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New York Consortium for Alzheimer Research and Education
The New York Consortium for Alzheimer Research and Education (N.Y.C.A.R.E.) is the joint effort of
the Alzheimer’s Association New York City Chapter and the Education and Information Cores of the
Alzheimer’s Centers — Columbia University, College of Physicians and Surgeons; Mount Sinai Medical Center; and New York University School of Medicine funded by the National Institute on Aging.
Early Detection Through Brain Imaging
The early identification of individuals at risk for
Alzheimer’s disease (AD) is fundamental to
developing preventative therapies. Recent years
have brought a wealth of data indicating that it is possible
to use brain imaging techniques to predict who is likely
to experience cognitive decline and dementia.
A typical early feature of AD is that certain areas of
the brain, called the medial temporal lobes, where the
memory centers are located, shrink in volume, leading
to impaired memory. The parietal lobe, which helps us
orient our bodies in space and decipher where and what
things are is also affected by Alzheimer’s disease. When
Alzheimer’s begins destroying the parietal lobe, victims
become lost and disoriented, even in familiar settings.
They also begin mixing up objects, thinking that a
computer is a television or that a mixing bowl is a soup
pot. The frontal lobe, which also is affected, helps carry
out purposeful behaviors and complex reasoning. When
Alzheimer’s strikes the frontal lobe, the person loses the
ability to plan and initiate complicated activities like
balancing a checkbook.
 These changes can be seen with standard brain
imaging techniques like magnetic resonance imaging
(MRI)
(Figure 1).
In addition to showing the structure of the brain,
newer techniques are capable of monitoring changes in
brain function. Different types of MRI can help examine
how much blood is flowing through different areas of the brain (cerebral blood flow) or the concentrations of
different substances in brain tissue. Changes in cerebral
blood flow and chemical composition of the brain have
been found in Alzheimer’s disease. Some researchers
believe these changes can be detected before there are
significant symptoms.
Positron emission tomography (PET) produces a
three-dimensional image, and can show the metabolic
rate of glucose by brain cells. It is known that healthy
brain cells use more glucose than sick ones. PET scans
show that patients with Alzheimer’s disease have reduced
glucose uptake in the medial temporal lobes, parietotemporal,
and frontal regions.
 Similar, but less-severe reductions are also found in
people who already show some memory impairment,
but do not yet have AD. A scientist at one of the
NYCARE partners, NYU Langone Medical Center,
Center of Excellence on Brain Aging, has recently found
evidence that there is a relationship between reduced
glucose metabolism in AD-vulnerable brain regions and a
maternal family history of AD in some cognitively normal
individuals.
Although brain-tissue volume reductions, blood flow
changes and decrease in glucose uptake are quite sensitive,
they are not very specific to Alzheimer’s disease. They can
also be seen in other diseases such as. stroke, epilepsy, and
other types of dementia. They are not 100% predictive. This is an area that will require much additional study in
the future.
Amyloid beta is a protein which accumulates in the
brain during the progression of Alzheimer’s disease. It is
so common that it is one of the hallmarks of this disease.
An experimental PET scan study in which a compound
called PIB is injected into the blood is able to reveal how
much amyloid has been deposited, because PIB attaches
itself to the amyloid and is visible with a PET scan.
Multiple experimental compounds are being studied to
determine whether they, too, will attach to brain amyloid
deposits and can be detected by the PET scan. These
new techniques will be a promising and significant
supplement to magnetic resonance imaging and glucose
uptake studies, and will undoubtedly contribute greatly to
early detection of Alzheimer’s disease in the future.
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