title: Comparison of ultrasonography and magnetic resonance imaging for the assessment of clinically defined knee enthesitis in spondyloarthritis.
abstract: OBJECTIVE
  Ultrasonography (US) and magnetic resonance imaging (MRI) are increasingly used imaging techniques for visualising entheses, however few studies have made a direct comparison of each. This study aimed to compare each technique for the detection of enthesitis in patients with spondyloarthritis (SpA) related knee swelling in order to make a lesion by lesion comparison.
  
  
  METHODS
  Consecutive SpA patients with knee synovitis were recruited: each had clinical assessment for enthesitis at 8 sites in the involved knee joint followed by US and MRI examinations. Inflammatory and structural changes at tendon and ligament insertions were scored and a lesion by lesion comparison was made.
  
  
  RESULTS
  21 patients were recruited. Clinically defined involved knee joint enthesitis was evident in 18 of 21 (86%) patients in 61 of 168 (36%) evaluated sites. Clinical enthesitis was associated with more hypoechogenicity (16 vs. 4%, p=0.007) and thickening (16 vs. 6%, p=0.03) by US compared to non-tender sites. Considering all MRI findings only increased signal in the surrounding tissues was higher at tender sites (41 vs. 20%, p=0.01) and the insertions points themselves showed little abnormality. The positive agreements between individual lesions by both methods was very low (10-26%) with low kappa values (0.06-0.18) with no correlations between the MRI and US scores (r²= 0.059).
  
  
  CONCLUSIONS
  The difficulty in procuring 'gold standard' histological validation is synovial joints makes the assessment of enthesitis using clinical and current imaging protocols of limited utility for diagnostic purposes.
authors: Istanbul Medeniyet University, Goztepe Training and Research Hospital, Rheumatology Unit, Istanbul, Turkey. drsibelaydin@gmail.com.
authors: Sibel Zehra
authors: SZ
authors: Aydin
authors: Ai Lyn
authors: AL
authors: Tan
authors: Richard
authors: R
authors: Hodsgon
authors: Andrew
authors: A
authors: Grainger
authors: Paul
authors: P
authors: Emery
authors: Richard J
authors: RJ
authors: Wakefield
authors: Dennis
authors: D
authors: McGonagle
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000473:pathology*; D008023:Ligaments, Articular / Q000000981:diagnostic imaging / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010808:Physical Examination; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D025241:Spondylarthritis / Q000000981:diagnostic imaging* / Q000473:pathology*; D013585:Synovitis / Q000000981:diagnostic imaging / Q000473:pathology; D013710:Tendons / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography; D055815:Young Adult
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA