To compare the diagnostic performance of 11C-acetate and 18F-FDG across hybrid PET/CT and PET/MRI platforms in patients with multiple myeloma (MM).

In this prospective pilot study, seven patients with MM underwent repeated-measures imaging with 18F-FDG PET/CT, 18F-FDG PET/MRI, 11C-acetate PET/CT, and 11C-acetate PET/MRI. In addition to lesion quantification, the lesions were visually scored for conspicuity. No functional sequences or contrast-enhancement was used in the MRI protocol.

11C-acetate detected a greater number of lesions and demonstrated higher visual conspicuity than 18F-FDG across both PET/CT and PET/MRI platforms.

11C-acetate PET imaging may offer improved lesion detection compared to 18F-FDG in MM. Although the advantage of PET/MRI was not observed over PET/CT in this context, further studies incorporating additional MRI sequences and larger cohorts are warranted.