Qualitative and Quantitative Inter-Observer Agreement of Multiparametric Whole-Body MRI in Staging and Follow-Up of Myeloma Patients

<b>Background</b>: Whole-body magnetic resonance imaging (WB-MRI) is incorporated into international guidelines and recommendations for imaging patients with multiple myeloma. The aim of this study was to investigate inter-observer agreement of radiologists with different levels of expertise in reporting whole-body MRI performed along MY-RADS criteria in myeloma at baseline and in evaluating response to therapy to better certify the use of these criteria. <b>Methods</b>: A total of 52 patients with symptomatic myeloma at first presentation (47) or relapse (5) and planned for a new line of therapy were included. All patients completed baseline whole-body MRI within 1 month prior to starting treatment. A total of 25 patients were evaluated with WB-MRI within 1 month after therapy. Each scan was reported independently by three radiologists using MY-RADS. Differences in observer scores were compared using analysis of variance (ANOVA), and inter-observer agreement was assessed using the intra-class correlation coefficient (ICC). <b>Results</b>: Interobserver agreement was excellent for all anatomic regions (> 0.81), both at baseline and at follow-up. Quantitative MRI analysis demonstrated that there was no significant difference in mean observer scores for the whole skeleton, and ICC demonstrated excellent inter-observer agreement at 0.9197 for ROI dimension, 0.94 for ADC values, and 0.98 for rFF%. <b>Conclusion</b>: MY RADS has excellent inter-observer agreement in reporting symptomatic myeloma at baseline and follow-up after therapy. In our study, there was no discrepancy between skeletal regions, highlighting specific areas of difficulty.