Gradient noise cancelling for simultaneous EEG-fMRI recording
Constable R, Negishi M
Yale University, School of Medicine, Yale University, School of Medicine
Artifacts induced in the EEG during simultaneous EEG-fMRI acquisition are commonly removed by average waveform subtraction methods. However, these methods require EEG sampling timing correction, which is not suited for online artifact removal. We implemented a noise cancellation method utilizing dummy leads placed close to EEG electrodes. Since signals from the electrodes and the dummy leads are sampled at the same time, timing correction is unnecessary. With bipolar wiring and RF artifact-free recording, the artifact recorded from a phantom in a 3T scanner was 290 and 3.3 microvolts RMS before and after noise removal, demonstrating the effectiveness of the method.