18F-Fluciclovine PET and Multiparametric MR Imaging

Methods: Patients with recurrent enhancing mass on MRI in the side of a diagnosed and treated high grade glioma or metastatic brain tumor and consenting to study protocol will undergo 18F-Fluciclovine PET/CT imaging once prior to surgery for brain tumor recurrence. Surgery for recurrent brain tumor will follow standard of care treatment that includes either biopsy of the region or interest or as complete as possible tumor resection followed by histopathological analysis. Outcome evaluation will be analysis of tumor histology and imaging results, comparison of MRI, MRSI, and 18F-Fluciclovine imaging and relationship of imaging findings with histopathology and anatomical location of recurrent tumor. Study Objectives 1. In this study, we will investigate the potential of 18F-fluciclovine to aid the visualization of residual or recurrent gliomas as depicted by 18F-Fluciclovine PET imaging compared to standard MRI sequences \[T1 weighted imaging (T1WI) with contrast, diffusion weighted imaging (DWI), perfusion weighted imaging (PWI), T2 weighted fluid attenuated inversion recovery (T2 FLAIR)\] using 3D image fusion. 2. To assess the residual or recurrent of glioma as depicted by 3D short echo time MR spectroscopic imaging (MRSI) using metabolic tumor markers such as elevated choline, myo-Inositol and lipids and reduced N-acetyl-aspartate (NAA) compared to standard MRI sequences (T1WI with contrast, PWI, T2 FLAIR) using 3D image fusion before neurosurgical intervention. 3. To spatially register the residual or recurrent glioma as depicted by 18F-Fluciclovine PET imaging with MR T1WI, DWI, PWI, and 3D MRSI to a) quantitate (SUVmax, SUVmean, ADCmean, rCBV, Cho, NAA, lipids, Cho/Cr, Cho/NAA) and correlate areas of PET+, T1WI+ and MRSI+ areas and b) characterize different metabolic profiles measured with MRSI in areas of glioma infiltration depicted by PET imaging and MRI. 4. Biopsy and pathology confirmation of tumor vs treatment-induced necrosis in spatially registered areas of interest will be performed. Safety analysis Although 18F-Axumin™ is an FDA approved PET imaging agent for biological recurrent prostate cancer with extensive safety and toxicity data already documented, all patients will be monitored closely for adverse reactions after administration.