Lemieux Louis, Salek-Haddadi Afraim, Lund Torben E, Laufs Helmut, Carmichael David
Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College of London, Queen Square, WC1N 3BG London, UK.
Magn Reson Imaging. 2007 Jul;25(6):894-901. doi: 10.1016/j.mri.2007.03.009. Epub 2007 May 8.
EEG-correlated fMRI can provide localisation information on the generators of epileptiform discharges in patients with focal epilepsy. To increase the technique's clinical potential, it is important to consider ways of optimising the yield of each experiment while minimizing the risk of false-positive activation. Head motion can lead to severe image degradation and result in false-positive activation and is usually worse in patients than in healthy subjects. We performed general linear model fMRI data analysis on simultaneous EEG-fMRI data acquired in 34 cases with focal epilepsy. Signal changes associated with large inter-scan motion events (head jerks) were modelled using modified design matrices that include 'scan nulling' regressors. We evaluated the efficacy of this approach by mapping the proportion of the brain for which F-tests across the additional regressors were significant. In 95% of cases, there was a significant effect of motion in 50% of the brain or greater; for the scan nulling effect, the proportion was 36%; this effect was predominantly in the neocortex. We conclude that careful consideration of the motion-related effects in fMRI studies of patients with epilepsy is essential and that the proposed approach can be effective.
脑电图相关功能磁共振成像（EEG-correlated fMRI）可为局灶性癫痫患者癫痫样放电的起源提供定位信息。为提高该技术的临床应用潜力，重要的是要考虑优化每个实验的产出，同时将假阳性激活的风险降至最低。头部运动可导致严重的图像退化，并导致假阳性激活，而且在患者中通常比健康受试者更严重。我们对34例局灶性癫痫患者同步采集的脑电图-功能磁共振成像数据进行了一般线性模型功能磁共振成像数据分析。与大的扫描间运动事件（头部抽搐）相关的信号变化使用包含“扫描归零”回归变量的修改设计矩阵进行建模。我们通过绘制额外回归变量的F检验显著的脑区比例来评估该方法的有效性。在95%的病例中，50%或更大比例的脑区存在显著的运动效应；对于扫描归零效应，这一比例为36%；这种效应主要出现在新皮层。我们得出结论，在癫痫患者的功能磁共振成像研究中，仔细考虑与运动相关的效应至关重要，并且所提出的方法可能是有效的。
