Purpose or Case Report: Whole body (WB) MRI is a valuable method for surveying the overall burden of systemic diseases such as juvenile idiopathic arthritis (JIA), directing further diagnostic and treatment approaches. Consensus-driven development and validation of a standardized WB-MRI scoring system for JIA has important clinical utility in timely detection and monitoring of disease activity, and serves as an outcome measure in research. We describe our experience utilizing a formal consensus approach amongst imaging and/or clinical JIA experts towards developing a novel WB MRI scoring system to assess disease activity in JIA.
Methods & Materials: Three rounds of anonymous, iterative Delphi surveys were used to determine the relevant anatomic joints for assessment, diagnostic item selection, definition and grading, and selection of appropriate imaging planes and sequences. These surveys were completed independently by an international expert group consisting of pediatric musculoskeletal radiologists and rheumatologists. The rates of agreement for potential choices, and additional suggestions were discussed amongst the group after each survey, ultimately yielding to a structured WB-MRI scoring system for JIA.
Results: Eighteen to 22 experts participated in three rounds of Delphi surveys and a concluding consensus meeting. A first iteration scoring system was developed that ultimately included assessment of 40 joints, representation of both axial and peripheral joints, 2-5 diagnostic items graded in each, and inclusion of levels from binary (presence/absence) to 4-level ordinal scoring. Recommendations specific to the imaging of each joint, consisting of anatomical planes and MRI sequences were constructed as a preliminary, minimally necessary imaging protocol to supplement the scoring system.
Conclusions: A novel WB-MRI scoring system for JIA was developed by consensus. Further iterative refinements, feasibility, reliability and responsiveness testing are warranted in upcoming studies.