Evaluation of Early Dementia (Mild Cognitive Impairment).

Early diagnosis of Alzheimer disease (AD) is one of the major challenges for the prevention of this dementia. The pathologic lesions associated with AD develop many years before the clinical manifestations of the disease become evident, during a likely transitional period between normal aging and the appearance of first cognitive symptoms. AD biomarkers are needed not only to reveal these early pathologic changes but also to monitor progression in cognitive and behavioral decline and brain lesions. PET neuroimaging can reliably assess indirect and direct aspects of the molecular biology and neuropathology of AD. This article reviews the use of [18F] 2-fluoro-2-deoxy-D-glucose-PET and amyloid PET imaging in the early detection of AD.