Effects of hyperglycemia on fluorine-18-fluorodeoxyglucose biodistribution in a large oncology clinical practice

Aim Suggested cutoff points of blood glucose levels (BGL) before F-18-FDG PET/CT scanning vary between 120 and 200mg/dl in current guidelines. This study's purpose was to compare the frequency of abnormal fluorine-18-fluorodeoxyglucose (F-18-FDG) biodistribution on PET/CT scans of patients with various ranges of abnormal BGL and to determine the effect of BGL greater than 200mg/dl on F-18-FDG uptake in various organs.Patients and methods F-18-FDG PET/CT scans were retrospectively reviewed for 325 patients with BGL greater than 120mg/dl at the time of scan and 112 with BGL less than or equal to 120mg/dl. F-18-FDG biodistribution was categorized as normal, mildly abnormal, or abnormal by visual analysis of brain, background soft tissue, and muscle. Mean standardized uptake values (SUVmean) in brain, liver, fat (flank), gluteal muscle, and blood pool (aorta) were recorded. F-18-FDG biodistribution frequencies were assessed using a nonparametric chi(2)-test for trend. Normal organ SUVs were compared using Kruskal-Wallis tests using the following BGL groupings: <= 120, 121-150, 151-200, and <= 201 mg/dl.Results Although higher BGL were significantly associated with an increased proportion of abnormal biodistribution (P<0.001), most patients with BGL less than or equal to 200mg/dl had normal or mildly abnormal biodistribution. Average brain SUVmean significantly decreased with higher BGL groupings (P < 0.001). Average aorta, gluteal muscle, and liver SUVmean did not significantly differ among groups with BGL greater than 120mg/dl (P = 0.66, 0.84, and 0.39, respectively), but were significantly lower in those with BGL less than or equal to 120mg/dl (P <= 0.001). Flank fat SUVmean was not significantly different among BGL groups (P = 0.67).Conclusion Abnormal F-18-FDG biodistribution is associated with higher BGL at the time of scan, but the effects are negligible or mild in most patients with BGL less than 200mg/dl. Although mildly increased soft tissue uptake is seen with BGL greater than 120mg/dl, decline in brain metabolic activity correlated the most with various BGL. Copyright (C) 2018 Wolters Kluwer Health, Inc. All rights reserved