TY - JOUR
T1 - Volumetric localization of epileptic activity using wavelet-based synthetic aperture magnetometry
AU - Xiang, Jing
AU - Wang, Yingying
AU - Xiao, Zheng
AU - Balioussis, Christina
AU - Zhu, Hongmei
AU - Holowka, Stephanie
AU - Sharma, Roy
AU - Hunjan, Amrita
AU - Otsubo, Hiroshi
AU - Chuang, Sylvester
PY - 2007/6
Y1 - 2007/6
N2 - To go beyond using magnetoencephalography (MEG) for visual identification of epileptic spikes, this study was to quantitatively estimate epileptic spectral power and volumetrically localize the neuromagnetic activity associated with epilepsy. MEG data were recorded from 16 patients with epilepsy using a whole-cortex MEG system. Focal increases of spectral power were identified using wavelet; the three-dimensional neuromagnetic distributions of the focal increases of spectral power were estimated using synthetic aperture magnetometry (SAM). SAM images and dipoles pointed to a same area in 12 patients (75% 12/16), SAM revealed focal epileptic activity but dipole modelling failed in 2 patients (12.5%, 2/16), and SAM detected more epileptic foci than dipole modelling did in 2 patients (12.5%, 2/16). Interestingly, spectrogram revealed focal increases of spectral power just before magnetic spikes; and SAM peaks were close to the dipoles of the initial portion of the spikes. The results suggest that wavelet-based SAM analysis has the potential to localize the onset of epileptic seizures, and seems superior to dipole modelling for estimation of multiple epileptic foci. In comparison to the conventional visual identification of spike, wavelet-based SAM analysis is objective and quantitative. Thus, wavelet-based SAM analysis has the potential to be extremely useful for clinical management of epilepsy.
AB - To go beyond using magnetoencephalography (MEG) for visual identification of epileptic spikes, this study was to quantitatively estimate epileptic spectral power and volumetrically localize the neuromagnetic activity associated with epilepsy. MEG data were recorded from 16 patients with epilepsy using a whole-cortex MEG system. Focal increases of spectral power were identified using wavelet; the three-dimensional neuromagnetic distributions of the focal increases of spectral power were estimated using synthetic aperture magnetometry (SAM). SAM images and dipoles pointed to a same area in 12 patients (75% 12/16), SAM revealed focal epileptic activity but dipole modelling failed in 2 patients (12.5%, 2/16), and SAM detected more epileptic foci than dipole modelling did in 2 patients (12.5%, 2/16). Interestingly, spectrogram revealed focal increases of spectral power just before magnetic spikes; and SAM peaks were close to the dipoles of the initial portion of the spikes. The results suggest that wavelet-based SAM analysis has the potential to localize the onset of epileptic seizures, and seems superior to dipole modelling for estimation of multiple epileptic foci. In comparison to the conventional visual identification of spike, wavelet-based SAM analysis is objective and quantitative. Thus, wavelet-based SAM analysis has the potential to be extremely useful for clinical management of epilepsy.
KW - Epilepsy
KW - High frequency
KW - Magnetoencephalography
KW - Neuromagnetic signals
KW - Synthetic aperture magnetometry (SAM)
KW - Wavelet
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U2 - 10.1016/j.ics.2007.03.003
DO - 10.1016/j.ics.2007.03.003
M3 - Article
AN - SCOPUS:34250021410
SN - 0531-5131
VL - 1300
SP - 697
EP - 700
JO - International Congress Series
JF - International Congress Series
ER -