The French researchers developed a technique that allows a computer to calculate the size of the hippocampus within minutes.

Colliot and colleagues tried their technique on 25 Alzheimer's patients, 24 patients with mild cases of cognitive impairment and memory loss, and 25 seniors who were healthy. They reported their findings in the July issue of Radiology.

The researchers found that the hippocampus was about a third smaller in the Alzheimer's patients than in the healthy ones and 19 percent smaller in those with cognitive impairment.

Doctors were able to correctly distinguish those with Alzheimer's' disease from healthy people 84 percent of the time.

Alzheimer's disease is not curable, but doctors can prescribe drugs to treat symptoms once they have a diagnosis, Colliot said.

At the moment, the new technique isn't ready for prime time, said Bryan. "A number of papers using different, but similar computer analytical approaches have been published, and there is no question that this will eventually be the preferred technique," he noted. "However, the different methods have not been sufficiently validated for routine use."

But once a technique is proven, it should help doctors diagnose Alzheimer's early and track whether medications are working properly, Bryan said.

More information

Learn more about diagnosing Alzheimer's disease from the U.S. National Institutes of Health.

SOURCES: Olivier Colliot, Ph.D., researcher, Cognitive Neuroscience and Brain Imaging Laboratory, Universite Pierre et Marie Curie, Paris; R. Nick Bryan, M.D., Ph.D., professor and chairman, Department of Radiology, University of Pennsylvania Health System, Philadelphia; July 2008, Radiol
'/>"/>