Early [18F]FET-PET in Gliomas after Surgical Resection: Comparison with MRI and Histopathology

BACKGROUND: The precise definition of the post-operative resection status in high-grade gliomas (HGG) is crucial for further management. We aimed to assess the feasibility of assessment of the resection status with early post-operative positron emission tomography (PET) using [18F]O-(2-[18F]-fluoroethyl)-L-tyrosine ([18F]FET). METHODS: 25 patients with the suspicion of primary HGG were enrolled. All patients underwent pre-operative [18F]FET-PET and magnetic resonance imaging (MRI). Intra-operatively, resection status was assessed using 5-aminolevulinic acid (5-ALA). Imaging was repeated within 72 h after neurosurgery. Post-operative [18F]FET-PET was compared with MRI, intra-operative assessment and clinical follow-up. RESULTS: [18F]FET-PET, MRI and intra-operative assessment consistently revealed complete resection in 12/25 (48%) patients and incomplete resection in 6/25 cases (24%). In 7 patients, PET revealed discordant findings. One patient was re-resected. 3/7 experienced tumor recurrence, 3/7 died shortly after brain surgery. CONCLUSION: Early assessment of the resection status in HGG with [18F]FET-PET seems to be feasible.