Usefulness of arterial spin-labeling images in periictal state diagnosis of epilepsy.

PURPOSE: Arterial spin-labeling (ASL) perfusion MRI, a noninvasive method of assessing cerebral blood flow, is becoming a diagnostic tool of epilepsy. This study was undertaken to evaluate the diagnostic validity of ASL in patients with status epilepticus (SE) in a periictal state.

METHOD: Twenty cases with SE were studied. Patients were imaged at a 3T MRI including ASL and diffusion-weighted imaging (DWI), and were also examined using electroencephalography (EEG). The abnormal findings of ASL were compared with those obtained from DWI and EEG.

RESULT: Focal hyperperfusion was found in the cortical territory of 13 cases (65%). In 10 of those 13 cases, the ASL hyperperfusion region corresponded to DWI high intensity and EEG abnormality. Two cases showed hyperperfusion corresponding to EEG abnormalities in ASL despite the absence of high intensity in DWI. The remaining single case showed hyperperfusion in ASL despite the absence of high intensity in DWI and EEG abnormalities. Hyperperfusion in the subcortical territory was observed in the ipsilateral thalamus in three cases and in the contralateral cerebellum in one case.

CONCLUSION: Our results suggest that ASL is a useful tool to diagnose status epilepticus and localization of the epilepsy focus.