A simplified comparison of two distinct types of iron-related bone-marrow physiology related to [18F]FDG PET/MRI is presented in Fig. 6B. In the setting of anemia of inflammation, inflammatory cytokines and hepcidin suppress iron absorption and erythropoiesis, and increase non-heme iron storage on the marrow resulting in high R2* relaxation rates and decreased bone-marrow signals on DWI. Here, HAMP is linked to anemia (phenotype).