Systematic calibration reduces sources of variability for the preliminary OMERACT juvenile idiopathic arthritis MRI- sacroiliac joint score (OMERACT JAMRIS-SIJ)

Objective: To determine whether systematic calibration enhances scoring proficiency of the OMERACT juvenile idiopathic arthritis MRI-Sacroiliac Joint score (JAMRIS-SIJ) and whether contrast-enhancement enhances its performance. Methods: MRI SIJ scans of 50 cases with juvenile spondyloarthritis were scored by 7 raters after calibration with 3 different knowledge transfer tools. Results: Calibrated readers achieved greater reliability for scoring certain inflammatory and structural lesions. Sensitivity and reliability for scoring inflammatory lesions was greater on fluid-sensitive compared to contrast enhanced sequences. Conclusion: Systematic calibration should be implemented prior to the use of JAMRIS-SIJ for clinical trials. It is unlikely that contrast-enhanced MRI will improve the performance of this method.

Automated summary

This study aimed to investigate whether systematic calibration improves the scoring proficiency of JAMRIS-SIJ and whether contrast-enhancement enhances its performance. The results showed that calibrated readers achieved greater reliability in scoring specific inflammatory and structural lesions. Sensitivity and reliability for scoring inflammatory lesions were higher on fluid-sensitive sequences compared to contrast-enhanced sequences. Therefore, systematic calibration should be implemented before using JAMRIS-SIJ in clinical trials, and it is unlikely that contrast-enhanced MRI will improve the performance of this method.