[Amyloid PET in Alzheimer research].
Amyloid positron emission tomography (PET) has recently emerged as a non-invasive neuroimaging technique for visualizing the accumulation of fibrillar amyloid-beta in the living human brain. Among several proposed radioligand tracers, Pittsburgh compound-B (PiB) has gained worldwide acceptance as a standard amyloid PET probe in a very short period because of its strong impact. Several lines of evidences from PiB-PET studies have suggested that the accumulation of amyloid-beta starts during the preclinical stage of Alzheimer disease (AD) and reaches the plateau phase before or during the mild cognitive impairment (MCI) stage. Therefore, amyloid-beta may be useful as a biomarker of AD, not only for the very early diagnosis but also for monitoring the therapeutic effect of disease-modifying agents that may reduce the amount of deposited amyloid-beta in the brains of patients with AD. Positive findings on amyloid PET along with amnestic MCI has been shown to be a strong predictor of AD conversion. The amyloid imaging technique is also useful to differentiate non-AD type degenerative disorders such as argyrophilic grain dementia and neurofibrillary tangle-dominant dementia, which are cumulatively called as tauopathies. Recently, many amyloid PET-positive and cognitively normal subjects were found in PiB-PET studies. PiB-PET studies on healthy subjects have also shown that apolipoprotein (APO) E4 boosts the accumulation of amyloid-beta and may consequently accelerate the pathogenesis of AD. In order to evaluate the clinical significance of positive and negative findings on amyloid PET, further prospective studies and comparison studies on PET pathology are essential.
Ishii
Kenji
K
Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo, Japan.
D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds; D015415:Biomarkers / Q000378:metabolism; D002250:Carbon Radioisotopes; D006801:Humans; D010618:Phenanthrolines; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012249:Rhombencephalon / Q000000981:diagnostic imaging* / Q000378:metabolism*; D013844:Thiazoles
C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D015415:Biomarkers; D002250:Carbon Radioisotopes; D010618:Phenanthrolines; D019275:Radiopharmaceuticals; D013844:Thiazoles