How useful is contrast-enhanced ultrasound in rheumatoid arthritis? A systematic review with meta-analysis on the comparison between contrast-enhanced ultrasound and colour or power Doppler ultrasound

Objective: The primary objective was to evaluate the additional benefits of contrast-enhanced ultrasound (CEUS) compared to unenhanced Doppler ultrasound (DUS) for the identification of active synovitis in rheumatoid arthritis (RA). Methods: We searched PubMed/MEDLINE and EMBASE (February 2024) for all English-written published reports of human studies including the use of CEUS for the study of synovitis in RA. The risk of bias of included studies was evaluated using the QUADAS tool. DUS and CEUS semiquantitative scores were transformed in binomial, and these data were extracted for meta-analysis. Results that we were unable to quantitatively aggregate were summarised qualitatively. Results: Twenty-three studies using CEUS to evaluate 1117 joints from 827 subjects were included, of which 898 joints were from 669 RA patients. We performed a meta-analysis of 9 studies in active RA patients showing that from 474 joints evaluated by either PDUS/CDUS and CEUS, the synovitis detection was 49.2% and 83.8%, respectively, corresponding to a relative detection ratio (RDR) of 1.49 (95% CI 1.23–1.81) favouring CEUS. Heterogeneity of the data was moderate. In healthy subjects, CEUS detected no vascularisation in 4 studies. Discussion: CEUS detects more microvascularisation than PDUS in active RA with an RDR of 1.49.