Segmented Total Disease Volume and Associated Apparent Diffusion Coefficient on Whole Body Diffusion-Weighted MRI Show Good Interobserver Agreement

Matthew D. Blackledge¹, Nina Tunariu¹, David J. Collins¹, Martin O. Leach¹, Dow-Mu Koh¹

Whole body DWI (WBDWI) allows the duo quantification of the total diseased diffusion volume and associated global mean/ median apparent diffusion coefficient (ADC), which are promising response biomarkers. However, the interobserver agreement of this approach has not been previously established. We found excellent interobserver agreement for segmenting total diseased diffusion volume on WBDWI and very good interobserver agreement for global median ADC values. These quantitative indices are robust and could be investigated more widely in future clinical trials, especially for the assessment of metastatic bone disease.