Cortical Localization of Scalp Electrodes on Three-Dimensional Brain Surface Using Frameless Stereotactic Image Guidance System

J Korean Neurol Assoc > Volume 25(2); 2007 > Article

Journal of the Korean Neurological Association 2007;25(2): 155-160.

Frameless Stereotactic Image Guidance System을 이용한 대뇌 피질상의 두피 전극의 국소화

김대영, 주은연 태우석 한선정* 조재욱 서대원 홍승봉

성균관대학교 의과대학 삼성서울병원 신경과, 원광대학교 의과대학 산본병원 신경과*

Cortical Localization of Scalp Electrodes on Three-Dimensional Brain Surface Using Frameless Stereotactic Image Guidance System

Daeyoung Kim

Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, *Department of Neurology, Sanbon Medical Center, College of Medicine, Wonkwang University

Abstract

Background: The purpose of this study was to localize the cortical regions reflected by overlying scalp electrodes.
Methods: We enrolled 10 patients with epilepsy (5 males, mean age 29.7 years old). Thin slice coronal T1 weighted MR images were obtained and then scalp EEG electrodes were placed based on an international 10-20 system. Cortical locations of scalp electrodes were determined using a real-time frameless stereotactic image guidance system, Brainsight?.
Results: The locations of 19 scalp electrodes were marked on the 3D rendered cortical surface of one representative patient’s MRI; Fp1 (Fp2) on the anterior pole of the middle frontal gyrus, Fz on the mid-point of the interhemispheric fissure in the frontal lobe, F3 (F4) on the mid-portion of the middle frontal gyrus, F7 (F8) on the pars triangularis of the inferior frontal gyrus, Cz on the interhemispheric fissure where a lateral precentral gyrus starts, C3 (C4) scattered around postcentral gyrus, T3 (T4) on the middle temporal gyrus, P3 (P4) on the angular gyrus, Pz on the mid-point of the interhemispheric fissure in the parietal lobe, T5 (T6) on the posterior part of the inferior temporal gyrus, and O1 (O2) on the occipital pole.
Conclusions: The locations of scalp electrodes were well correlated with conventional concepts of their cortical locations. The individual differences of the scalp electrode locations may be due to the different sizes and morphologies of the brains in each of the patients. Real time cortical localization of scalp electrodes using the Frameless Stereotactic Image Guidance System may provide useful information for more accurate localization of focal cerebral activity in partial epilepsy patients. KeyWords:Frameless stereotaxy, Scalp electrodes, EEG, MRI