National Society for Epilepsy MRI Unit, Department of Clinical and Experimental Epilepsy UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London, WC1N 3BG, UK.
Neuroimage. 2010 Feb 15;49(4):3219-29. doi: 10.1016/j.neuroimage.2009.11.055. Epub 2009 Dec 4.
EEG-correlated fMRI (EEG-fMRI) studies can reveal haemodynamic changes associated with Interictal Epileptic Discharges (IED). Methodological improvements are needed to increase sensitivity and specificity for localising the epileptogenic zone. We investigated whether the estimated EEG source activity improved models of the BOLD changes in EEG-fMRI data, compared to conventional << event-related >> designs based solely on the visual identification of IED.
Ten patients with pharmaco-resistant focal epilepsy underwent EEG-fMRI. EEG Source Imaging (ESI) was performed on intra-fMRI averaged IED to identify the irritative zone. The continuous activity of this estimated IED source (cESI) over the entire recording was used for fMRI analysis (cESI model). The maps of BOLD signal changes explained by cESI were compared to results of the conventional IED-related model.
ESI was concordant with non-invasive data in 13/15 different types of IED. The cESI model explained significant additional BOLD variance in regions concordant with video-EEG, structural MRI or, when available, intracranial EEG in 10/15 IED. The cESI model allowed better detection of the BOLD cluster, concordant with intracranial EEG in 4/7 IED, compared to the IED model. In 4 IED types, cESI-related BOLD signal changes were diffuse with a pattern suggestive of contamination of the source signal by artefacts, notably incompletely corrected motion and pulse artefact. In one IED type, there was no significant BOLD change with either model.
Continuous EEG source imaging can improve the modelling of BOLD changes related to interictal epileptic activity and this may enhance the localisation of the irritative zone.
脑电图相关功能磁共振成像（EEG-fMRI）研究可以揭示与癫痫发作间期放电（IED）相关的血流动力学变化。需要改进方法学以提高定位致痫区的敏感性和特异性。我们研究了与仅基于视觉识别 IED 的传统“事件相关”设计相比，估计的脑电图源活动是否改善了 EEG-fMRI 数据中 BOLD 变化的模型。
10 例药物难治性局灶性癫痫患者接受 EEG-fMRI 检查。对 fMRI 平均 IED 进行脑电图源成像（ESI），以确定刺激性区域。整个记录中该估计 IED 源的连续活动（cESI）用于 fMRI 分析（cESI 模型）。比较 cESI 解释的 BOLD 信号变化图与传统 IED 相关模型的结果。
ESI 在 13/15 种不同类型的 IED 中与非侵入性数据一致。在 10/15 个 IED 中，cESI 模型在与视频脑电图、结构 MRI 一致的区域或在有颅内 EEG 的情况下，解释了显著额外的 BOLD 方差。与 IED 模型相比，cESI 模型在 4/7 个 IED 中允许更好地检测到与颅内 EEG 一致的 BOLD 簇。在 4 种 IED 类型中，cESI 相关的 BOLD 信号变化是弥漫性的，模式提示源信号受到伪影的污染，尤其是不完全校正的运动和脉冲伪影。在一种 IED 类型中，两种模型均无显著的 BOLD 变化。
连续脑电图源成像可以改善与癫痫发作间期活动相关的 BOLD 变化的建模，这可能增强刺激性区域的定位。
