BETWEEN-GROUP DIFFERENCES IN ULTRASONOGRAPHIC MEASURES OF SYNOVITIS AND KINETICS OF RESPONSE TO ORAL STEROIDS IN ACTIVE RA

Background: Previous studies from the Kennedy Institute of Rheumatology indicate that ultrasonographic measures of synovial thickness and vascularity can distinguish between treatment groups with greater sensitivity than clinical scores(1).Objectives: The current study was designed to:1) Compare synovial thickness and vascularity scores in RA patients across a range of disease activities; inactive to mild, and moderate to severe.2) Assess the kinetics of change in quantitative power Doppler in the severe group following a course of oral prednisolone over a two week period.Methods: Following appropriate ethical approval and informed consent, 13 patients were recruited with inactive (DAS 2.4 ± 0.8 (Baseline Mean ± SD)), 12 with moderate/severe (DAS 5.1 ± 1.2) and 11 with any activity meriting an initiation of or increase in corticosteroid treatment (DAS 5.7 ± 0.9). These patients took oral 7.5mg prednisolone daily for 14 days in addition to their normal medications.Grey-scale ultrasound was used to assess baseline synovial thickness and power Doppler imaging was used (using the Esaote Technos MPX machine) to assess vascularity in each of the 10 MCP joints by a 6-point semi-quantitative scale (range 0-5). The total synovial thickness and vascularity score for each patient was calculated as the sum of the individual joint scores. In addition, a computerised image analysis programme was used to measure the number of colour pixels in a region of interest in each individual MCP joint and the pixel count in all 10 MCP joints was summed to give the quantitative power Doppler Area (PDA).Data is presented as geometric means with lower and upper 95% CI. In the severe activity group, the Wilcoxon signed rank test was used to assess change from baseline in PDA at Day 8 and Day 15. Relationships between baseline DAS28 and PDA in all patients was assessed by Spearman correlation coefficients.Results: At baseline, indices of synovial thickness were directly proportional to baseline disease activity: corticosteroid group 17.4 (14.1; 21.4); moderate/severe group 11.8 (8.9; 15.5); inactive/mild group 8.0 (5.5; 11.5). Similarly, baseline synovial vascularity indices reflected DAS28: corticosteroid group 20.3 (16.0; 25.7); moderate/severe group 8.5 (4.8; 15.0) and inactive/mild group 8.3 (5.7; 12.2). In the whole RA cohort of 36 patients, baseline PDA correlated with DAS28 (r = 0.52 p <0.05).Baseline PDA in the corticosteroid group was 23,782 (14,990; 37,730). After 7 days of oral prednisolone, there was a significant reduction in geometric mean PDA (12,378 (5,240; 29240); p<0.05) and after 14 days it reduced further to (10,769 (4,538; 25,559); p<0.05).Conclusion: Baseline grey-scale synovial thickness and PD vascularity indices are directly proportional to DAS28 scores.Quantitative power Doppler signal (PDA) in the MCP joints was significantly reduced within one week of oral prednisolone suggesting that the rapid kinetics of change in PDA may have value as an early objective marker of therapeutic response.References: 1. Taylor PC, Steuer A, Gruber J, et al (2004) Comparison of ultrasonographic assessment of synovitis and joint vascularity with radiographic evaluation in a randomized, placebo-controlled study of infliximab therapy in early rheumatoid arthritis. Arthritis Rheum 50:1107Citation: Ann Rheum Dis, volume 65, supplement II, year 2006, page 587Session: Diagnostics and imaging procedures