IMPROVED MRI AND INTRACTRANIAL EEG CORRELATION USING BRAINLAB PROTOCOL IN PEDIATRIC PATIENTS WITH CORTICAL DYSPLASIA
Abstract number :
1.420
Submission category :
Year :
2003
Submission ID :
3791
Source :
www.aesnet.org
Presentation date :
12/6/2003 12:00:00 AM
Published date :
Dec 1, 2003, 06:00 AM
Authors :
Robert Flamini, Roger Hudgins, Susan Palasis, Raymond Cheng, Brian Philbrook, Jennifer Ganote, Thomas Burns, Lynne Gilreath Children[apos]s Epilepsy Center, Children[apos]s Hospital of Atlanta at Scottish Rite, Atlanta, GA
Adequate electrode coverage of areas of abnormal cortical signal on MRI is essential when considering intracranial recordings for intractable epilepsy. Despite clear signal changes on MRI, the brain surface is commonly normal at the time of subdural electrode placement, particularly in children with cortical dysplasias. The BrainLab Imaging System improves accuracy for placement of recording electrodes.
Four pediatric patients (ages 6 months to 8 years ) underwent intracranial recordings ( three extraoperatively, one intraoperatively) for delineation of epileptogenic zone utilizing MRI guided stereotactic placement with the BrainLab Computer Assisted Image Guided System. MRI images were acquired using 3D FSPGR T1 sequence, T2 and FLAIR pre operatively, and taken to the operating room for navigation using Laser Z-point guided coregistration with accuracy of 1.6 to 2 mm. Extraoperative cortical stimulation was completed to delineate eloquent cortex. Resection and multiple subpial transections were tailored for each patient.
All patients had excellent agreement between electrical and anatomical abnormalities based on stereotactic guided electrode placement. Both interictal and ictal recordings were located over the grid in the expected area of MRI abnormality based on laser guided coregistration. This technique proved placement of the subdural electrodes was directly over the area of anatomical abnormality. The correlation between MRI and EEG allowed adequate delineation of epileptogenesis, followed by a tailored resection. This is reflected in excellent outcome in 3 out of 4 patients (Engel IA, IB). The patient with poor outcome proved later to have Rasmussen[rsquo]s encephalopathy, and underwent a functional hemispherectomy. Pathology confirmed cortical dysplasia in all patients, one of whom had co-diagnosis of Tuberous Sclerosis.
MRI guided stereotactic placement of subdural electrodes utilizing BrainLab protocol greatly improves correlation between MRI abnormalities and interictal as well as ictal EEG changes. Given the common normal appearance of cortical surface at the time of electrode placement, we currently use and recommend this technique to improve correlation between MRI and EEG for localization of ictal onset.