MRI Captures Alzheimer's Lesions (HealthDay)

SUNDAY, July 27 (HealthDay News) -- Scientists are reporting that theyhave captured images of brain lesions in rabbits similar to those found inpeople with Alzheimer's disease using conventional MRIs.

Amyloid plaques, which accumulate in the brain and are a hallmark ofAlzheimer's, have been captured before through extra-high-power MRIscanners meant for use in animals and with PET scans.

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

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

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

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

"This technology is not directly translatable to human imaging, but wefeel this might inspire other people to consider this approach," Ronaldsaid. "We're starting to explore the building of new hardware and theability to potentially do this one day in humans."

"There has been a lot of effort to look at atrophy or shrinkage of thebrain with MRI scans in patients with Alzheimer's disease, and we do knowthat the brain shrinks as disease progresses," said Dr. Scott Turner,incoming director of the Memory Disorders Program at Georgetown UniversityMedical Center in Washington, D.C., "This is a new approach, [but] it'smuch easier to do when the brain is smaller such as in a mouse or arabbit."

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

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

In related news also being presented Sunday at the conference:

• Researchers at the Mayo Clinic in Rochester, Minn., confirmed that anew MRI analysis algorithm could capture the severity of another hallmarkof Alzheimer's disease, neurofibrillary tangles, in the brain. The methodcould one day be used for earlier diagnosis of the disease.
• University of Pennsylvania investigators found that "Alzheimer's-likepatterns" of brain atrophy or shrinkage were more common in individualsover the age of 80. These patterns also developed faster the older anindividual became. It's unclear how these patterns might correlate withactual cognitive function, but researchers are hopeful that this mayprovide a way to detect early brain changes related to Alzheimer's.
• Two more Mayo Clinic studies concluded that multiple different imagingtechniques, such as MRI, magnetic resonance (MR) spectroscopy, and 11CPittsburgh Compound B each contribute information about a person'scognitive function. Using the techniques together would give a morecomplete picture than using each alone.

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