We retrospectively evaluated 194 patients with arthritis. All patients underwent joint sonography, power Doppler ultrasound, synovial fluid analysis and blood examination of C-reactive protein and erythrocyte sedimentation rate. Correlation analyses (Spearman and Pearson), Chi2 test, t-tests, a unifactorial ANOVA and regression analyses were applied.
Hypervascularisation in power Doppler was most prominent in gout and calcium pyrophosphate deposition disease. Spondyloarthritis and non-inflammatory joint diseases presented with low degrees of hypervascularisation. Mean synovial white blood count did not differ significantly between crystal-related arthritides, rheumatoid arthritis, spondyloarthritis or other inflammatory joint diseases. There was a positive but weak correlation between power Doppler signals and synovial white blood count (P < 0.001, rs = 0.283), erythrocyte sedimentation rate (P < 0.001, rs = 0.387) and C-reactive protein (P < 0.001, rs = 0.373) over all diagnoses. This was especially relevant in rheumatoid arthritis (P < 0.01, rs = 0.479). Power Doppler degrees 0 and 1 were able to predict synovial leukocytes < 5/nL, degrees 2 and 3 predict leukocytes ≥ 5/nL (P < 0.001).