Decrease of synovial power Doppler flow in arthritis patients under therapy with the TNF-alpha inhibitor adalimumab

Objectives: Power Doppler ultrasound (PDUS) is used to verify the efficacy of a current treatment strategy. Changes of synovial perfusion in arthritic joints are evaluated using quantitative three-dimensional (3D) power Doppler analyses (voxel count) under anti-inflammatory treatment with adalimumab in arthritis patients.

Methods: Inflamed joints of 24 patients with active arthritis were examined by two independent ultrasound investigators during 4 follow up visits under initiation of treatment with the TNF-alpha inhibitor adalimumab. US was performed with a HDI 5000 (ATL/Philips, Bothell, WA/USA) using a linear array transducer (L12–5/38mm, 5 to 12MHz). Besides clinical and laboratory assessment of disease activity parameters, three-dimensional (3D) power Doppler sonographic movies of synovial vascularity were obtained to calculate the amount of volume pixels (voxels) for the quantification of synovial microvascular Doppler flow.

Results: The number of voxels decreased significantly at week 6 (-38%; p<0.01) and substantially after three months (-70%, p<0.001, Wilcoxon's rank sum test). The amount of power Doppler voxels correlated with the disease activity score (DAS 28; p<0.001, r=0.35, Spearman's rank test), the C-reactive protein (CRP; p<0.001, r=0.29) and the Health Assessment Questionnaire (HAQ; p<0.01, r=0.3). Interobserver agreement was r=0.80 (Pearson's correlation coefficient).

Conclusions: PDUS including 3D imaging provides a valuable tool for the measurement of arthritic activity in clinical trials with the voxel count as a new quantification method of synovial blood flow.