P15.04.B Serial18F-fluciclovine PET-CT and multiparametric MRI during chemoradiation for glioblastoma - an exploratory clinical study with pre-clinical correlation

Abstract Background Positron emission tomography (PET) using anti-1-amino-3-18fluorine-fluorocyclobutane-1-carboxylic acid (18F-fluciclovine) shows preferential glioma cell uptake with low activity in normal brain. Dynamic contrast-enhanced (DCE) MRI may also be used to investigate regions of that do not show gadolinium-enhancement on post-contrast T1-weighted MR sequences (Gd-T1) and reflect tumour infiltration beyond the Gd-T1 enhancing margin. There is a paucity data how 18F-fluciclovine correlates DCE-MRI activity, it biology whether significant changes occur during treatment. The aims this pilot study were: 1 To compare PET, patients undergoing chemoradiotherapy for glioblastoma (GBM) 2 correlation between uptake, findings, pre-clinical model. Material Methods 18F-fluciclovine-PET-CT including were acquired before, after adjuvant (60 Gy 30 fractions temozolomide) GBM patients. volumes manually contoured, PET defined semi-automatic thresholding. was subtracted from identify areas volume boundary similarity outside measured Dice coefficient (DSC). CT-2A cells stereotactically injected into right striatum 8 10-week-old C57BL6J mice they underwent PET-CT. Post-mortem brains immunohistochemistry staining ASCT2 (amino transporter), nestin (stemness) Ki-67 (proliferation) assess biologically active tumour. Results 6 recruited (GBM 1-6). For 1-3: greater than DCE-MRI, turn Gd-T1. 4-6, similar both volumes. 1-3 had lower overall survival 4-6: median 249 vs. 903 days. Gd (on DCE-MRI) seen margins standard volume. Comparing these margins, DSC, suggesting distinct fluciclovine uptake. Pre-clinical PET-CT demonstrated tumour-specific which corresponded based immunostaining Ki-67, ASCT2. Conclusion joint clinical suggest 18F-fluciclovine-PET depicted by MRI-DCE are associated poorer prognosis GBM. model confirmed reflected