Fig. 1

Scheme for selection of study subjects. Two hundred ninety MM patients who underwent FDG PET/CT for initial staging were retrospectively enrolled. We excluded 29 cases who were lost to follow-up without completion of treatment, 14 cases who received local treatment only, and 10 cases for whom R-ISS stage information was unavailable. We additionally excluded nine cases whose PET images did not include the arms and one case that showed low FDG uptake of all bone lesions. Therefore, 227 patients were included in the final analyses. R-ISS: Revised Multiple Myeloma International Staging System