, 92.9 %, 3.45, 0.81, 69.4 % and 65.2 % for the diagnosis of SpA, respectively. The most commonly affected entheses were the longitudinal ligament insertion (4.5 %), the retroarticular ligaments (4.1 %) and the pubic symphysis (4.1 %). The sites of enthesitis with the highest PPV for SpA were the iliac crest/wing (85.7 %) and the retroarticular ligaments (81.3 %).
  
  
  CONCLUSIONS
  Nearly one fourth of SpA patients with suspected sacroiliitis showed pelvic enthesitis on MRI. Such pelvic enthesitis has a high specificity for the diagnosis of spondyloarthritis.
  
  
  CONCLUSIONS
  • Enthesitis is the primary clinical feature of spondyloarthritis. • Magnetic resonance imaging of the sacroiliac joints can demonstrate pelvic enthesitis. • Pelvic enthesitis has a high specificity for the diagnosis of spondyloarthritis.
authors.affiliation: Department of Radiology and Medical Imaging, Ghent University Hospital, De Pintelaan 185, 9000, Gent, Belgium, lennartjans@hotmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Jans
authors.forename: C
authors.initials: C
authors.lastname: van Langenhove
authors.forename: L
authors.initials: L
authors.lastname: Van Praet
authors.forename: P
authors.initials: P
authors.lastname: Carron
authors.forename: D
authors.initials: D
authors.lastname: Elewaut
authors.forename: F
authors.initials: F
authors.lastname: Van Den Bosch
authors.forename: V
authors.initials: V
authors.lastname: Lambrecht
authors.forename: J L
authors.initials: JL
authors.lastname: Jaremko
authors.forename: K
authors.initials: K
authors.lastname: Verstraete
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011631:Pubic Symphysis / Q000473:pathology; D012189:Retrospective Studies; D012446:Sacroiliac Joint / Q000473:pathology*; D058566:Sacroiliitis / Q000473:pathology*; D012680:Sensitivity and Specificity; D025241:Spondylarthritis / Q000175:diagnosis*; D052256:Tendinopathy / Q000473:pathology