Tracking Alzheimer's

06/20/04

UCLA scientists use FDDNP-PET to detect and quantify Alzheimer's disease in living patients

PHILADELPHIA, PA, June 21, 2004 –The current method of diagnosing Alzheimer's disease (AD) is clinical. By assessing symptomatic behavior such as memory loss, language impairment, delusions, and dementia, a physician can only give a "probable AD" diagnosis for a living patient. The gold standard of AD diagnosis is brain autopsy for detection of two types of brain lesions--neurofibrillary tangles and beta amyloid plaques.

A technique developed by researchers at UCLA makes it possible to detect and measure the levels of both types of lesions in the brains of living AD patients. Using the radiotracer 18F-FDDNP, a molecule that binds to the tangles and plaques, and positron emission tomography (PET), researchers can see how 18F-FDDNP accumulates in various areas of the brain. Combined with the results of PET studies using FDG, a glucose radiotracer that can demonstrate and measure decrease in brain metabolic activity caused by AD, it provides valuable information about disease status.

The results of a study to determine levels of 18F-FDDNP binding in different brain areas and to establish the pattern of 18F-FDDNP brain distribution in AD patients and healthy volunteers were presented at the Society of Nuclear Medicine's Annual Meeting in Philadelphia on June 21. Levels of 18F-FDDNP binding were consistently higher in several brain regions of AD patients compared to control subjects. The results accurately and effectively separated the AD patients from the control group. The pattern of 18F-FDDNP binding distribution correlated with the known patterns of distribution of tangles and plaques in the brains of AD patients as determined by postmortem examination.

According to UCLA's Vladimir Kepe, PhD, "Our findings with 18F-FDDNP PET facilitate progress toward a better understanding of the disease in living patients. We can trace the indicators of disease, determine which areas of the brain are already affected and, most importantly, determine to what extent these brain regions are affected."

The study, conducted by researchers at the Department of Molecular and Medical Pharmacology, The David Geffen School of Medicine at UCLA, included 13 patients with probable AD and 10 control patients. Each was given a PET scan with 18F-FDDNP to determine the patterns and the levels of 18F-FDDNP binding. All subjects also received FDG PET scans to determine which areas of the brain were becoming less active due to disease progression. By combining these two methods, the researchers developed an extremely accurate picture of the level of pathological changes in the brains of the AD patients.

Dr. Kepe concluded, "This opens opportunities for use of PET with 18F-FDDNP, not only for the possible diagnosis in early stages of the disease but also for testing the effects of future experimental drugs developed to prevent lesion formation and for monitoring the effects of the drugs aimed at removing the lesions."

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
    Published on PsychCentral.com. All rights reserved.

 

 

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