Computer Program Assesses Alzheimer's Risk

Scientists have devised a brain scan-based computer program that rapidly and effectively measures metabolic activity in a major area of the brain affected in the early stages of Alzheimer's disease (AD).

Utilizing the program, the researchers established that decreases in brain metabolism in healthy people were linked with the later development of the debilitating disorder, AD, according to a new study.

"This is the first demonstration that reduced metabolic activity in the hippocampus may be used to help predict future Alzheimer's disease,” said Lisa Mosconi, Ph.D., a research scientist in the department of psychiatry, New York University School of Medicine (NYU, NY, USA), who developed the computer program and was the principal investigator of the study.

The computer program consists of an image analysis method that allows researchers to standardize and computer automate the sampling of positron emission tomography (PET) brain scans. The NYU scientists hope the method will enable clinicians to measure the metabolic rate of the hippocampus and identify lower-than-normal metabolic activity.

HipMask uses magnetic resonance imaging (MRI) to anatomically probe the PET scan. MRI was utilized to determine the total volume of the hippocampus and then to define that portion (in particular the HipMask) that was shared by all subjects, regardless of their disease status. The HipMask was applied to PET scans to obtain estimates of the hippocampal glucose metabolism.

The researchers followed 53 healthy individuals between the ages of 54 and 80 for at least nine years, and in some cases for as long as 24 years. All subjects received two flurodeoxyglucose (FDG)-PET scans--one at baseline and a follow-up after three years. Thirty individuals had a second follow-up scan after an additional seven years. In total, there were 136 PET scans.

The investigators utilized the HipMask for all 136 scans. The findings demonstrated that hippocampal glucose metabolism, as determined by the HipMask, was considerably reduced from 15% to 40% on the first scan, compared to controls, of those 25 subjects who would later experience cognitive decline related to either mild cognitive impairment or to AD. The investigators discovered that the baseline hippocampal glucose metabolism was the only brain or clinical assessment that forecasted future cognitive decline.




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