Diffusion-weighted imaging and status epilepticus during vagus nerve stimulation.
OBJECTIVE
Transient abnormalities have been reported on diffusion-weighted imaging (DWI) during status epilepticus. Vagus nerve stimulation (VNS) is a therapy for epilepsy that has previously demonstrated alteration in regional cerebral blood flow on functional neuroimaging. We describe the peri-ictal DWI abnormalities in a patient with status epilepticus.


METHODS
A 21-year-old woman with pharmacoresistant localization-related epilepsy was treated with VNS and underwent brain magnetic resonance imaging (MRI) with DWI for clinical purposes.


RESULTS
Transient and reversible hyperintense signal abnormalities were noted on DWI at the site of seizure onset, in addition to the thalamus and midbrain bilaterally. A concomitant decrease in the apparent diffusion coefficient mimicked ischemia, yet complete clinical, and electrographic resolution occurred following successful termination of status.


CONCLUSIONS
High-energy brain MRI sequences using DWI were safely performed in our epilepsy patient with a vagus nerve stimulator who experienced status epilepticus. This case highlights the bilateral and robust involvement of subcortical structures present immediately following status epilepticus. Additionally, bilateral abnormalities in the thalamus and midbrain in addition to the region of seizure origin, were observed in our patient implanted with a vagus nerve stimulator. Modulation of regional cerebral blood flow is one potential mechanism of action for VNS in humans; therefore, these regions of involvement could reflect the effects of status epilepticus, activation or facilitation by VNS, or both.
Tatum
W O
WO
Department of Neurology, University of South Florida, Tampa, FL, USA. wotiv@aol.com
Malek
A
A
Recio
M
M
Orlowski
J
J
Murtagh
R
R
D000328:Adult; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004599:Electric Stimulation Therapy / Q000379:methods*; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D013226:Status Epilepticus / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome; D014630:Vagus Nerve / Q000528:radiation effects*