The OMERACT MRI in Enthesitis Initiative: Definitions of Key Pathologies, Suggested MRI Sequences and Novel Heel Enthesitis Scoring System (HEMRIS)

Objective: To develop and validate an enthesitis MRI-scoring system for spondyloarthritis/psoriatic arthritis, using the heel as model.

Methods: Consensus definitions of key pathologies and three heel enthesitis multi-reader scoring exercises were done, separated by discussion, training and calibration.

Results: Definitions for bone and soft tissue pathologies were agreed. In final exercise, median pairwise single-measures intra-class correlation coefficients(ICCs; patient-level) for entheseal inflammation status/change scores were 0.83/0.82 for all readers. For radiologists and selected rheumatologists ICCs were 0.91/0.84 and quadratic-weighted kappas(lesionlevel) 0.57-0.91/0.45-0.81.

Conclusion: The proposed definitions and heel enthesitis scoring system (HEMRIS) are reliable among trained readers and promising for clinical trials.