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.