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Abstract #1164

Length-Scale Dependent Effects of Noise Reduction in Phase and Magnitude FMRI Time-Series

Gisela E. Hagberg1, Marta Bianciardi2, Valentina Brainovich1, Antonino Maria Cassara3,4, Bruno Maraviglia3,4

1Santa Lucia Scientific Foundation, Rome, Italy; 2Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States; 3Dept. Physics, Sapienza University, Rome, Italy; 4Centro Studi e Ricerche "Enrico Fermi"

fMRI analyses are primarily based on the magnitude information in gradient-echo echo-planar images (GE-EPI) but a growing number of studies also included the phase information. An issue relates to physiologic large-scale phase effects that are more prominent in phase than magnitude data. In the present work we explored the phase stability at different length scales at 3T and found that improvements in temporal stability could be achieved by alternative noise-reduction methods that take into account the differential origin of noise effects in phase and magnitude data.