Glucose-corrected standardized uptake value in the differentiation of high-grade glioma versus post-treatment changes.

Abstract

BackgroundStandardized uptake values (SUVs) of fluorine-18 fluorodeoxyglucose PET (18F-FDG PET) are used widely to differentiate residual or recurrent high-grade gliomas from post-treatment changes in patients with brain tumors. The aim of this study is to assess the accuracy of SUV corrected by blood glucose level (SUVgluc) compared with various quantitative methods in this role.Materials and methodsIn 55 patients with dynamic 18F-FDG PET scans, there were 97 glioma lesions: glioblastoma (n=60), grade III gliomas (n=22), grade III or IV gliomas (n=6), grade I/II (n=7), and prebiopsy lesions (n=2). The final actual diagnosis was made on the basis of pathology (n=33) and clinical outcome (n=64). Dynamic 18F-FDG PET scans were processed to generate parametric images of SUVgluc, SUVmax, and glucose metabolic rate (GMR). Lesion to cerebellum ratios (SUVRc) and contralateral white matter ratios (SUVRw) were also measured. The SUVgluc was calculated as SUVmax×blood glucose level/100.ResultsUsing the thresholds of SUVmax>4.6, SUVRc>0.9, SUVRw>1.8, SUVgluc>4.3, and GMR>12.2 μmol/min/100 g to represent positivity for viable tumors, the accuracies were the same for the SUVgluc and SUVRw (80%) and were higher than the conventional SUVmax (72%). The area under the receiver operating characteristic curve for the SUVgluc (0.8933) was better than that for the SUVmax (0.8266) (P<0.01) and was similar to those of the GMR (0.8622), SUVRc (0.8606), and SUVRw (0.8981).ConclusionThese results suggest that SUVgluc may aid in the differentiation of residual or recurrent high-grade tumor from post-treatment changes in patients with abnormal blood glucose levels. The simplicity of the SUVgluc avoids the complexity of kinetic analysis or the requirement of a reference tissue.