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The cost of parallel imaging in functional MRI of the human brain.

Lütcke H, Merboldt KD, Frahm J

Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie, 37070 Göttingen, Germany. hluetck@gwdg.de

While the advantages of parallel acquisition techniques for echo-planar imaging (EPI) are well documented for studies affected by magnetic field inhomogeneities, this work focuses on the costs in functional MRI of brain regions without artifacts due to susceptibility effects. For a visual stimulation paradigm and relative to conventional EPI (2.9 T; TR/TE=2000/36 ms), the use of parallel acquisition at a reduction factor of 2 decreased the mean number of activated voxels by 21% at 2 x 2 x 2-mm(3) resolution (n=6) and by 15% at 3 x 3 x 3-mm(3) resolution (n=6). The loss of sensitivity reflects both a decreased signal-to-noise ratio of the native images due to a lower number of contributing gradient echoes and a decreased BOLD MRI sensitivity due to the coverage of a smaller range of TEs.

Published 13 January 2006 in Magn Reson Imaging, 24(1): 1-5.
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