Effects of varying serum glucose levels on 18F-FDG biodistri… : Nuclear Medicine Communications

Objective 

Hyperglycemia has been shown to influence fluorine-18 fluorodeoxyglucose (18F-FDG) uptake in tumor cells. Therefore, patients are instructed to fast for 6 h, while maintaining serum glucose levels at an acceptable range. The study was performed to evaluate the effect of fasting blood glucose levels on the biodistribution of 18F-FDG in various tissues including the liver, heart, bone marrow, skeletal muscle, and tumors.

Materials and methods 

Fingerstick fasting blood glucose is routinely measured on the morning of the procedure. The maximum standardized uptake value (SUVmax) in the right and left hepatic lobes, left ventricle, sacrum, thigh, and tumor was measured in 229 consecutive patients undergoing 18F-FDG PET/computed tomography for tumor. Patients were divided into three groups depending on their serum glucose levels: low (<100; n=53), medium (100–160; n=149), and high (160–201; n=27). A retrospective analysis of the relationship between glucose levels and standardized uptake value was performed.

Results 

There was a statistically significant increase in the average SUVmax in the right and left hepatic lobes as glucose levels increased (right lobe P=0.00144; left lobe P=0.03889). Subsequently, pairwise analysis was performed, revealing a statistically significant increase in SUVmax in the right hepatic lobe between low-glucose and medium-glucose groups and in both hepatic lobes between low and high groups (P<0.017). No significant difference was observed in any of the other measured tissues.

Conclusion 

This study shows a directly proportional relationship between blood glucose levels and nonpathologic 18F-FDG biodistribution in the right and left hepatic lobes. The influence of blood glucose on expected biodistribution patterns, particularly in the liver, should be considered during interpretation.