FDG PET Imaging Evaluation of Neurodegenerative Dementias

Brain PET imaging with [F-18]fluorodeoxyglucose (FDG) has been used extensively for research and clinical applications in dementia. Since the invention of FDG in the 1970s and the initial applications to brain disorders, brain FDG PET has unveiled the pathophysiology of neurodegeneration, elucidated altered patterns of glucose metabolism in various dementing disorders, and advanced clinical applications for the evaluation of patients suffering from cognitive impairments. In this chapter, we will discuss: (1) indications of FDG PET in dementia evaluation; (2) image interpretation using statistical mapping technology; (3) pretest probability and referral bias; (4) differential diagnoses of Alzheimer’s disease (AD), frontotemporal dementia (FTD), and Dementia with Lewy bodies (DLB); (5) recognition of subtypes of AD and frontotemporal lobar degeneration (FTLD); (6) FDG PET findings of newly recognized neurodegeneration, Limbic-predominant age-related TDP-43 encephalopathy (LATE); and (7) increasing recognition of mixed dementia and co-pathologies and how FDG PET interpretation needs to evolve. FDG PET imaging remains a valuable tool for the evaluation of dementia owing to its relatively low cost, differential diagnostic performance, widespread availability, and physicians’ experience over more than four decades since the initial development.