ABSTRACT
OBJECTIVE: To develop definitions for the assessment of magnetic resonance imaging (MRI) pathologies of the sacroiliac joints (SIJ) in juvenile idiopathic arthritis. METHODS: An Outcome Measures in Rheumatology (OMERACT) consensus-driven methodology consisting of iterative surveys and focus group meetings within an international group of rheumatologists and radiologists. RESULTS: Two domains, inflammation and structural, were identified. Definitions for bone marrow edema, joint space inflammation, capsulitis, and enthesitis were derived for joint inflammation; sclerosis, erosion, fatty lesion, and ankylosis were defined for assessing structural joint changes. CONCLUSION: Preliminary consensus-driven definitions for inflammation and structural elements have been derived, underpinning the ongoing development of the OMERACT Juvenile Arthritis MRI SIJ scoring system (OMERACT JAMRIS-SIJ).