AB1024 Clinically “Silent” Synovitis: Detected by Fluorescence Optical Imaging of the Hands &amp; Wrists
Authors: Y. Kisten, N. Györi, H. Rezaei, A. Karlsson, C. Romanus, E. af Klint, R. van Vollenhoven
Journal: Annals of the Rheumatic Diseases (2014)

<h3>Background</h3> The detection of sub-clinical synovial inflammation ("silent synovitis") would be of critical importance for the detection of rheumatoid arthritis (RA) &amp; other inflammatory arthritides, in its earliest pathophysiological stage ("pre-RA"). It has been suggested that ultrasound (US) with power or colour Doppler, can be a useful technology to achieve this. Ultrasound however, requires specially trained/skilled operators. Fluorescence optical imaging (FOI, "Rheumascan") is a novel imaging modality based on the use of an intravenous fluorescence dye, that allows imaging of the hands &amp; wrists, with increased focal optical signal intensities in areas of high perfusion &amp;/or capillary leakage. This diagnostic tool, is operator independent, &amp; can be well carried out by a rheumatology nurse. <h3>Objectives</h3> Here, we investigated whether FOI (Rheumascan) could be used in lieu of US (colour Doppler) for ascertaining hand &amp; wrist sub-clinical synovitis. <h3>Methods</h3> A total of 748 hand &amp; wrist joints (6 wrist, 10 MCPs, 10 PIPs &amp; 8 DIPs) in 22 patients (7 male &amp; 15 female), aged between 19 &amp; 84 years, with inflammatory arthritis (RA:9, JIA, polyarthritis, psoriatic arthritis, SLE &amp; other diagnoses, 1-2 each) were examined clinically, by US &amp; FOI. Joints were considered clinically inflamed when both swollen and tender, &amp; non-inflamed otherwise. Ultrasound was considered positive for "active" synovitis if both thickening on grey scale &amp; Doppler signals were present. FOI was considered positive in joints that displayed focal signal intensities, by visual inspection of recorded images &amp; video clips. <h3>Results</h3> Out of 748 joints evaluated, 72 (10%) were considered inflamed by clinical examination and 676 (90%) were not. Of the clinically non-inflamed joints, exactly 95 (14%) were inflamed by US. Of these joints, 72 (76%) were inflamed by FOI and 23 (24%) were not. Thus, the sensitivity of FOI for detecting clinically "silent" synovitis when defined as a positive US in the absence of clinical inflammation was 76%. Out of the 581 joints that were non-inflamed clinically and non-inflamed by ultrasound, 24 (4%) had inflammation by FOI, yielding a specificity of 96% (557/581). <h3>Conclusions</h3> Under the assumption that US can correctly identify sub-clinical synovitis in clinically non-inflamed joints (using the combination of clinical examination &amp; US as the "gold standard"), the sensitivity of FOI for detecting clinically "silent synovitis" in the hands &amp; wrists is 76% and the specificity 95%. These metrics suggest that it may be a useful diagnostic tool in the setting of identifying patients with very early synovial inflammation of the hands &amp;/or wrists. <h3>Acknowledgements</h3> To all the patients &amp; participants of the study. <h3>Disclosure of Interest</h3> None declared <h3>DOI</h3> 10.1136/annrheumdis-2014-eular.2215