For about a third of epilepsy patients, drugs don't work. Surgery is the next hope for a cure -- but that depends on identifying the problematic spot in the brain. According to a new study, an imaging technique in development at the University of Pennsylvania offers a better way for doctors to treat patients with the disease.
The method, described in the journal Science Translational Medicine, is a kind of modified MRI that measures levels of the neurotransmitter glutamate in the brain.
"From a patient's perspective, it's not much different from a typical MRI scan," said Penn epilepsy specialist Kate Davis, who led the study. But preliminary results suggest the technology has a clear edge over its traditional counterpart.
When researchers tested the method on four patients whose regular MRIs had come up blank, the scans correctly located abnormal tissue on one side of the hippocampus.
Davis said that increased visibility might one day improve surgical outcomes.
"Often we're concerned that we're only seeing the tip of the icebergs," she said. "Even those with lesions on their imaging, you might not be capturing the whole functional network around that lesion."
The technique could also cut down on the need to insert electrodes in the brain to better visualize the areas responsible for triggering seizures.
In that regard, Thomas Jefferson University neurologist Michael Sperling, who was not involved in the research, said the new method might prove to be a real advance.
But how useful the scan will be for the trickiest patients, he said, remains to be seen.
"Does this give us confidence to be able to offer surgery in those individuals?" he said. "Or is the yield not as great? And that's what we'll have to see."
Other ways of measuring glutamate already exist, but they are either invasive or time consuming and have poor resolution, said Penn radiologist Ravinder Reddy, who was the senior author on the work.
"This is a very high[ly] sensitive method," he said, noting that it is at least 100 times better than traditional magnetic resonance spectroscopy.
Since the technique was evaluated in just a few patients, more testing is needed before it is used in the clinic. The scans require an extra powerful magnet that is not yet approved by the FDA and is available only in certain academic research centers.