title: Reliability and construct validity of ultrasonography of soft tissue and destructive changes in erosive osteoarthritis of the interphalangeal finger joints: a comparison with MRI.
abstract: OBJECTIVE
  To study the reliability and construct validity of ultrasound in interphalangeal finger joints affected by erosive osteoarthritis (EOA) and non-EOA with MRI as the reference method.
  
  
  METHODS
  252 joints were examined by ultrasound, conventional radiography and clinical examination. Ultrasound was performed using a high-frequency linear transducer (12 × 18 MHz). On the same day, magnetic resonance images of 112 joints were obtained on a 3.0 T magnetic resonance unit. The ultrasound and MRI images were re-read independently by other readers unaware of the diagnosis, clinical and other imaging findings. Interobserver reliability was calculated by the percentage of exact agreement obtained and κ statistics. With MRI as the reference method, the sensitivity and specificity of ultrasound in detecting structural (bone erosions and osteophytes) and soft tissue (effusion and grey-scale synovitis) changes in EOA were calculated.
  
  
  RESULTS
  Ultrasound and MRI were found to be more sensitive in detecting erosions than conventional radiography in EOA. A high agreement between ultrasound and MRI in the assessment of bone erosions (77.7%), osteophytes (75.9%) and synovitis (86.5%) was present. A high percentage of inflammatory changes was found in EOA, and in smaller amount in non-EOA, both confirmed by MRI. Good interobserver reliability of ultrasound was obtained for all variables (all median κ > 0.8).
  
  
  CONCLUSIONS
  Grey-scale ultrasound proved to be a reliable and valid imaging technique to assess erosions and soft tissue changes, compared with MRI as a reference method in EOA.
authors.affiliation: Department of Rheumatology, University Hospital Ghent, Gent, Belgium. ruth.wittoek@ugent.be
authors.forename: Ruth
authors.initials: R
authors.lastname: Wittoek
authors.forename: Lennart
authors.initials: L
authors.lastname: Jans
authors.forename: Valérie
authors.initials: V
authors.lastname: Lambrecht
authors.forename: Philippe
authors.initials: P
authors.lastname: Carron
authors.forename: Koenraad
authors.initials: K
authors.lastname: Verstraete
authors.forename: Gust
authors.initials: G
authors.lastname: Verbruggen
mesh_terms: D000368:Aged; D005260:Female; D005384:Finger Joint / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010003:Osteoarthritis / Q000175:diagnosis / Q000000981:diagnostic imaging*; D054850:Osteophyte / Q000175:diagnosis / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013585:Synovitis / Q000175:diagnosis / Q000000981:diagnostic imaging; D014463:Ultrasonography