11 The Early Detection of Alzheimer's Disease with Positron Emission Tomography

Abstract

Abstract Reductions in the cerebral metabolic rate of glucose (CMRglc), a measure of neuronal function, have proven to be a promising tool in the early diagnosis of Alzheimer's disease (AD). FDG-PET imaging demonstrates progressive CMRglc reductions in AD patients, the extent and topography of which correlate with symptom severity. There is increasing evidence that hypometabolism appears during the preclinical stages of AD and can predict decline years before the onset of symptoms. This chapter provides an overview of FDG-PET results in individuals at risk for developing dementia, including presymptomatic individuals carrying mutations responsible for early-onset familial AD, patients with mild cognitive impairment (MCI), nondemented carriers of the Apolipoprotein E (ApoE) e4 allele, cognitively normal subjects with a family history of AD, subjects with subjective memory complaints, and the normal elderly followed longitudinally until they expressed the clinical symptoms of AD. Finally, this chapter discusses the potential to combine different PET tracers and cerebrospinal fluid (CSF) markers of pathology to improve the early detection of AD.