Impacts of biological and procedural factors on semiquantification uptake value of liver in fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography imaging

Background: Increased metabolic activity of fluorodeoxyglucose (FDG) in tissue is not only resulting of pathological uptake, but due to physiological uptake as well. This study aimed to determine the impacts of biological and procedural factors on FDG uptake of liver in whole body positron emission tomography/computed tomography (PET/CT) imaging. Methods: Whole body fluorine-18 ( 18 F) FDG PET/CT scans of 51 oncology patients have been reviewed. Maximum standardized uptake value (SUV max ) of lesion-free liver was quantified in each patient. Pearson correlation was performed to determine the association between the factors of age, body mass index (BMI), blood glucose level, FDG dose and incubation period and liver SUV max . Multivariate regression analysis was established to determine the significant factors that best predicted the liver SUV max . Then the subjects were dichotomised into four BMI groups. Analysis of variance (ANOVA) was established for mean difference of SUV max of liver between those BMI groups. Results: BMI and incubation period were significantly associated with liver SUV max . These factors were accounted for 29.6% of the liver SUV max variance. Statistically significant differences were observed in the mean SUV max of liver among those BMI groups (P Conclusions: BMI and incubation period are significant factors affecting physiological FDG uptake of liver. It would be recommended to employ different cut-off value for physiological liver SUV max as a reference standard for different BMI of patients in PET/CT interpretation and use a standard protocol for incubation period of patient to reduce variation in physiological FDG uptake of liver in PET/CT study.