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Researchers test MRI technique to diagnose Alzheimer's

November 18, 2011
by root
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In the effort to develop an accessible method of diagnosing Alzheimer's disease, researchers are putting a new “spin” on existing technology—one that could change how the disease is currently tested for.

Researchers from the Perelman School of Medicine at the University of Pennsylvania have found a way to measure changes in brain function by utilizing a magnetic resonance imaging (MRI) technique called “Arterial spin labeling.” If proven successful, the Arterial spin labeling test could prove to be a safer and less expensive option than PET scans, which expose subjects to radioactive materials.

Two studies on the technique currently appear in Alzheimer's and Dementia: The Journal of the Alzheimer's Association and Neurology, the medical journal of the American Academy of Neurology.

Arterial spin labeling-MRI can be used to measure neurodegenerative changes in a similar way that fluorodeoxyglucose Positron emission tomography (FDG-PET) scans are currently being used to measure glucose metabolism in the brain, researchers said. Both tests correlate with cognitive decline in patients with Alzheimer's disease.

“In brain tissue, regional blood flow is tightly coupled to regional glucose consumption, which is the fuel the brain uses to function,” researchers said. “Increases or decreases in brain function are accompanied by changes in both blood flow and glucose metabolism. We designed [Arterial spin labeling] to allow cerebral blood flow to be imaged noninvasively and quantitatively using a routine MRI scanner.”

When Alzheimer's disease is suspected, patients typically receive an MRI initially to look for structural changes that could indicate other medical causes, such as a stroke or brain tumor. Researchers argued that Arterial spin labeling adds only an addition 10-20 extra minutes to the MRI test, “turning a routine clinical test (structural MRI) into both a structural and functional test.”

In the Alzheimer's and Dementia study, Arterial spin labeling and PET images from 13 patients diagnosed with Alzheimer's and additional age-matched controls were analyzed by visual inspection. Independent, blinded review of the two tests by expert nuclear medicine physicians demonstrated similar abilities to rule out and diagnose Alzheimer's. Neither tests showed a clear advantage from quantitative testing.

Additional studies will focus on larger sample sizes including patients with mild cognitive impairment and other kinds of neurodegenerative conditions.

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