New MRI Technique May Predict Progress of Dementias

A new technique for analyzing brain images offers the possibility of using magnetic resonance imaging (MRI) to predict the rate of progression and physical path of many degenerative brain diseases, report scientists at the San Francisco VA Medical Center and the University of California, San Francisco.

The technique, developed by SFVAMC scientists in collaboration with a team led by Bruce Miller, MD, clinical director of the UCSF Memory and Aging Center, also supports mounting evidence that dementias spread through the brain along specific neuronal pathways in the same manner as prion diseases.

The scientists employed new computer modeling techniques to realistically predict the physical progression of Alzheimer's disease and frontotemporal dementia (FTD) using images of 14 healthy brains. The models were based on whole-brain tractography, an MRI technique that maps the neural pathways, or "communication wires," that connect different areas of the brain. The spread of disease along those pathways, as predicted by the models, closely matched actual MRI images of brain degeneration in 18 Alzheimer's patients and 18 FTD patients.

Their study was published in the March 22 edition of Neuron.

"The results need to be replicated, but they suggest that, by using this approach, we can predict the location and course of future brain atrophy in Alzheimer's, FTD and other degenerative brain diseases, based on just one MRI taken at the outset of the disease," said senior author Michael Weiner, MD, director of the SFVAMC Center for Imaging of Neurodegenerative Diseases. "This would be extremely useful in planning treatment, and in helping patients and families know what to expect as dementia progresses."

The progression of Alzheimer's disease and other dementias

Each person experiences dementia in their own way, but it can be helpful to think of the way the condition progresses as a series of stages. This factsheet outlines the characteristics of early-, middle- and late-stage Alzheimer's disease and briefly looks at how other forms of dementia progress.

Alzheimer's disease

Alzheimer's disease is a progressive illness. This means that the structure and chemistry of the brain become increasingly damaged over time. The person's ability to remember, understand, communicate and reason will gradually decline. Looking at Alzheimer's disease as a series of three stages can be a useful way of understanding the changes that occur over time. But it is important to realise that this view of Alzheimer's can only provide a rough guide to the course of the disease. This is because:

- some symptoms may appear earlier or later than indicated here, or not at all
- the stages may overlap - the person may need help with one task, but may be able to manage another activity on their ownThe way that a person experiences Alzheimer's disease will depend on many factors, including their physical make-up, their emotional resilience, the medication they take and the support they can rely on.