F-18-Fet And F-18-Choline Pet-Ct In Patients With Mri-Suspected Low-Grade Gliomas: A Pilot Study

Aim To investigate the diagnostic accuracy of O-(2-[F-18]fluoroethyl)-L-tyrosine (F-18-FET) and fluoromethyl-(F-18)dimethyl-2-hydroxyethyl-ammonium chloride (F-18-FCH) computed tomography (CT) in patients with primary lowgrade gliomas (LGG).Methods The study enrolled patients with magnetic resonance imaging (MRI)-suspected LGG. Patients underwent both F-18-FET and F-18-FCH positron emission tomography (PET)- CT. Brain PET-CT was performed according to standard protocol - 20 minutes after intravenous injection of 185 MBq of F-18-FET and 185 MBq of F-18-FCH PET. Surgery and pathohistological diagnosis were performed in the next two weeks.Results We observed significantly better concordance between tumor histology and F-18-FET PET (weighted Kappa 0.74) compared with both F-18-FCH (weighted Kappa 0.15) and MRI (weighted Kappa 0.00). Tumor histology was significantly associated with F-18-FET (odds ratio 12.87; 95% confidence interval [CI], 0.49-333.70; P = 0.013, logistic regression analysis). Receiver operating characteristic curve analysis comparing F-18-FCH (area under the curve [AUC] 0.625, 95% CI 0.298-0.884) and F-18-FET (AUC 0.833, 95% CI 0.499-0.982) showed better diagnostic properties of F-18-FET (AUC difference 0.208, 95% CI -0.145 to 0.562, P = 0.248).Conclusion Performing PET-CT in patients with newly diagnosed LGG should be preceded by a selection of an appropriate radiopharmaceutical. F-18-FET seems to be more accurate than F-18-FCH in the LGG diagnosis.