title: fMRI in patients implanted with a vagal nerve stimulator.
abstract: 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.
authors.affiliation: Department of Neurology, Medical College of Wisconsin-Milwaukee, WI, USA.
authors.forename: Roy
authors.initials: R
authors.lastname: Sucholeiki
authors.forename: Taoufik M
authors.initials: TM
authors.lastname: Alsaadi
authors.forename: George L
authors.initials: GL
authors.lastname: Morris
authors.forename: John L
authors.initials: JL
authors.lastname: Ulmer
authors.forename: Bharat
authors.initials: B
authors.lastname: Biswal
authors.forename: Wade M
authors.initials: WM
authors.lastname: Mueller
mesh_terms: 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
chemical_list: D010100:Oxygen