Novel Ultrasound Image Acquisition Protocol and Scoring System for the Pediatric Knee

The use of musculoskeletal ultrasound is increasing among pediatric rheumatologists. Reliable scoring systems are needed for the objective assessment of synovitis. The aims of this study were to create a standardized and reproducible image acquisition protocol for B-mode and Doppler ultrasound of the pediatric knee, and to develop a standardized scoring system and determine its reliability for pediatric knee synovitis.

Six pediatric rheumatologists developed a set of standard views for knee assessment in children with juvenile arthritis. Subsequently, a comprehensive literature review, practical exercises, and a consensus process were performed. A scoring system for both B-mode and Doppler was then developed and assessed for reliability. Interreader reliability or agreement among a total of 16 raters was determined using 2-way single-score intraclass correlation coefficient (ICC) analysis.

Twenty-one views to assess knee arthritis were initially identified. Following completion of practical exercises and subsequent consensus processes, 3 views in both B-mode and Doppler were selected: suprapatellar longitudinal and medial/lateral parapatellar transverse views. Several rounds of scoring and modifications resulted in a final ICC of suprapatellar view B-mode 0.89 (95% confidence interval [95% CI] 0.86-0.92) and Doppler 0.55 (95% CI 0.41-0.69), medial parapatellar view B-mode 0.76 (95% CI 0.68-0.83) and Doppler 0.75 (95% CI 0.66-0.83), and lateral parapatellar view B-mode 0.82 (95% CI 0.75-0.88) and Doppler 0.76 (95% CI 0.66-0.84).

A novel B-mode and Doppler image acquisition and scoring system for assessing synovitis in the pediatric knee was successfully developed through practical exercises and a consensus process. Study results demonstrate overall good-to-excellent reliability.