Increasing temporal resolution in hybrid 3D EPI fMRI studies using unfold

In this work, we apply the UNFOLD technique to a hybrid 3D-EPI sequence in order to accelerate image acquisition for fMRI studies. UNFOLD is used in the 3D slice encoding direction which directly doubles the temporal resolution. Combining UNFOLD with Partial Fourier acqusition further reduces the acquisition time for a whole brain volume from 2.4 seconds to 1 seconds. The sequence was tested on healthy volunteers who were exposed to an audio-visual stimulus paradigm involving the solution of arithmetic problems. The temporal decoding of neural activity using the BOLD contrast mechanism improved significantly at the cost of a slight loss in SNR.