http://www.technologyreview.com/biomedicine/16971/?mod=related&a=f


Biomedicine

New Imaging Techniques Find Hidden Scars in Brain

Arrays of MRI detectors could help doctors pinpoint the tiny structural
flaws behind epilepsy and other disorders.
Friday, June 9, 2006
By Emily Singer

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As the fetal brain develops, new neurons are born and migrate to different
parts of the brain, forming the complex and highly ordered structure of the
cerebral cortex. But every now and again, that process goes awry. Sometimes
tiny architectural glitches in the cortex lead to big problems, such as the
uncontrolled electrical storms in the brain that underlie seizures. 


Now higher-resolution brain-imaging technologies could help doctors find
these hidden flaws, allowing surgeons to remove the damaged area -- and
giving scientists new insight into the causes of epilepsy. 






Epilepsy is characterized by recurring seizures, caused by uncontrolled
waves of electrical activity that propagate throughout the brain. About
two-thirds of epilepsy patients can control the disease with drugs. The
remaining third can sometimes undergo surgery to remove the tiny section of
brain tissue that sparks seizures -- but only if surgeons can find the
offending spot with a brain scan. 


Scientists estimate that about 25 percent of these patients have tiny
abnormalities -- which likely originated during cortical development -- that
are too subtle to be detected with traditional brain imaging. But new
imaging technologies, such as those being developed by researchers at the
Martinos Center for Biomedical Imaging at Massachusetts General Hospital
(MGH) in Boston, are bringing relief to these patients. In a study released
last fall, Ellen Grant, chief of pediatric neuroradiology at MGH, and
colleagues were able to detect lesions in about two-thirds of epileptic
patients whose previous brain scans had been declared normal, making these
patients better candidates for neurosurgery. The team is now engineering
even higher-resolution devices, which they'll use to study learning
disabilities and other developmental disorders, such as autism. 


"This technology is a very good improvement over previous high-resolution
technologies," says Imad Najm, an epilepsy expert at the Cleveland Clinic in
Ohio. "It will allow us to see some lesions we did not see before and to see
bigger lesions where we could see only smaller ones, lesions which were just
the tip of the iceberg."


With traditional magnetic resonance imaging (MRI), a large magnet is coupled
with a radio-frequency detector that picks up characteristic signals from
different tissues in the brain, generating a detailed picture of the brain's
structure. Scientists are now developing devices that use arrays of anywhere
from 8 to 256 detectors to get higher-resolution images of the brain. "It's
like a compound eye for MRI," says Bruce Rosen, director of the Martinos
Center.

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