Associations between power Doppler ultrasound findings and B-mode synovitis and clinical arthritis in juvenile idiopathic arthritis using a standardised scanning approach and scoring system

Abstract

Objectives To describe power Doppler (PD) ultrasound findings in joint regions with B-mode (BM) synovitis using a standardised scanning protocol and scoring system in patients with juvenile idiopathic arthritis (JIA). Further, to examine associations between PD findings and BM synovitis, clinical arthritis, patient characteristics and disease activity. Methods In this cross-sectional study, one experienced ultrasonographer, blinded to clinical findings, performed ultrasound examinations in 27 JIA patients with suspected clinical arthritis. The elbow, wrist, metacarpophalangeal 2-3, proximal interphalangeal 2-3, knee, ankle and metatarsophalangeal 2-3 joints were assessed bilaterally and scored semiquantitatively (grades 0-3) for BM and PD findings using a joint-specific scoring system with reference atlas. Multilevel mixed-effects ordered regression models were used to explore associations between PD findings and BM synovitis, clinical arthritis, age, sex, JIA subgroups, disease duration and 10-joint Juvenile Arthritis Disease Activity Score (JADAS10). Results Twenty-one girls and six boys, median age (IQR) 8 years (6-12 years) were included. Overall, 971 joint regions were evaluated by ultrasound, 129 had BM synovitis and were assessed for PD. PD findings were detected in 45 joint regions (34.9%), most frequently in the parapatellar recess of the knee (24.4%). Increasing PD grades were associated with higher BM grades (OR=5.0,p<0.001) and with clinical arthritis (OR=7.4,p<0.001) but not with age, sex, JIA subgroups, disease duration or JADAS10. Conclusion Increasing severity of PD findings were significantly associated with BM synovitis and with clinical arthritis. This suggests that PD signals detected using a standardised ultrasound examination and scoring system can reflect active disease in JIA patients.