New computer program uses brain scans to assess risk of Alzheimer’s
13 July 2005
New York, USA. New York University School of Medicine researchers have
developed a brain scan-based computer program that quickly and accurately
measures metabolic activity in a key region of the brain affected in the
early stages of Alzheimer’s disease. Applying the program, they demonstrated
that reductions in brain metabolism in healthy individuals were associated
with the later development of the memory robbing disease, according to a new
"This is the first demonstration that reduced metabolic activity in the
hippocampus may be used to help predict future Alzheimer’s disease," says
Lisa Mosconi, PhD, a research scientist in the Department of Psychiatry, who
developed the computer program and led the new study. "Although our findings
need to be replicated in other studies," she says, "our technique offers the
possibility that we will be able to screen for Alzheimer’s in individuals
who aren’t cognitively impaired."
Dr. Mosconi and colleagues have recently published the technical details
of the program, called "HipMask," in the June 2005 issue of the journal
Neurology. She presented the findings on June 20 at the Alzheimer’s
Association International Conference on Prevention of Dementia held in
The computer program is an image analysis technique that allows
researchers to standardize and computer automate the sampling of PET brain
scans. The NYU researchers hope the technique will enable doctors to measure
the metabolic rate of the hippocampus and detect below-normal metabolic
The technique grew out of years of research by Mony de Leon, EdD,
professor of psychiatry and director of the Center for Brain Health. His
group was the first to demonstrate with CT and later with MRI scans that the
hippocampus, a sea-horse shaped area of the brain associated with memory and
learning, diminishes in size as Alzheimer’s disease progresses from mild
cognitive impairment to full-blown dementia.
Yet until now, there has been no reliable way to accurately and quickly
measure the hippocampal area of the brain on a PET scan. The hippocampus is
small, and its size and shape are affected greatly in individuals with
Alzheimer’s, making it difficult to sample this region. HipMask is a
sampling technique that uses MRI to anatomically probe the PET scan.
MRI relies on electromagnetic energy to excite water molecules in the
brain to create an anatomical map of the brain. The MRI was used in the
study to determine the total volume of the hippocampus and then to define
that portion (namely the HipMask) that was shared by all persons regardless
of their disease status. PET employs radioactively labeled glucose to show
the brain at work and the HipMask was applied to these scans to derive
estimates of the hippocampal glucose metabolism.
The researchers followed 53 healthy, normal subjects between the ages of
54 and 80 for at least 9 years and in some cases for as long as 24 years.
All subjects received two FDG-PET scans—one at baseline and a follow-up
after 3 years. Thirty individuals had a second follow-up scan after another
seven years. Altogether there were 136 PET scans.
The researchers applied the HipMask to all 136 scans. The results showed
that, compared to controls, hippocampal glucose metabolism, as determined by
the HipMask, was significantly reduced 15% to 40% on the first scan of those
25 individuals who would later experience cognitive decline related to
either mild cognitive impairment or to Alzheimer’s. The researchers found
that the baseline hippocampal glucose metabolism was the only brain or
clinical measure that predicted the future cognitive decline.
"Right now, we can show with great accuracy who will develop Alzheimer’s
nine years in advance of symptoms, and our projections suggest we might be
able to take that out as far as 15 years," says Dr. de Leon, whose
longitudinal study is funded by the National Institutes of Health (NIH).
"Our basic results will need to be replicated in other studies and
expanded to include PET data from diverse patient groups," adds Dr. De Leon.
"But we’re confident this is a strong beginning, demonstrating accurate
detection of early Alzheimer’s disease. Now we have a better tool to examine
disease progression, and we anticipate this might open some doors to
prevention treatment strategies."