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3D-Video MRI Shows Progression in Alzheimer's
Disease
Laurie Barclay, MD
Feb. 20, 2003 — A three-dimensional video magnetic resonance
imaging (MRI) system described in the Feb. 1 issue of the Journal
of Neuroscience has been used to map the progression of
Alzheimer's disease (AD). The investigators suggest that this
time-lapse video technique might be useful for early detection and
measurement of response to treatment.
"For the first time, you can see Alzheimer's disease progressing
in living patients," lead author Paul Thompson, MD, from the David
Geffen School of Medicine at the University of California at Los
Angeles, says in a news release. "We were stunned to see a spreading
wave of tissue loss. Initially confined to memory areas, this loss
moved across the brain like a wild fire, destroying more and more
tissue as the disease progressed."
Dr. Thompson's group analyzed sequential brain MRI scans every
three months for two years in 12 patients with AD, aged 68.4 ± 1.9
years, and in 14 healthy elderly volunteers, aged 71.4 ± 0.9 years.
The video technique uses minute changes in MRI with time to
document the sequential destruction of temporal and limbic cortices
followed by frontal and occipital brain regions, sparing
sensorimotor cortices. The left hemisphere was preferentially
involved. Deficits correlated with progressively declining cognitive
status (P < .0006) and reflected the sequence of
neurofibrillary tangle accumulation observed at autopsy. After two
years, virtually the entire brain was affected, except for visual
and other areas that are spared clinically.
Control patients lost only 0.9% ± 0.9% of gray matter annually,
but patients with AD lost an average of 5.3% ± 2.3% per year. Local
gray matter loss rates in AD were faster in the left hemisphere than
the right (P < .029). In brain regions controlling memory,
annual loss of gray matter approached 10%. Although frontal regions
were spared early in the disease, loss was greater than 15% in later
stages. While distinguishing different phases of AD, the maps also
differentiated AD from normal aging.
"This type of imaging will allow doctors and researchers to
pinpoint where and how fast the disease is spreading," Dr. Thompson
says. "We will urgently apply this method to reveal how drugs and
vaccines combat the wave of brain damage caused by AD."
J Neurosci. 2003;23(3):994-1005
Reviewed by Gary D. Vogin, MD
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Laurie
Barclay, MD is a staff writer with WebMD. Medscape
Medical News is edited by Deborah Flapan, a news coordinator
at Medscape. Send press releases and comments to news@webmd.net.
Medscape Medical News 2003. © 2003 Medscape
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