The effect of volume of interest definition on quantification of lymph node immune response to a monkeypox virus infection assessed by 18F-FDG-PET

Background 2-deoxy-2-[18F]fluoro-D-glucose-positron emission tomography (18F-FDG-PET) is applied in the clinic for infection assessment and is under consideration for investigating the inflammatory/immune response in lymphoid tissue in animal models of viral infection. Assessing changes in 18F-FDG uptake of lymph nodes (LNs), primary lymphoid tissues targeted during viral infection, requires suitable methods for image analysis. Similar to tumor evaluation, reliable quantitation of the LN function via multiple 18F-FDG-PET sessions will depend how the volume of interest is defined. Volume of interest definition has a direct effect on statistical outcome. The current study objective is to compare for the first time agreement between conventional and modified VOI metrics to determine which method(s) provide(s) reproducible standardized uptake values (SUVs) for 18F-FDG uptake in the LN of rhesus macaques.