Monday, July 28, 2008

MRI captures images of brain lesions of Alzheimer's

Scientists reported they have captured images of brain lesions in rabbits similar to those found in people with Alzheimer's disease using conventional MRIs.

Amyloid plaques, which accumulate in the brain and are a hallmark of Alzheimer's, have been captured before through extra-high-power magnetic resonance imaging (MRI) scanners meant for use in animals and with PET scans.

But in this case, lead author John Ronald and his colleagues used regular-strength MRI scans. "We souped up a clinical-grade MRI for the ability to really detect very small ... structures," said Ronald, a doctoral candidate in the medical biophysics department at the University of Western Ontario Imaging Labs and Robarts Research Institute in London, Ontario, Canada.

The scans revealed "little signal voids within the MR image" caused by iron accumulation apparently resulting from the animals' high-cholesterol diet, Ronald explained. Subsequent autopsies showed that the voids corresponded with areas with amyloid plaque clusters.

The research was expected to be presented Sunday at the International Conference on Alzheimer's Disease in Chicago.

Although the scanners employed in the study are routinely used for humans, it's unclear what the results might actually mean for humans. But some hope is pinned on magnetic resonance imaging technology, which tends to be more available and less expensive than many other imaging systems.

Researchers have long been looking for ways to identify and diagnose the disease earlier in its progression.

"There is no way to diagnose a patient until after they die, so patients and families are left with the uncertainty of whether they have Alzheimer's or some other form of dementia," Ronald explained.

A radiologist prepares to study images from a magnetic resonance imaging (MRI) scanner at the Ambroise Pare hospital in Marseille, southern France

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