A novel magnetic resonance imaging (MRI)-based, semi-objective scoring system developed for use in children with suspected juvenile dermatomyositis (JDM), the JDM Image Score, is a reliable standardized tool for assessing the degree of muscle inflammation in children with suspected JDM, according to the results of an analysis published in Rheumatology.
The investigators sought to evaluate the reliability of the JDM Image Score for reporting the severity of MRI findings in patients with suspected JDM. The JDM Image Score is based on the severity, extent, and volume of muscle inflammation, as well as the presence of muscle and perifascicular edema. A panel of 9 consultant pediatric radiologists independently assessed and scored 40 axial and 30 coronal thigh MRIs of children with potential JDM on 2 separate occasions using the JDM Image Score.
The score was calculated for both readings for each plane and each limb, with scores ranging from 0 (normal) to 100 (severe). Inter- and intra-observer agreement was computed using the intraclass correlation coefficient (ICC).
The overall inter-observer reliability and agreement was good: for axial images, the JDM Image Score ranged from 46.8 to 61.0 (ICC, 0.88; 95% CI, 0.82-0.92) for the left limb and from 47.9 to 61.4 (ICC, 0.87; 95% CI, 0.81-0.92) for the right limb. For coronal images, the JDM Image Score ranged from 56.7 to 65.1 (ICC, 0.90; 95% CI, 0.85-0.95) for the left limb and from 55.7 to 66.8 (ICC, 0.90; 95% CI, 0.84-0.94) for the right limb. Intraobserver reliability and agreement was also good, with ICC ranging from 0.90 to 0.94.
The investigators concluded that the JDM Image Score has the potential to serve as a semi-quantitative, semi-objective, reliable biomarker of disease activity and response to therapeutic interventions in pediatric patients with suspected JDM. In this regard, the JDM Image Score can provide a uniform platform for reporting clinical and research findings in children with JDM.
Thyoka M, Adekunle O, Pilkington C, et al. Introduction of a novel magnetic resonance imaging-based scoring system for assessing disease activity in children with juvenile dermatomyositis [published online June 12, 21018]. Rheumatology (Oxford). doi:10.1093/rheumatology/key144