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

Abstract

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.

Association of Normal Organs Standardized Uptake Values with Serum Blood Glucose in F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography.

“…significant association with serum blood glucose and muscular uptake. Similar reports described the same finding (15,16) . Another published study by Zheng and colleagues investigated factors that may cause extensive skeletal muscle uptake, their results suggest that fasting time, gastric food residue and proportion of carbohydrate were independent risk factors (17) .…”

Unexpected focal fluorodeoxyglucose uptake in main organs; pass through or pass by?

“…Recognizing the significance of this relationship, guidelines outlined by the Society of Nuclear Medicine and Molecular Imaging and the European Association of Nuclear Medicine recommend conducting F-18 FDG PET/CT scans under stringent blood glucose control, specifically targeting concentrations lower than 11 mmol/L (approximately 200 mg/dL)[ 16 , 66 ]. Although a subset of recent literature suggests a limited impact of blood glucose levels on imaging outcomes[ 67 - 73 ], it is noteworthy that adherence to the established guidelines remains prevalent in the field.…”

Focal incidental colorectal fluorodeoxyglucose uptake: Should it be spotlighted?

“…Current guidelines from the European Association of Nuclear Medicine and the Society of Nuclear Medicine and Molecular Imaging recommend conducting F-18 FDG PET/CT when blood glucose is controlled, ideally below 11 mmol/L (approximately 200 mg/dL)[ 16 , 43 ]. While recent literature suggests limited impact of blood glucose levels on imaging outcomes[ 44 - 48 ], adherence to published guidelines remains widespread.…”