Ultrasound in rheumatoid arthritis - volar versus dorsal synovitis evaluation and scoring

BACKGROUND: Assessment of synovitis in Rheumatoid Arthritis (RA) is a major issue for a proper treatment administration; it has been proven that ultrasound (US) examination could be of valuable help and it is currently being investigated as a possible outcome measure for the disease. It is, though, of greatest importance to accurately establish the place of US scores among the already validated outcome measures, according to Outcome Measures for Rheumatoid Arthritis in Clinical Trials (OMERACT) filter. The present study is designed to compare the results of gray-scale ultrasound (GSUS) and Power Doppler ultrasound (PDUS) additive scores, separately calculated for volar and dorsal aspects of the hand, with physical examination, patient's evaluation of disease pain and global activity on Visual Analogic Scale (VAS) and traditional scores for disease activity assessment (DAS28, CDAI, SDAI, HAQ). The final aim is to prove the advantages of volar US evaluation in RA patients. METHODS: 42 RA patients have been clinically evaluated for pain and swelling of their hand joints, completed VAS and HAQ questionnaires and underwent both volar and dorsal sonography of the hands during the same day. The US examiner was blinded to clinical assessments and lab results. For each patient 20 joints were assessed by sonography (radiocarpal, intercarpal, metacarpophalangeal (MCP) 2-5, proximal interphalangeal (PIP) 2-5). Carpal joints were only evaluated from dorsal view, while MCPs and PIPs were evaluated both from dorsal and volar aspect resulting a total of 36 distinct evaluations for each patient. GSUS synovial hypertrophy was assessed both by quantitative measurement and semiquantitative scale (0-3 grades); Doppler signal (PDUS) was recorded on a semiquantitative scale (0-3 grades). The semiquantitative grades for both GSUS and PDUS evaluation of each joint were added and the sum was defined as the Echographic Score (ES) of each patient. Separately, we added the semiquantitative grades for volar and dorsal side, resulting in Volar ES (VES) and Dorsal ES (DES) of each patient. RESULTS: We found ESs correlated with other activity scores: DAS28, CDAI, SDAI, HAQ. Correlations with clinical indices as CDAI and SDAI were stronger for VES than for DES. US discovered more synovitis than clinical examination. CONCLUSION: VES is a suitable reflection of RA activity and volar US examination should accompany the dorsal one both in clinical practice and in clinical trials.