Epilepsy Can’t Hide From Seven-Tesla MRI

August 3, 2011

Magnetic resonance imaging (MRI) with 7-Tesla ultrahigh-field-strength technology captures scar tissue and other abnormalities of patients with epilepsy, according to a study published online in the journal Radiology.

Magnetic resonance imaging (MRI) with 7-Tesla ultrahigh-field-strength technology captures scar tissue and other abnormalities of patients with epilepsy, according to a study published online in the journal Radiology.

A University of Minnesota team led by neurologist Thomas Henry, MD, used a 7-T magnet operated from a Siemens console and a 16-detector head coil to image the brains of 11 healthy subjects and eight patients with temporal lobe epilepsy (TLE). Typical MRI magnets are powered at 1.5 or 3 Teslas.

Epilepsy, a neurological disorder causing repeated seizures or convulsions, impacts about 1 percent of the population, according to the National Institutes of Health. Temporal lobe epilepsy is the most common form of the disease, caused by scarring inside the hippocampus, a major memory center of the brain. Many patients have severe memory problems, even in between seizures.

The team reviewed the MRIs for evidence of hippocampal atrophy, signal change, and malrotation with the Bernasconi definition. They also counted digitations of the hippocampal heads. All eight patients with epilepsy had hippocampal abnormalities. Closer analysis showed selective lateral Ammon horn atrophy in six patients and diffuse Ammon horn and dentate gyrus atrophy in one patient. The epileptic patients lacked hippocampal digitations on the seizure-causing brain hemisphere.

The clearer MRI images allowed Henry and his colleagues to more accurately find scar tissue associated with temporal lobe epilepsy, which neurosurgeons can remove to control epileptic seizures.

“When you see how much clearer these 7 Tesla images are, compared with standard MRI, it’s sort of like reading fine print with a magnifying glass versus the naked eye,” Henry said. “The possibility of using 7-Tesla MRI to find brain lesions that were missed on current brain scans is likely to be very helpful in epilepsy and many other conditions.”