ARTHRITIS IN SYSTEMIC LUPUS ERYTHEMATOSUS: AN IMAGING POINT OF VIEW

Background. Arthritis in SLE is a frequent manifestation which can range from mild synovitis to severe erosive form. In rheumatoid arthritis, new musculoskeletal imaging tech- niques (US and MRI) have demonstrated high sensitivity in detecting early inflammatory and structural abnormalities. We hypothesized that a complete imaging evaluation integrating conventional radiography, US as well as MRI findings could allow a more accurate characterization of joint involvement in SLE permitting an earlier identification of patients at risk of longterm progression to deforming arthritis Aim. To study hand and wrist joints in a cohort of consecutive SLE patients and to compare US and MRI performances. Methods. 50 patients (45 female, mean age 39.8±14, mean disease duration 14.3±8) and 28 sex and age- matched healthy controls were enrolled. Assessment included a complete joint evaluation, autoantibodies determination, hand-wrist US with power Doppler (with a linear probe operating at 14 MHz) and MRI (with a 0.2 Tesla dedicated-extremity unit) without con- trast. Joint effusion (JE), bone erosion (BE) and edema (BED) were recorded and scored according to the RAMRIS scoring systems for RA. We decided not to include the gadolinium- containing contrast injection in our protocol because of the high prevalence of renal involvement in SLE patients (60%) in order to avoid possible gadolinum-related nephrotoxicity. Con- sidering the possible presence of BE also in healthy controls, we analyzed our controls to set-up an arbitrarily defined threshold of 5 to distinguish clinically significant erosive burden in our patients from aspecific bone lesions. Results. 20 (40%) SLE patients reported a history of clinically severe arthritis conditioning chronic pain and continuative ther- apy and 14 (28%) showed clinical signs of hand-wrist arthritis at enrolment. US examination revealed pathological findings in 23 patients (46%) showing hand and/or wrist arthritis in 12 and 11 respectively while tenosynovitis was recorded in 17 cases (34%). Synovial hypertrophy was detected in 27% of cases with positive power Doppler signal in 14%, and BE were found in 18% of cases. At MRI, pathological BE were detected in 63% of patients with arthritis (mainly at wrist) with con- comitant BED or effusion in 13%. The mean erosive burden resulted significantly higher in patients than in controls (8.95 vs 5.05. p