Diagnosis of Brain Tumors Using Amino Acid Transport PET Imaging with 18F-fluciclovine: A Comparative Study with L-methyl-11C-methionine PET Imaging.

OBJECTIVES: 18F-fluciclovine (trans-1-amino-3-[18F] fluorocyclobutanecarboxylic acid, [FACBC]) is an artificial amino acid radiotracer used for positron emission tomography (PET) studies, which is metabolically stable in vivo and has a long half-life. It has already been shown that FACBC-PET is useful for glioma imaging. However, there have been no reports evaluating the efficiency of FACBC-PET in the diagnosis of brain tumors in comparison with other PET tracers in clinical studies. The purpose of this study was to investigate the efficacy of FACBC-PET imaging in glioma diagnosis, compared to L-methyl- 11 C-methionine (MET)-PET.

METHODS: Six consecutive patients (four male, two female), who were clinically suspected of having high- or low-grade glioma, received both FACBC-PET and MET-PET within a two-week interval. T1-weighted, contrast-enhanced, T1-weighted, and fluid-attenuated inversion recovery magnetic resonance imaging was performed to assist with subsequent tissue resection. Visual findings and semi-quantitative analyses of FACBC and MET uptake, using standardized uptake values (SUVs) and lesion-to-contralateral normal brain tissue (LN) ratios, were evaluated to compare PET images.

RESULTS: SUVs for FACBC were lower than those for MET in the non-lesion cerebral cortex, brain stem, and cerebellar hemisphere. There was a weak positive correlation between FACBC and MET uptake in glioma tissue, although L/N ratios for FACBC were higher than those for MET in all the cases.

CONCLUSION: FACBC-PET showed higher contrast than MET-PET by both visual and semi-quantitative analyses and may therefore provide better assessment for the detection of glioma. This study was registered as clinical trial (No. JapicCTI-132289).