New Type of MRI Scan Spots Alzheimer's

Technique May Help With Early Diagnosis of Alzheimer's Disease

By Jennifer Warner
WebMD Health News

Reviewed By Louise Chang, MD

June 24, 2008 — A new type of MRI scan may help doctors spot early signs of Alzheimer's disease in the brain, paving the way for earlier treatment of the disease.

Researchers in France have developed an automated system for measuring brain tissue loss using magnetic resonance imaging (MRI) technology to help doctors diagnose Alzheimer's disease and mild cognitive impairment. Many people with mild cognitive impairment may go on to develop dementia.

In Alzheimer's disease, the buildup of certain proteins in the brain leads to brain cell and brain tissue death; the hardest-hit part of the brain is the hippocampus, which affects memory.

The automated MRI system helps in diagnosing Alzheimer's disease by speeding up the process of visually measuring shrinkage in the hippocampus consistent with Alzheimer's disease.

Until now, measurement of brain tissue loss associated with Alzheimer's disease had to be performed manually using a lengthy process known as MRI segmentation.

"Visually evaluating the atrophy of the hippocampus is not only difficult and prone to subjectivity, it is time-consuming," says researcher Olivier Colliot, PhD, of the Cognitive Neuroscience and Brain Imaging Laboratory in Paris, in a news release. "As a result, it hasn't become part of clinical routine."

"The performance of automated segmentation is not only similar to that of the manual method, it is much faster," says Colliot. "It can be performed within a few minutes versus an hour."

Visualizing Alzheimer's Disease

In the study, published in Radiology, researchers evaluated the new automated system in measuring brain tissue volume in the hippocampus of 25 people with Alzheimer's disease, 24 with mild cognitive impairment, and 25 healthy older adults.

The measurements were then compared to similar groups of patients evaluated with the manual MRI segmentation method.

The results showed a significant reduction in volume of the hippocampus in both the Alzheimer's and mild cognitive impairment groups compared with healthy adults. The average shrinkage of the hippocampus was 32% among those with Alzheimer's disease and 19% among those with mild cognitive impairment.

"Combined with other clinical and neurospychological evaluations, automated segmentation of the hippocampus on MR images can contribute to a more accurate diagnosis of Alzheimer's disease," says Colliot.

SOURCES: Colliot, O. Radiology, July 2008; vol 248: pp 194-201. News release, Radiological Society of North America.

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