fMRI in patients implanted with a vagal nerve stimulator.
OBJECTIVE
To demonstrate the feasibility and safety of using functional magnetic resonance imaging (fMRI) to determine the blood oxygen level dependent changes (BOLD) in patients undergoing vagal nerve stimulation (VNS) for the treatment of epilepsy.


METHODS
Four patients with an implanted vagus nerve stimulator had fMRI images acquired during several cycles of intermittent VNS. Blood oxygen level dependent changes were detected. These regions were then superimposed upon the patients' structural MR images.


RESULTS
Patients undergoing VNS tolerated fMRI without difficulty. No complications with the implanted stimulators were encountered. Areas of activation were noted in several cortical regions, including frontal, temporal, parietal, and occipital cortices.


CONCLUSIONS
Our study in four patients shows fMRI can be performed safely in patients with an implanted vagal nerve stimulator. The successful use of fMRI during VNS offers potential advantages over PET imaging by allowing rapid image acquisition and the ability to repeatedly study patients over time. Our preliminary results differ from previous PET or SPECT studies in failing to detect changes in subcortical areas. This finding could be due to the smaller n in this study compared with the other studies.
Sucholeiki
Roy
R
Department of Neurology, Medical College of Wisconsin-Milwaukee, WI, USA.
Alsaadi
Taoufik M
TM
Morris
George L
GL
Ulmer
John L
JL
Biswal
Bharat
B
Mueller
Wade M
WM
D000328:Adult; D001931:Brain Mapping; D004558:Electric Stimulation; D004827:Epilepsy / Q000503:physiopathology / Q000628:therapy*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010865:Pilot Projects; D014630:Vagus Nerve
D010100:Oxygen