Power Doppler Sonography, a Non-invasive Method of Assessment of the Synovial Inflammation in Patients with Early Rheumatoid Arthritis

Objective: To detect synovitis is important in both the diagnosis and outcome assessment of early rheumatoid arthritis. This study was meant to assess the validity and reproducibility of ultrasonography (US) as a mean of detection for the knee synovitis, by comparing US findings with clinical examination and histopathological findings in synovial membrane.

Methods: The study group included 65 patients with early rheumatoid arthritis - below 12 months from the debut, naive for DMARDs, in whom demographic data - gender, age, disease duration, the number of tender and swollen joints, HAQ score (Health Assessment Questionnaire) and serum samples for CRP, RF, anti-CCP2 antibodies (ELISA, QUANTA LiteTM, CCP IgG, INOVA Diagnostics Inc, USA), VEGF (ELISA, VEGF2, DRG International, IRC, USA) determination were recorded. Disease Activity Score for 28 joints (DAS28) was calculated. PDS signal was scored from 0 to 3 according to the overall expression of PDS findings at the knees. A sample of synovial tissue was obtained in 35 patients during the arthroscopy, and the vascularisation of the synovial tissue was evaluated by immunohistochemistry and was analyzed qualitatively by a pathologist who was unaware of the PDS findings. Written, informed consent was obtained from each patient before entering the study. They all had active synovitis of the knee, ultrasonographically confirmed, with the identification of the target biopsy sites. The study was approved by the Ethics Committee of the University of Medicine and Pharmacy of Craiova.

Results: Angiogenesis was evaluated and quantified by immunohistochemical evaluation of synovial VEGF, one of the most specific endothelial growing factors, that proved to correlate significantly with the serum levels of VEGF, DAS28 as well as with the power Doppler sonography (PDS) score.

Conclusions: The statistical analysis of the data showed that PDS could be used as non-invasive marker with predictive value regarding synovial inflammation and disease progression in early forms of the disease as well as a useful method in the assessment of the therapeutic response.