Superb Microvascular Imaging in Assessment of Synovitis and Tenosynovitis in Juvenile Idiopathic Arthritis

The aim of this study is to evaluate the diagnostic utility of superb microvascular imaging (SMI) in assessment of synovitis/tenosynovitis in juvenile idiopathic arthritis in comparison to power Doppler ultrasound. Thirty juvenile idiopathic arthritis cases with active clinical findings and ultrasound features of effusion and/or tenosynovitis were further imaged with power Doppler and SMI. For classification of synovial inflammation, a semiquantitative scale (4 points) adopted by Outcome Measures in Rheumatology was used.A total of 35 knee, 2 hip, 2 ankle, 2 wrist, 2 elbow joints, and 6 flexor hallucis longus/tibialis posterior tenosynovitis were assessed. In knee joint, power Doppler and SMI scales were the same for 23 (65.7%) joints, SMI upgraded scale from 0 to 2 in single joint (2.9%); 1 to 2 (14.3%) in 5 joints; and 2 to 3 (17.1%) in 6 joints. For other joints, power Doppler and SMI scales were the same for 5 (62.5%) joints. Superb microvascular imaging upgraded scale from 1 to 2 (25%) in 2 joints and 1 to 3 (12.5%) in a single joint. For flexor hallucis longus/tibialis posterior tenosynovitis, power Doppler and SMI scales were the same for two cases (33.3%). Superb microvascular imaging upgraded scale from 0 to 2 in two cases (33.3%); and 2 to 3 (33.3%) in 2 cases. There was no case of SMI scale downgraded compared with power Doppler scale.Superb microvascular imaging is a feasible technique in the assessment of synovial inflammation and tenosynovitis in juvenile idiopathic arthritis. Superb microvascular imaging has higher sensitivity compared with power Doppler ultrasound in depiction of increased vascularity.