Comparative evaluation of F-18 FDOPA, F-18 FDG, and F-18 FLT-PET/CT for metabolic imaging of low grade gliomas

INTRODUCTION:: We undertook this prospective study to compare amino acid metabolism, glucose metabolism, and proliferation in primary and recurrent low grade gliomas using positron emission tomography (PET)/computed tomography with F-18 FDOPA, F-18 FDG, and F-18 FLTMethods: Fifteen patients with newly diagnosed or previously treated low grade gliomas (WHO grade I or II) were subjected to F-18-FDOPA, F-18 FDG, and F-18 FLT PET/computed tomography studies on consecutive daysThis included 2 patients in remission as control subjectsUptake of all the 3 tracers were analyzed visually and quantified using standardized uptake values and tumor to normal (T/N) ratiosThe accuracy of all the 3 PET tracers in the detection of newly diagnosed and recurrent low grade gliomas was comparedResults: F-18 FDOPA was positive in all cases of primary and recurrent low grade gliomas and negative in the patients in remissionTumor was visualized on F-18 FDG in 7 of 13 cases, F-18-FLT was positive in 4 of 13 casesAverage tumor standardized uptake values max for F-18 FDOPA (5.75 ± 4.9) and F-18 FLT (1.8 ± 0.91) was lower than that of F-18 FDG (8.5 ± 4.4)T/N ratios for F-18-FDOPA (2.3 ± 0.51) and F-18 FLT (1.8 ± 0.91) were higher than F-18 FDG (1.03 ± 0.64) providing good image contrast for tumor detection in positive casesCONCLUSION:: F-18 FDOPA scan is superior to both F-18 FLT and F-18 FDG for visualization of primary and recurrent low grade gliomasF-18-FLT should not be considered for evaluation of recurrent low grade gliomas.