Spectrum of [18F]FDG PET/CT Findings in Primary Central Nervous System Lymphoma - A Pictorial Essay

Primary central nervous system lymphoma (PCNSL) is a rare, aggressive variant of extranodal non-Hodgkin's lymphoma. Although gadolinium-enhanced magnetic resonance imaging remains the initial imaging modality of choice, a whole-body F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is imperative to exclude systemic lymphomatous involvement. Furthermore, the metabolic parameter, maximum standardized uptake value (SUV_max) of the lesion, tumor-to-normal cerebral tissue SUV_max ratio, and FDG uptake patterns help in differentiating intracranial lymphomas from High-grade Glioblastoma Multiforme (HGM) and infectious lesions, and hence, consolidating the diagnosis. In this pictorial essay, we present a series of PCNSL cases, representing the different imaging characteristics and metabolic uptake patterns.