New Method for Triggering and Imaging Seizures to Help Guide Epilepsy Surgery

In comparison to the previous approach, where physicians from neurology and nuclear medicine waited for hours to days to capture the onset of a seizure, the new method developed by researchers at University Hospital of Bern (Bern, Switzerland), is more convenient, requires fewer resources, and is clinically feasible. In their study involving three adult subjects with left temporal lobe epilepsy, the researchers decided not to wait for spontaneous occurrences and instead imaged planned seizures that were triggered with targeted electrical stimulation to the brain. The research team employed stereotactic electroencephalography (sEEG) leads placed in specific brain regions to induce seizures characteristic of each patient. A radiotracer, 99mTc-HMPAO, was administered within 12 seconds of the seizure's start, with SPECT imaging following within 40 minutes.

The method successfully triggered seizures in all the participants, replicating each patient's typical seizure presentation and electrographic pattern observed through sEEG, without causing any adverse effects. The seizures induced were specific for each patient, with early seizure spread being uniquely imaged. In the first two cases, ictal SPECT provided additional insights beyond those offered by sEEG, highlighting the early involvement of brain regions lacking electrode coverage. In the third case, both sEEG and ictal SPECT provided overlapping information.

“The finding of this study is of practical nature, as it greatly facilitates the acquisition of the ictal SPECT,” said Thomas Pyka, MD, Privatdozent in the Department of Nuclear Medicine at the University Hospital of Bern. “This may help obtain images of greater quality and could contribute to the refinement of resection planning, improving seizure and cognitive outcomes in epilepsy surgery.”

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