AB1202 Is fluorescence optical imaging assessment associated with ultrasonography synovitis in the wrist and hand of rheumatoid arthritis patients?
Authors: M.A. Danielsen, M. Østergaard, L. Terselv, D. Glinatsi
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Fluorescence optical imaging (FOI) has been used for assessment of inflammation (i.e. synovitis) in the hands and has in several cross sectional studies been compared with ultrasonography (US) and magnetic resonance imaging (MRI), using different, but not validated scoring systems. <h3>Objectives</h3> The primary objective was to examine the association between FOI and US for assessment of synovitis in the rheumatoid arthritis (RA) hands, in a longitudinal study, using a new validated and clinically feasible FOI scoring system. <h3>Methods</h3> 46 RA patients, eligible for induction or intensification of conventional synthetic or biological disease modifying anti-rheumatic drugs and with ≥1 clinically swollen joint in the hand, were included. FOI image-sets of both wrists and hands were obtained at baseline and 6 months' follow-up using a Xiralite system unit (nanoPET Pharma GmbH, Berlin, Germany). The patients received a bolus of i.v. indocyanine green (ICG) pulsion 10 s after starting the examination, which obtained 1 image/second for 6 min. All FOI images were scored by two readers for synovitis at the wrist, 1st-5th metacarpophalangeal, 1st interphalangeal and 2nd-4th proximal interphalangeal joint levels in both hands, using the novel semiquantitative scoring system. Each joint was scored 0–3 (range 0–66) for synovitis. The readers were blinded to patient data, but not chronology and had previously showed a high intra- and inter-reader agreement (intra-class correlation coefficient (ICC):0.70–0.92). For ultrasound assessment, a GE Logiq E9 US unit with a high frequency linear 6–15 ML probe and with Doppler settings according to published recommendations was used. Synovitis was scored from 0–3 for grey scale (GS) and Doppler (DP) using the OMERACT US synovitis scoring system by two trained assessors who had previously demonstrated high intra- and inter-reader agreement (wKappa;0.88–0.95). DAS28-CRP and swollen joint count (SJC) in the hand were assessed at both time points. Descriptive statistics and the Wilcoxon signed-rank test were used to assess change in score over time. Agreement for status and change scores were assessed using single measure ICCs and spearman's correlation (SP). Responsiveness was assessed using standardised response mean (SRM). <h3>Results</h3> Median (IQR) total score at baseline was FOI 11.0 (6;19), GS 14.5 (8;22.), DP 8 (3;14), DAS28 5 (4.4;5.4) and SJC 6 (3;8) and improved with −7.8 (-13;−3.5) −9 (−15;−3.5),–5.5 (-11;−0.5), −2(−2.9;- 0.8) and −4(−7;−2) at 6 months' follow up, respectively (p&lt;0.01). Figure 1 presents the change score and a trend line based on 4 patients' average score. ICC and SP between FOI and US (GS and DP) total scores were low for both readers at baseline (range 0.3–0–4) (p&lt;0.05), and low to moderate (range 0.31–0.54) (p&lt;0.01) for change scores. The mean SRM for total change scores between baseline and 6 months' follow-up were good for all parameters (FOI:0.9, GS:1.0, DP:0.8, DAS28:0.9 and SJC:1.0). The average time required to score one patient was 140 s. <h3>Conclusions</h3> This study shows a significant correlation and corresponding trendlines between FOI and US for change over time, and good responsiveness using the new FOI scoring system. FOI may therefore be used as an alternative to known imaging modalities for monitoring RA patients in clinical trials, and potentially in the daily clinical practice. <h3>Disclosure of Interest</h3> None declared