Hybrid Simultaneous Whole-Body 2-[18F]FDG-PET/MRI Imaging in Newly Diagnosed Multiple Myeloma: First Diagnostic Performance and Clinical Added Value Results

Objectives Mixing diagnostic and prognostic data provided by whole-body MRI (WB-MRI) and 2- 18 F-fluorodeoxyglucose (2-[ 18 F]FDG) positron emission tomography (2-[ 18 F]FDG-PET) from a single simultaneous imaging technique for newly diagnosed multiple myeloma (NDMM) initial workup seems attractive. However, to date, the published data are scarce and this possibility has not been fully explored. In this prospective study, we aimed to explore the diagnostic performance and added clinical value of WB-2-[ 18 F]FDG-PET/MRI imaging in NDMM. Methods All patients with confirmed NDMM at the Nantes University Hospital were prospectively enrolled in this study and underwent WB-2-[ 18 F]FDG-PET/MRI imaging on a 3-T Biograph mMR before receiving treatment. Before imaging, they were considered either as symptomatic or as smoldering MM (SMM). Diagnostic performance of global WB-2-[ 18 F]FDG-PET/MRI imaging, as well as PET and MRI separately for FL and diffuse BMI detection, was assessed and compared in each group. PET-based (maximal standardized uptake value, SUV max ) and MRI-based (mean apparent diffusion coefficient value, ADC mean ) quantitative features were collected for FL/para-medullary disease (PMD)/bone marrow and were compared. Results A total of 52 patients were included in this study. PET and MRI were equally effective at detecting patients with FL (69% vs. 75%) and with diffuse BMI (62% for both) in the symptomatic MM group. WB-2-[ 18 F]FDG-PET/MRI imaging detected FL in 22% of patients with SMM (with a higher diagnostic performance for MRI), resulting in a significant impact on clinical management in this population. SUV max and ADC mean quantitative features were weakly or not correlated. Conclusions WB-2-[ 18 F]FDG-PET/MRI could represent the next-generation imaging modality for MM. Key Points • Whole-body 2-[ 18 F]FDG-PET/MRI imaging detected at least one focal bone lesion in 75% of patients with symptomatic multiple myeloma, and PET and MRI were equally effective at identifying patients with a focal bone lesion. • Whole-body 2-[ 18 F]FDG-PET/MRI imaging detected a focal bone lesion in 22% of patients with smoldering multiple myeloma (with a higher diagnostic performance for MRI). • MRI had a significant impact on clinical management of smoldering multiple myeloma.