IBCN   20355
INSTITUTO DE BIOLOGIA CELULAR Y NEUROCIENCIA "PROFESOR EDUARDO DE ROBERTIS"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
An open source toolbox for intracranial grid and depth electrodes localization and anatomical labeling
Autor/es:
BLENKMANN ALEJANDRO; PHILLIPS HOLLY; PRINCICH JUAN PABLO; KOCHEN SILVIA
Lugar:
Estambul
Reunión:
Congreso; 31st International Epilepsy Congress; 2015
Institución organizadora:
ILAE
Resumen:
Purpose:During intracranial EEG recordings for the presurgical evaluation of patients with drug resistant epilepsy, it is of critical importance to know the exact localization of the electrodes and their anatomical description. Here we present an open source toolbox (https://sourceforge.net/projects/ielectrodes/) to obtain the coordinates of each electrode in a semiautomatic way with minimal user intervention.Method:Six patients implanted with grids and depth electrodes were studied. Post implantation T1 MRI and CT were coregistered using an affine transformation with SPM8 toolbox (http://www.fil.ion.ucl.ac.uk/spm/software/spm8/). Subject-specific cortical segmentation labels were obtained using Freesurfer software (http://surfer.nmr.mgh.harvard.edu/). Brain masks were obtained using FSL-BET software (http://fsl.fmrib.ox.ac.uk/fsl/fslwiki/BET). In order to work within a normalized space (optional), T1 MRI and CT were coregistered to the MNI-152 space using a brain mask and nonlinear warping deformations with SPM8. All images were loaded in NIfTI format to our Matlab (http://www.mathworks.com/products/matlab/) based toolbox.Electrode voxels were detected by using a dilated brain mask and thresholding high intensity CT voxels in a 3D reconstruction[1]. User intervention was needed to determine the threshold and dilation levels. Then, these voxels were automatically clustered and the electrode coordinates were obtained. Electrodes were numbered and an anatomical label was assigned automatically to each one. A 3D view of electrodes over a semitransparent brain was shown for visual interpretation. CT and MRI sagittal, coronal, and axial views of electrode coordinates were visually checked by an expert. A report (.txt file) with each electrode?s information was made automatically. Results:Six patients were studied with 104, 332 SEEG, or ECoG electrodes. In all cases, electrode coordinates were successfully located within visualized electrodes artifact in CT and MRI images.Conclusions:The proposed tool is a useful and easy-to-use instrument to achieve a fast and robust localization and labeling of intracranial electrodes.