PET method detects dementia, including Alzheimer's

Ah, we are but mere mortals, and scientific research has a way of reminding us precisely how.

Not only has one recent study found that humans can experience age-related neurological decline as early as 45, but scientists are also reporting in the Journal of Nuclear Medicine that positron emission tomography (PET) can safely and accurately detect dementia early on.

The technique, according to lead author Nicolaas Bohnen in a news release, not only helps diagnose dementia, but also improves physician confidence: "This process can be difficult for physicians, especially when evaluating younger patients or those who have subtle signs of disease."

Dementia is a big word. Rather than indicating a specific illness or problem, it is defined as a pattern of symptoms indicative of loss of cognition, whether caused by disease or injury.

By using PET, which provides 3D images of biological processes in our bodies, and injecting the radioactive marker (18)F-FDG to find specific regions of metabolic decline in the brain, researchers are able to see even the faintest signs of dementia play out far earlier than they might detect outward signs such as changes in personality.

Researchers say the method, which they're calling FDG-PET, not only identifies dementia, but also specific forms of dementia previously diagnosed only when other forms were ruled out.

"This is a major shift in disease definition, as previously an Alzheimer's diagnosis was based mainly on a process of evaluating patients to exclude possible trauma, hemorrhage, tumor or metabolic disorder," says Bohnen, a professor of radiology and neurology at the University of Michigan in Ann Arbor. "Now it is becoming a process of inclusion based on biomarker evidence from molecular imaging."

This test is one of many under investigation for imaging diseases such as Alzheimer's. The marker comprises a radionuclide (an atom that regularly emits radioactive particles) and fluorodeoxyglucose (hence the acronym FDG), which mimics glucose. By watching cells metabolize FDG, physicians can pinpoint abnormalities--such as reductions in the metabolism of different lobes of the cerebral cortex--to confirm a disorder.

If this new method has you worried that your doctors may now be able to pinpoint the precise nature of your neurological decline, consider this: the earlier the diagnosis, the more likely you are to exercise some control over it.