[Amyloid Positron Emission Tomography in the Therapeutic Strategies for Alzheimer's Disease].
Amyloid positron emission tomography (PET) has been developed as a non-invasive neuroimaging technique that enables us to visualize the accumulation of fibrillar amyloid-beta (Aβ) in the living human brain with histopathological confirmation. As the deposition of fibrillar Aβ is the earliest detectable biomarker of Alzheimer's disease (AD), amyloid PET is useful not only to increase the probability of a correct diagnostic in clinical practice and clinical studies, but also to enrich appropriate participants in the clinical trials of disease modifying drugs for early stage of AD. The amyloid positivity has been shown to be affected by age and APOE ε4 allele presence. In combination with the emerging technique of tau imaging, amyloid PET will reveal details of the early pathophysiological mechanism of AD, which will lead to the development of effective disease modifying therapies and prevention strategies. Amyloid negativity by amyloid PET is the most reliable marker to exclude the possibility of AD in the differential diagnosis of dementia diseases. Therefore, amyloid imaging is also essential for the clinical studies and clinical trials targeting non-AD dementia diseases such as frontotemporal lobar degeneration, argyrophilic grain disease and neurofibrillary tangle dominant disease. Establishing an in vivo imaging technique to visualize tau and alpha synuclein will accelerate further understanding of non-AD dementias.