Affiliations: Memory and Aging Center, University of California San
Francisco, San Francisco, CA, USA | Department of Neurology, University of California San
Francisco, San Francisco, CA, USA | Helen Wills Neuroscience Institute, University of
California Berkeley, Berkeley, CA, USA | Lawrence Berkeley National Laboratory, Berkeley, CA,
USA
Note: [] Corresponding author: Gil D. Rabinovici, MD, UCSF Memory
& Aging Center, 350 Parnassus Ave., Suite 905, San Francisco, CA 94143,
USA. Tel.: +1 415 514 2374; Fax: +1 415 476 4800; E-mail:
grabinovici@memory.ucsf.edu
Abstract: Amyloid imaging represents a major advance in neuroscience, enabling
the detection and quantification of pathologic protein aggregations in the
brain. In this review we survey current amyloid imaging techniques, focusing on
positron emission tomography (PET) with ^{11}carbon-labelled
Pittsburgh Compound-B (^{11}C-PIB), the most extensively
studied and best validated tracer. PIB binds specifically to fibrillar
beta-amyloid (Aβ) deposits, and is a sensitive marker
for Aβ pathology in cognitively normal older
individuals and patients with mild cognitive impairment (MCI) and Alzheimer's
disease (AD). PIB-PET provides us with a powerful tool to examine in vivo
the relationship between amyloid deposition, clinical symptoms, and structural
and functional brain changes in the continuum between normal aging and AD.
Amyloid imaging studies support a model in which amyloid deposition is an early
event on the path to dementia, beginning insidiously in cognitively normal
individuals, and accompanied by subtle cognitive decline and functional and
structural brain changes suggestive of incipient AD. As patients progress to
dementia, clinical decline and neurodegeneration accelerate and proceed
independently of amyloid accumulation. In the future, amyloid imaging is likely
to supplement clinical evaluation in selecting patients for anti-amyloid
therapies, while MRI and FDG-PET may be more appropriate markers of clinical
progression.
