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Abstract #3321

Highly Accelerated EPI Evaluated for fMRI

Liyong Chen1, 2, An T. Vu1, 2, Junqian Xu3, Kamil Ugurbil3, Essa S. Yacoub3, David Feinberg, 24

1Advanced MRI Technologies, LLC, Sebastopol, CA, United States; 2Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States; 3CMRR, University of Minnesota, Minneapolis, MN, United States; 4Advanced MRI Technologies, Sebastopol, CA, United States

Multiplexed EPI utilizes multiband (MB) rf pulses and simultaneous image refocusing (SIR) to reduce the sampling TR of fMRI experiments. Here we evaluate different combinations of MB and SIR for accelerations up to N=48 images per EPI echo train. We found that for high accelerations, N>=8, multiplexed EPI with SIR 2 gave improvement over accelerations with MB alone in terms of tSNR, BOLD CNR, and BOLD information content. TRs around 600 300 ms gave the best single trial classification accuracy, suggesting significant BOLD information exists at very high temporal frequencies and demonstrating the importance of highly accelerated EPI for fMRI.

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Keywords

accelerated acceleration accelerations accuracy acquisition acquisitions activated address advanced aliasing allows alone authors best better board bold bottom brain channel checker classification classified coil combination constant content contrast contribution controlled coverage decreased developments dropout duration enabled equal especially evaluate evaluated evaluation evaluations even excitation exists expect expected experiment fixated flickering frame frames frequencies future gave generally highly holding human implementation importance improvement institute largest leave lengthened limitations limited longer made measured movie multiplexed near needed particularly pattern peak performance power project pulses quality quantified ramp recent reduce refocusing regional repeat repeated resolution resting sampling scanned significantly simultaneous slice slices slightly stimulation studies subject subjects subsequent suggest susceptibility task technologies temporal terms threshold train trial trio type uncorrected utilizes visual watching whole worse