April 12, 2012

Mapping the Brain With Dementia

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Joseph V. Madia, MD By:

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Alzheimers and dementia progression might be predicted with MRI images and computer modeling

(dailyRx News) While finding effective treatments for Alzheimer's continues to challenge researchers, using MRI images to predict how the disease and other dementias spread may be closer at hand.

Such an image, interpreted with the computer technique described and tested in a new study, might provide families with better knowledge for planning when a person is diagnosed with Alzheimer's.

Further down the road, it may also be possible to use this information to contribute to finding ways to understand dementia and then explore more treatment possibilities.

"Talk to your doctor if you think you or a relative is starting to lose cognitive abilities."

Bruce Miller, MD, the clinical director of the University of California-San Francisco Memory and Aging Center, led the team that developed the technique, and Ashish Raj, PhD, now of Weill Medical College at Cornell University in New York, led the study.

Using 14 images of healthy brains, Miller and his colleagues used a new kind of computer modeling method to predict how Alzheimer's disease and a type of dementia called frontotemporal dementia might develop.

The method is a technique of MRI technology called "whole-brain tractography." It involves creating a kind of map of the neural pathways in the brain along which communication and information travels.

When Miller and his team compared the spread of disease in their computer model predictions to real-life MRI images from 18 Alzheimer's patients and 18 FT dementia patients, they found that the model images matched up with the ones of actual people.

Because this is a preliminary study, more studies will need to be conducted to confirm the validity of this MRI and computer modeling technique.

If further studies come up with similar results, then doctors may be able to use an initial MRI image at the start of a patient's symptoms to start predicting how disease will spread in the brains in the brains of people with Alzheimer's, dementia or similar degenerative brain diseases.

"This would be extremely useful in planning treatment, and in helping patients and families know what to expect as dementia progresses," said senior author Michael Weiner, MD, the director of the San Francisco VA Medical Center's Center for Imaging of Neurodegenerative Diseases.

The method would not necessarily work for everyone and has some limitations, especially if the MRI images cannot provide adequate or precise enough data. Also, a person whose brain is already significantly damaged may not benefit as much if the image quality is affected by the progression of the disease.

The published study did not provide information on potential costs of using this method, though the usual costs of MRI imaging would apply if and when this diagnostic testing becomes available to patients.

More studies are required before it can become clear how long it might take for this technique to be implemented for general patients.

Weiner said the results of this study provide additional evidence for a theory that researchers have recently been considering regarding how the disease spreads.

The theory is that Alzheimer's and similar dementia and brain disorders spread through "prions" in the brain. A prion is a diseased and deformed version of a protein in the brain.

Each prion destroys the part of the brain its in, and as they spread, the destruction of the brain worsens, causing the spread of the degenerative brain disease.

Another disease that spread through these destructive prions is mad cow disease. However, research into prions is still fairly new because scientists thought for many years - until the later part of the 20th century - that proteins could not cause infection on their own.

"The idea of a prion-like mode of progression in dementias, which many scientists are beginning to support, is that the misfolded protein in one neuron will infect a neighboring brain cell, causing proteins in that cell to misfold in turn, and that the spread of these misfolded proteins flows along certain networks in the brain," Weiner said.

There are different networks that certain diseases might spread along, but this area requires more research. Weiner said that this doesn't mean Alzheimer's or dementia is infectious in the contagious sense. Instead, all the passing along of infection occurs within a single person's brain.

The study was published March 22 in the journal Neuron. The research was funded by the National Institutes of Health and the University of California-San Francisco's California Alzeheimer's Disease Research Center. No conflicts of interest were noted.
 

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Reviewed by: 
Joseph V. Madia, MD
Review Date: 
April 12, 2012

Last Updated:
April 12, 2012