Magnetic resonance imaging in localization of EEG depth electrodes for seizure monitoring

Preoperative evaluation of patients with medically refractory complex partial seizures requires intensive EEG monitoring. Part of this process may include insertion of depth electrodes into temporal lobe structures. Although many imaging methods have been used for stereotactic placement of the electrodes, only computed tomography (CT) has been used to verify position after implantation. We studied 30 patients in whom magnetic resonance imaging (MRI) was used to visualize the position of stainless-steel electrodes stereotactically implanted in the temporal lobes. The procedure is noninvasive, does not utilize radiation, and has the additional advantages of multiplanar capability, increased soft tissue contrast, and lack of bony artifacts commonly associated with CT.