Role of Molecular Imaging with PET/MR Imaging in the Diagnosis and Management of Brain Tumors

Imaging protocols and classifications of CNS tumors have been changing at a torrid pace. Brain PET imaging increasingly is used to supplement MR imaging in the clinical management of glioma. The recently proposed RANO guidelines recommend PET imaging as the standard of care in evaluation of primary brain tumors.F-18-FDG-PET has been the workhorse of nuclear medicine and has been employed in brain tumor imaging for nearly50 years, representing the true intertumoral meta-bolism. Although AA tracers have been developed directly with tumor imaging in mind, many were originally employed for malignancies of other organ systems, with variable success.99Despitethe many proposed advantages of various non-F-18-FDG tracers, there still exist limitations(Table 5). Additionally, their uptake may reflect BBB dysregulation but not necessarily other clinically significant pathophysiological parameters beyond what can be ascertained from MR imag-ing. Although studies in these novel tracers pro-vide valuable initial guidance, further validation from large, prospective trials is required. Hybrid PET/MR imaging is a unique imaging modality that has the potential to improve both the diagnostic accuracy and the follow-up of patients with brain tumors.