Various Pathophysiological States Of Acute Symptomatic Seizures Immediately After Ischemic Stroke, Namely "Onset Seizures," Shown By Complementary Use Of Peri-Ictal Magnetic Resonance Imaging And Electroencephalography

Background: "Onset seizures" are acute symptomatic seizures occurring within 24 h after the onset of ischemic stroke, and their pathophysiological states are unknown. Electroencephalography is commonly used to diagnose epileptic activities; however, it is limited for use with acute stroke. Magnetic resonance imaging, including diffusion-weighted imaging and perfusion imaging with arterial spin labeling, are applied mainly in an emergency. Ictal hyperperfusion on arterial spin labeling and cortical hyperintensity of cytotoxic edema on diffusion-weighted imaging, peri-ictally, can be obtained from an epileptically activated cortex.Aim: We aimed to show pathophysiological states of onset seizures by complementary use of peri-ictal magnetic resonance imaging and electroencephalography.Methods: Four patients diagnosed as onset seizures underwent an initial magnetic resonance imaging and subsequent electroencephalography.Results: In case 1, having persistent non-convulsive status epilepticus after control of onset seizures, ictal magnetic resonance imaging and electroencephalography findings clearly showed the topographical relationship between the acute atherothrombotic infarction and the peri-infarction activated cortex. In case 2, with multiple embolic strokes in the bifrontal lobes, prolonged arterial spin labeling hyper signals were observed in the perirolandic area of the right leg; cortical hyperintensity on diffusion-weighted imaging and paroxysmal activities on electroencephalography were not shown. In cases 3 and 4, postictal hypoperfusion was shown in the large extent involving the multiple embolic infarctions. Because the epileptic cortex was located in the convexity, electroencephalography clearly showed inter-ictal paroxysms in case 3, and localized slow wave in case 4.Conclusion: The present study shows that the complementary use of peri-ictal arterial spin labeling/diffusion-weighted imaging and electroencephalography potentially offers the ability to document the various pathophysiological states of onset seizure.