Detection of subtle periictal hyperperfusion with 1.5-Tesla arterial spin labeling perfusion imaging in a patient with congenital unilateral perisylvian syndrome in a neurological emergency

Abstract

We made a pathophysiological diagnosis of epileptic seizures in a 50-year-old male with congenital unilateral perisylvian syndrome due to right perisylvian polymicrogyria, using routine electroencephalography (EEG) and 1.5-Tesla arterial spin labeling (ASL) magnetic resonance perfusion imaging. No paroxysmal discharges were recorded on EEG performed 1 h after the generalized convulsive seizure. Pseudo-continuous and pulsed ASL images taken 1 h 30 min and 1 h 15 min after the seizure, respectively, captured subtle periictal hyperperfusion linked to seizure activity via neurovascular coupling at the perisylvian area. In particular, the fusion of ASL images with the sagittal view of a three-dimensional T1-weighted image clearly revealed periictal hyperperfusion at the area of polymicrogyria, indicating intrinsic epileptogenicity. This case report details how adding ASL to routine EEG data can be useful in the pathophysiological diagnosis of epilepsy in neurological emergencies.