<abstract xmlns="http://www.w3.org/1999/xhtml"><p> This work was performed as part of a larger research concerning the feasibility of improving the localization of epileptic foci, as compared to the standard SPECT examination, by applying the technique of EEG mapping. The presented study extends our previous work on the development of a method for superposition of SPECT images and EEG 3D maps when these two examinations are performed simultaneously. Due to the lack of anatomical data in SPECT images it is a much more difficult task than in the case of MRI/EEG study where electrodes are visible in morphological images. Using the appropriate dose of radioisotope we mark five base electrodes to make them visible in the SPECT image and then approximate the coordinates of the remaining electrodes using properties of the 10-20 electrode placement system and the proposed nine-ellipses model. This allows computing a sequence of 3D EEG maps spanning on all electrodes. It happens, however, that not all five base electrodes can be reliably identified in SPECT data. The aim of the current study was to develop a method for determining the coordinates of base electrode(s) missing in the SPECT image. The algorithm for coordinates approximation has been developed and was tested on data collected for three subjects with all visible electrodes. To increase the accuracy of the approximation we used head surface models. Freely available model from Oostenveld research based on data from SPM package and our own model based on data from our EEG/SPECT studies were used. For data collected in four cases with one electrode not visible we compared the invisible base electrode coordinates approximation for Oostenveld and our models. The results vary depending on the missing electrode placement, but application of the realistic head model significantly increases the accuracy of the approximation.</p></abstract>

This work was performed as part of a larger research concerning the feasibility of improving the localization of epileptic foci, as compared to the standard SPECT examination, by applying the technique of EEG mapping. The presented study extends our previous work on the development of a method for superposition of SPECT images and EEG 3D maps when these two examinations are performed simultaneously. Due to the lack of anatomical data in SPECT images it is a much more difficult task than in the case of MRI/EEG study where electrodes are visible in morphological images. Using the appropriate dose of radioisotope we mark five base electrodes to make them visible in the SPECT image and then approximate the coordinates of the remaining electrodes using properties of the 10-20 electrode placement system and the proposed nine-ellipses model. This allows computing a sequence of 3D EEG maps spanning on all electrodes. It happens, however, that not all five base electrodes can be reliably identified in SPECT data. The aim of the current study was to develop a method for determining the coordinates of base electrode(s) missing in the SPECT image. The algorithm for coordinates approximation has been developed and was tested on data collected for three subjects with all visible electrodes. To increase the accuracy of the approximation we used head surface models. Freely available model from Oostenveld research based on data from SPM package and our own model based on data from our EEG/SPECT studies were used. For data collected in four cases with one electrode not visible we compared the invisible base electrode coordinates approximation for Oostenveld and our models. The results vary depending on the missing electrode placement, but application of the realistic head model significantly increases the accuracy of the approximation.

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

Nałęcz Institute of Biocybernetics and Biomedical Engineering PAS, Department of Neuroengineering, Ks. Trojdena 4 str., 02-109 Warsaw, Poland

Medical University of Warsaw, Department of Nuclear Medicine, Banacha 1a str., 02-097 Warsaw, Poland

Measurement Science Review

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

This work was performed as part of a larger research concerning the feasibility of improving the localization of epileptic foci, as compared to the standard...

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

Published Online: May 08, 2014

Page range: 109 - 116

Received: Jul 31, 2013

Accepted: Apr 11, 2014

DOI: https://doi.org/10.2478/msr-2014-0015

Keywords
EEG electrodes, SPECT, multimodal co-registration, EEG mapping, BioImage Suite, 3D image reconstruction

© by L. Kowalczyk

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Invisible Base Electrode Coordinates Approximation for Simultaneous SPECT and EEG Data Visualization

Published Online: May 08, 2014

Page range: 109 - 116

Received: Jul 31, 2013

Accepted: Apr 11, 2014

DOI: https://doi.org/10.2478/msr-2014-0015

KeywordsEEG electrodes, SPECT, multimodal co-registration, EEG mapping, BioImage Suite, 3D image reconstruction

© by L. Kowalczyk

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Keywords
EEG electrodes, SPECT, multimodal co-registration, EEG mapping, BioImage Suite, 3D image reconstruction