The Relation Between the Blood Glucose Level and the FDG Uptake of Tissues at Normal or Near-Normal PET/CT Imaging

Objective: The aim of this study was to evaluate the relation between the blood glucose level and 18F-FDG uptake in tissues at normal or near-normal PET/CT examinations. Material and Methods: Patients with newly diagnosed cancer who underwent 18F-FDG PET/ CT for initial staging were evaluated retrospectively. Sixty five patients (47 female, 18 male) with a normal or near normal FDG distribution were included this study. Mean standardized uptake value of the brain, heart, lung, mediastinum, pancreas, liver, spleen, skeletal muscle and bone marrow were calculated. Blood glucose levels measured immediately prior to administration of FDG were used. Results: There was a statistically significant positive correlation between the blood glucose level and liver and muscular FDG uptake. Brain FDG uptake value was negatively correlated with the glucose level. There was no correlation between the blood glucose level and other tissues' FDG uptake values. The patients with increased blood glucose levels showed significantly higher muscular and lower brain FDG uptake compared with patients with normal glucose levels. Conclusion: Effect of hyperglycemia during 18F FDG PET/CT imaging on normal tissues is variable. While skeletal muscle and brain are the most affected tissues, the liver is slightly affected in a clinically insignificant manner.