The utility of synchronization, PCA and filtering for removing MRI artefacts from simultaneous EEG recordings
Halder P, Brandeis D, Boesiger P, Mandelkow H
University of Zurich
The removal of MRI gradient artifacts from simultaneous EEG recordings is facilitated most effectively by eliminating drift between the MR scanner time base and the EEG clock. Precisely synchronized EEG-MRI recordings can be achieved by the use of a commercially available phase-locking device. We use simulations as well as EEG-MRI data recorded in a water phantom to assess the effectiveness of synchronized recordings in comparison to and in combination with other artefact reduction methods. Such post-processing methods like sampling time correction (STC) and principal component analysis (PCA) are seen to yield advantages mostly at frequencies above 80Hz but not in the crucial EEG range below 50Hz.