Ghent University, Department of Electronics and Information Systems, MEDISIP-IBBT-IbiTech, De Pintelaan 185, B-9000 Ghent, Belgium.
Clin Neurophysiol. 2010 May;121(5):672-85. doi: 10.1016/j.clinph.2009.12.032. Epub 2010 Jan 25.
This work investigates the influence of the static magnetic field of the MR-scanner on ERPs extracted from simultaneous EEG-fMRI recordings. The quality of the ERPs after BallistoCardioGraphic (BCG) artifact removal, as well as the reproducibility of the waveforms in different environments is investigated.
We consider a Detection, a Go-Nogo and a Motor task, eliciting peaks that differ in amplitude, latency and scalp topography, repeated in two situations: outside the scanner room (0T) and inside the MR-scanner but without gradients (3T). The BCG artifact is removed by means of three techniques: the Average Artifact Subtraction (AAS) method, the Optimal Basis Set (OBS) method and the Canonical Correlation Analysis (CCA) approach.
The performance of the three methods depends on the amount of averaged trials. Moreover, differences are found on both amplitude and latency of ERP components recorded in two environments (0T vs 3T).
We showed that, while ERPs can be extracted from simultaneous EEG-fMRI data at 3T, the static magnetic field might affect the physiological processes under investigation.
The reproducibility of the ERPs in different recording environments (0T vs 3T) is a relevant issue that deserves further investigation to clarify the equivalence of cognitive processes in both behavioral and imaging studies.
本研究旨在调查磁共振扫描仪的静态磁场对同时进行的脑电图-功能磁共振成像（EEG-fMRI）记录中提取的事件相关电位（ERP）的影响。研究了在 BallistoCardioGraphic（BCG）伪影去除后 ERP 的质量，以及在不同环境下波形的可重复性。
我们考虑了一个检测、一个 Go-Nogo 和一个运动任务，引出了在幅度、潜伏期和头皮地形图上不同的峰值，在两种情况下重复进行：在扫描仪室外（0T）和在没有梯度的磁共振扫描仪内（3T）。通过三种技术去除 BCG 伪影：平均伪影减法（AAS）方法、最优基集（OBS）方法和典型相关分析（CCA）方法。
三种方法的性能取决于平均试验次数。此外，在两种环境（0T 与 3T）记录的 ERP 成分的幅度和潜伏期上都存在差异。
我们表明，虽然可以从 3T 的同时 EEG-fMRI 数据中提取 ERP，但静态磁场可能会影响正在研究的生理过程。
在不同记录环境（0T 与 3T）中 ERP 的可重复性是一个值得进一步研究的重要问题，以澄清行为和成像研究中认知过程的等效性。
