Analyzing structural brain changes in Alzheimer's disease

November 16, 2009
Serial MRI brain scans, taken six months apart, show progression from mild cognitive impairment to Alzheimer's disease, with significant atrophy (blue) and ventricle enlargement (orange/red). Credit: University of California, San Diego, UCSD

In a study that promises to improve diagnosis and monitoring of Alzheimer's disease, scientists at the University of California, San Diego have developed a fast and accurate method for quantifying subtle, sub-regional brain volume loss using magnetic resonance imaging (MRI). The study will be published the week of November 16 in the Proceedings of the National Academy of Sciences (PNAS).

By applying the techniques to the newly completed dataset of the multi-institution Alzheimer's Disease Neuroimaging Initiative (ADNI), the scientists demonstrated that such sub-regional volume measurements outperform available measures for tracking severity of Alzheimer's disease, including widely used cognitive testing and measures of global brain-volume loss.

The general pattern of resulting from Alzheimer's disease has long been known through autopsy studies, but exploiting this knowledge toward accurate diagnosis and monitoring of the disease has only recently been made possible by improvements in computational algorithms that automate identification of brain structures with MRI. The new methods described in the study provide rapid identification of brain sub-regions combined with measures of change in these regions across time. The methods require at least two brain scans to be performed on the same over a period of several months. The new research shows that changes in the brain's memory regions, in particular a region of the temporal lobe called the entorhinal cortex, offer sensitive measures of the early stages of the disease.

"Loss of volume in the hippocampus is a consistent finding when using MRI, and is a reliable predictor of ," said Anders M. Dale, PhD, professor of neurosciences and radiology at the UC San Diego School of Medicine, who led the study. "However, we have now developed and validated imaging biomarkers to not only track brain atrophy, but distinguish the early stages of Alzheimer's disease from changes related to normal aging."

The researchers at dozens of sites across the U.S. studied nearly 300 patients with mild cognitive impairment, 169 healthy controls and 129 subjects with AD and then measured rates of sub-regional cerebral volume change for each group. Power calculations were performed to identify regions that would provide the most sensitive outcome measures in clinical trials of disease-modifying agents.

"The technique is extremely powerful, because it allows a researcher to examine exactly how much brain-volume loss has occurred in each region of the brain, including cortical regions, where we know the bad proteins of Alzheimer's disease build up," said study co-author James Brewer, MD, PhD, a neurologist and assistant professor in the Departments of Radiology and Neurosciences at UC San Diego. "We are particularly excited to use the techniques in new clinical trials, but also to reexamine old clinical trial data where global measures of brain shrinkage were applied. These new findings suggest that such global measures are less sensitive than regional measures for detecting the changes specific to Alzheimer's disease - the changes these drugs are targeting."

Source: University of California - San Diego (news : web)

Related Stories

Recommended for you

New cellular approach found to control progression of chronic kidney disease

December 15, 2017
Researchers have demonstrated for the first time that extracellular vesicles - tiny protein-filled structures - isolated from amniotic fluid stem cells (AFSCs) can be used to effectively slow the progression of kidney damage ...

Testing shows differences in efficacy of Zika vaccines after one year

December 15, 2017
(Medical Xpress)—A large team of researchers with members from Harvard Medical School, Walter Reed Army Institute of Research, Bioqual Inc. and MIT has found that the efficacy of the three types of Zika vaccines currently ...

How to regulate fecal microbiota transplants

December 15, 2017
(Medical Xpress)—A small team of researchers at the University of Maryland, some with affiliations to the Veterans Affairs Maryland Health Care System, has written and published a Policy Forum piece in the journal Science ...

Screening could catch a quarter of hip fractures before they happen

December 15, 2017
Community screening for osteoporosis could prevent more than a quarter of hip fractures in older women - according to new research led by the University of East Anglia (UEA).

Urine test developed to test for tuberculosis

December 14, 2017
(Medical Xpress)—An international team of researchers has developed a urine test that can be used to detect tuberculosis (TB) in human patients. In their paper published in Science Translational Medicine, the group describes ...

40 years after first Ebola outbreak, survivors show signs they can stave off new infection

December 14, 2017
Survivors of the first known Ebola outbreak, which occurred in the Democratic Republic of the Congo in 1976, may be key to development of vaccines and therapeutic drugs to treat future outbreaks, according to a new study ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.