BOLD-fMRI Using a 3D Ultrafast Gradient-echo-based Sequence Using Quadratic-phase Encoding (RASE-II) in Comparison with 2D and 3D EPI

We recently introduced a novel ultrafast 3D gradient-echo-based imaging technique using spatio-temporal encoding (SPEN) or quadratic-phase encoding, which were dubbed RASE-I and -II (Rapid Acquisition with Sequential Excitation). RASE has less sensitivity to field inhomogeneities and susceptibility differences compared to conventional gradient-echo EPI (GE-EPI), sharing the advantages of 3D imaging such as high signal-to-noise ratio and high spatial resolution. In this study, we present promising results of RASE-II fMRI, i.e., better t-scores, tSNR than conventional 2D and 3D GE-EPI, on a 9.4-T animal scanner.