B-14. Pathophysiological diagnosis of status epilepticus with complementary use of the periictal MRI (arterial spin labeling perfusion and diffusion-weighted images) and EEG

Abstract

In the diagnosis of nonconvulsive status epilepticus (NCSE), capture of ongoing ictal EEG findings is the gold standard; however, this is practically difficult without continuous EEG monitoring facilities. MRI, including diffusion-weighted imaging (DWI) and perfusion MRI with arterial spin labeling (ASL), have been applied mainly in emergency situations. Recent reports have described that ictal MRI findings, including ictal hyperperfusion on ASL and cortical hyperintensity of cytotoxic edema on DWI, can be obtained from epileptically activated cortex. We demonstrate the diagnostic value of ictal MRI findings in 15 patients diagnosed as having NCSE (eight had complex partial status epilepticus (SE) and seven subtle SE) who underwent an initial MRI and subsequent routine EEG. In all 10 patients with an epileptogenic lesion, there was a tight topographical relationship between the lesion and the localization of ictal MRI findings. In the other five patients, ictal MRI findings were useful in the diagnosis of NCSE of non-lesional elderly epilepsy, or de novo NCSE of frontal origin as situation-related NCSE. The present study clearly demonstrates that the initial use of ASL and DWI has the ability to diagnose partial NCSE and also allows documentation of the pathophysiological mechanism in each patient.