Diagnostic imaging and new guideline

Hiroyuki Shimada

Department of Geriatrics and Neurology, Osaka City University Graduate School of Medicine

In the NIA/AA diagnostic guidelines, a new stage of Alzheimer disease (AD):“preclinical AD” has been proposed. In this stage, the affected individuals show increased accumulation of Aβ in the brain, as seen in AD pathology, but have normal cognition. After Klunk reported amyloid imaging with PiB, it has been reported that there are approximately 20-40% amyloid-positive individuals among cognitively normal elderly adults. These amyloid-positive, cognitively normal individuals are thus considered as having preclinical AD. The Anti-Amyloid Treatment in Asymptomatic AD (A4) trial is the clinical trial designed to treat individuals at this stage, by administering anti-amyloid antibodies for decreasing the “upstream” accumulation of Aβ.

Address correspondence to Dr. Hiroyuki Shimada, Department of Geriatrics and Neurology, Osaka City University Graduate School of Medicine (1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan)