by Brendon Nafziger
, DOTmed News Associate Editor | August 04, 2011
A rare, expensive, ultra-high-field research MRI shows promise at finding scarring in the brain that could trigger epilepsy attacks.
Most MRI scans are done with 1.5- or 3-Tesla devices. But researchers at the University of Minnesota Medical School say the improved spatial resolution and contrast from a 7-Tesla scanner could help reveal changes to the brain too subtle to be picked up by currently available systems.
"We're expecting the rise in spatial resolution will be translated into a lot of advantages in the brain," Dr. Thomas Henry, a professor of neurology at the university who led the study, tells DOTmed News by phone.
Research purposes only
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The university's Center for Magnetic Resonance Research, in Minneapolis, where the study was conducted, has two 7-T machines. One was built in house and has been owned by the center for nearly a decade. The other was purchased from Siemens, which along with Philips and GE is one of the main vendors of the experimental units. (The center also houses a whopping 16.4-T machine.)
Experts estimate around 40 7-Tesla MRIs are installed worldwide, mostly in research centers. None has ever been cleared by the Food and Drug Administration for routine clinical use.
Henry says 7-T's strengths likely lie in "finding small, early abnormalities so [patients] could have surgical treatment before conditions become advanced." For instance, with better resolution, doctors could discover a small tumor before it has time to grow and cause massive brain injuries.
In the study, published online ahead of print last month in the journal Radiology, researchers used the 7-T scanner to try to identify subtle evidence of brain changes linked with a type of epilepsy called temporal lobe epilepsy.
One of the more common forms of partial epilepsy, temporal lobe epilepsy causes seizures thought to originate in the hippocampus, a long, thin structure nestled deep within the brain's two temporal lobes. About 3 million Americans suffer from epilepsy, according to the Epilepsy Foundation, although the exact number suffering from temporal lobe epilepsy is unknown.
The condition can often be treated with medication. But if patients don't respond to drugs, doctors can surgically remove scar tissue to control seizures. But Henry says not all patients are good candidates for surgery, and MRI scans are used to identify abnormal structures in the brain that can be safely treated.
But it's a challenge to analyze the hippocampus, a major memory center of the brain, which is also implicated in Alzheimer's disease. It's quite small, about a half-inch-wide, "no wider than the end of a person's little finger," Henry says.