Analysis of "Scanner Ferquency" Noise in Fmri Timeseries

MRI system noise often appears in the fMRI timeseries in phantom and human subjects experiments. The predominant characteristic of this MRI system noise is high amplitude at one or a few specific temporal frequencies. These frequencies are immediately found by FFT analysis, but they have also been identified in ICA methods. This study indicates that these frequencies should be considered in the design of experimental paradigms and temporal digital filters.