Association of synaptic density and glucose metabolism with cognitive performance in early Alzheimer's disease: a PET imaging study with [11C]UCB‐J and [18F]FDG

Traditionally, [18F]FDG PET has been used in Alzheimer’s disease (AD) as a surrogate marker of disease progression and is highly correlated with cognitive and functional decline. Synaptic loss is an early pathological event and a major structural correlate with cognitive impairment, although this is based on limited post‐mortem studies at more severe disease stages. Recently, we have confirmed these neuropathologic studies in vivo, using [11C]UBC‐J PET to demonstrate significant correlations between synaptic density and cognitive performance in early AD. In this study, we examined the relationship between synaptic density, glucose metabolism, and cognitive performance in early AD using [11C]UCB‐J PET, [18F]FDG PET, and an extensive neuropsychological battery.