David A. Feinberg1,2, Steen Moeller3, Stephen Smith4, Edward Auerbach3, Kamil Ugurbil3, Essa Yacoub3
1Advanced MRI Technologies, Sebastopol, CA, USA; 2University of California, Berkeley & San Francisco, CA, USA; 3Center for Magnetic Resonance Research, University of Minnesota; 4FMRIB, Oxford University
A multiplexed-EPI (M-EPI) pulse sequence is presented that combines temporal multiplexing (m) utilizing simultaneous echo refocused (SIR) EPI and spatial multiplexing (n) with multibanded RF pulses (MB) to achieve m x n images in an EPI echo train. This resulted in significant increases in temporal resolution for whole brain fMRI evaluated at 0.8s and 0.4s TR in resting state and in substantial reductions in scan time 8.5m in HARDI neuronal fibertracks using 256 b-values. Multiplexed EPI can be used to acquire higher spatial resolutions, increase diffusion encoding, or to investigate temporal dynamics of the fMRI response.