AB1131 HIGH-RESOLUTION ULTRASOUND ASSESSMENT OF CARTILAGE THINNING IN RHEUMATOID ARTHRITIS

Abstract

Background Conventional radiography is the standard imaging modality to detect joint damage in rheumatoid arthritis (RA). Ultrasound (US) allows for a direct visualization of hyaline cartilage. To date, only few studies investigated the role of US in the assessment of cartilage damage in RA. Objectives To compare US qualitative and quantitative assessments of cartilage thinning at metacarpal head (MH) in RA patients and in an age-, sex- and height-matched healthy controls (H). To correlate cartilage damage and clinical parameters in RA. Methods US examination was performed on 318 metacarpophalangeal (MCP) joints of 40 consecutive RA patients and on 320 MCP joints of 40 age-, height- and sex-matched H using a MyLab Twice (Esaote Biomedica, Genoa, Italy), equipped with a high frequency linear probe (up to 22 MHz). RA patients were enrolled according to the 2010 RA classification criteria. The hyaline cartilage of MH from II to V digits of both hands was examined with the MCP joints in maximal flexion. Each MH was scanned in longitudinal and transverse views. Particular attention was paid on maintaining the probe in a position providing an angle of 90° between the direction of the US beam and the cartilage surface1. Cartilage thickness (CT) was assessed both semi-quantitatively (using a reliable qualitative five-grade scoring system2) and quantitatively (using the mean value of longitudinal and transverse measurements of the CT). Finally, association between cartilage damage and clinical parameters was assessed. Results Semiquantitative score Cartilage thinning (grade 2, 3 and 4) was found in at least one MH in 23 RA patients (57.5%) and in 4 H (10.0%) (p Quantitative assessment CT of the MH ranged from 0.0 to 1.10 mm (0.60±0.26 mm, mean±SD) in RA patients and from 0.41 to 1.08 mm (0.67±0.12 mm, mean±SD) in H. Male had a thicker hyaline cartilage than female, both in RA patients (p Detailed quantitative measurements of CT of MH are reported in table 2. 95%CI: 95% confidence interval; L: left; MH: metacarpal head; R: right; RA: rheumatoid arthritis; SD: standard deviation; US: ultrasound. A significant association was found between the CT value and age (r=-0.528, p Conclusion This study demonstrated that a significantly higher prevalence of cartilage damage was found in RA patients using both the semiquantitative score and the quantitative assessment. In particular, in RA patients the hyaline cartilage of II and III MH is thinner in comparison with H. Finally, a significant association was found between the CT values and disease duration and age.