Whole-body diffusion-weighted MRI and 18F-FDG PET/CT can discriminate between different lymphoma subtypes

•Indolent non-Hodgkin lymphoma (NHL) showed significantly lower mean apparent diffusion coefficient (ADC) values than the other two lymphoma groups.•The overall analysis (OS) showed a relationship between increased mean ADC and longer OS.•DWI could be a useful method for visualizing transformation from indolent to aggressive NHL.