Bioethics Blogs

Brain Imaging: Advance Aims for Epilepsy’s Hidden Hot Spots

Caption: GluCEST imaging of the brain of a person with drug-resistant epilepsy, showing the hippocampi (highlighted) with signal for high glutamate (red).
Credit: Reddy Lab, University of Pennsylvania

For many of the 65 million people around the world with epilepsy, modern medications are able keep the seizures under control. When medications fail, as they do in about one-third of people with epilepsy, surgery to remove affected brain tissue without compromising function is a drastic step, but offers a potential cure. Unfortunately, not all drug-resistant patients are good candidates for such surgery for a simple reason: their brains appear normal on traditional MRI scans, making it impossible to locate precisely the source(s) of the seizures.

Now, in a small study published in Science Translational Medicine [1], NIH-funded researchers report progress towards helping such people. Using a new MRI method, called GluCEST, that detects concentrations of the nerve-signaling chemical glutamate in brain tissue [2], researchers successfully pinpointed seizure-causing areas of the brain in four of four volunteers with drug-resistant epilepsy and normal traditional MRI scans. While the findings are preliminary and must be confirmed by larger studies, researchers are hopeful that GluCES, which takes about 30 minutes, may open the door to new ways of treating this type of epilepsy.

To understand why glutamate might be a useful marker for epilepsy, it’s useful to note that this molecule serves as the brain’s main excitatory nerve signal. In healthy people, when neurons fire off a stimulatory signal, they release short bursts of glutamate to relay the signal onward. Support cells then rapidly clear the glutamate.

The views, opinions and positions expressed by these authors and blogs are theirs and do not necessarily represent that of the Bioethics Research Library and Kennedy Institute of Ethics or Georgetown University.