F-FET and [sup.18]F-choline PET-CT in patients with MRI-suspected low-grade gliomas: a pilot study.(RESEARCH ARTICLE)(fluorodeoxyglucose positron emission tomography/computed tomography, magnetic resonance imaging )

Aim To investigate the diagnostic accuracy of O-(2-[[sup.18]F]fluoroethyl)-L-tyrosine ([sup.18]F-FET) and fluoromethyl-([sup.18]F)dimethyl-2-hydroxyethyl-ammonium chloride ([sup.18]F-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 [sup.18]F-FET and [sup.18]F-FCH positron emission tomography (PET)-CT. Brain PET-CT was performed according to standard protocol--20 minutes after intravenous injection of 185 MBq of [sup.18]F-FET and 185 MBq of [sup.18]F-FCH PET. Surgery and pathohistological diagnosis were performed in the next two weeks. Results We observed significantly better concordance between tumor histology and [sup.18]F-FET PET (weighted Kappa 0.74) compared with both [sup.18]F-FCH (weighted Kappa 0.15) and MRI (weighted Kappa 0.00). Tumor histology was significantly associated with [sup.18]F-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 [sup.18]F-FCH (area under the curve [AUC] 0.625, 95% CI 0.298-0.884) and [sup.18]F-FET (AUC 0.833, 95% CI 0.499-0.982) showed better diagnostic properties of [sup.18]F-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. [sup.18]F-FET seems to be more accurate than [sup.18]F-FCH in the LGG diagnosis.