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SAT0223 The Diagnostic Utility of Fluorescence Optical Imaging in Evaluating Synovitis of the Hands and Wrists
  1. N. Győri1,
  2. Y. Kisten1,
  3. H. Rezaei1,
  4. A. Karlsson2,
  5. C. Romanus2,
  6. E. af Klint2,
  7. R. van Vollenhoven1
  1. 1ClinTRID, Clinical Therapy Research, Inflammatory Diseases, Department of Medicine
  2. 2Rheumatology Clinic at the Karolinska University Hospital, Karolinska Institute, Stockholm, Sweden

Abstract

Background The timely identification of synovial inflammation is critical for early diagnosis & treatment of rheumatoid arthritis & other inflammatory arthritides. Fluorescence Optical Imaging (FOI, “Rheumascan”), a novel imaging modality, uses an intravenous fluorescence dye, that enables imaging of the hands & wrists with increased optical intensities in areas of high perfusion &/or capillary leakage.

Objectives To determine the sensitivity & specificity of FOI as a diagnostic tool in determining “active” synovitis as compared to the US & clinical findings.

Methods A total of 748 joints of both hands & wrists, including 3 wrist joints, 5 MCPs, 5 PIPs, & 4 DIPs in 22 patients (15 female, 7 male) with an age average of 44yrs old, with inflammatory arthritis (RA: 9; JIA, psoriatic arthritis, SLE, polyarthritis & other diagnoses, 1-2 each) were examined clinically, by US & FOI. Only swollen & tender joints were regarded as clinically inflamed. Positive colour Doppler US signals with synovial thickening/fluid were considered as “active” synovitis. FOI was scored visually. Comparisons were done using kappa statistics, and the diagnostic utility (sensitivity & specificity) of FOI was tested.

Results 72 out of 748 joints (10%) were considered inflamed by clinical examination, 144 (19%) by US, and 129 (17%) by FOI. Of the clinically inflamed joints, 49 (68%) were identified as “actively” inflamed by ultrasound, and 37 out of 72 (51%) of these joints were inflamed by FOI. Out of 676 joints that were negative by clinical examination, 581 (86%) were negative by ultrasound and 575 (95%) by FOI. The agreement between clinical examination & US was fair (kappa 0.37±0.05) and somewhat stronger than the agreement between clinical examination & FOI (kappa 0.28±0.05). Out of 144 joints that were “actively” inflamed by US, 100 (69%) showed inflammation by FOI, while out of 604 non-inflamed joints by US, 575 (95%) were non-inflamed by FOI. The agreement between US and FOI was good (kappa 0.67±0.04). Out of 49 joints that were inflamed both by clinical examination & by US, 27 (55%) were inflamed by FOI.

Conclusions The sensitivity of FOI for inflammation in individual joints of the hands & wrists were 51-76% depending on what “gold standard” was used to define inflammation. The specificity of FOI was 95% (575/604), suggesting that it has lower sensitivity but similar specificity compared to US. These findings, together with good agreement between US & FOI, suggest that the latter may be used as a complementary diagnostic tool in clinical practice, in particular when US is not available, in order to identify synovitis earlier and with greater confidence.

Acknowledgements To the patients & all involved in this study in one way or the other.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.2484

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