Lars Kasper1,2, S. Johanna Vannesj1, Maximimilian Hberlin1, Christoph Barmet1, Klaas Enno Stephan2,3, Klaas Paul Prssmann1
1University and ETH Zurich, Institute for Biomedical Engineering, Zurich, Switzerland; 2Institute for Empirical Research in Economics, University of Zurich, Laboratory for Social and Neural Systems Research, Zurich, Switzerland; 3 Institute of Neurology, University College London, Wellcome Trust Centre for Neuroimaging, London, United Kingdom
Smoothing MR-images is a common preprocessing step in areas like functional MRI to improve signal as well as noise characteristics of the images and facilitate inter-subject comparison. We present how an EPI-acquisition scheme (1.5 mm resolution) whose density is specifically tailored to match an image smoothing kernel improves the SNR of the finally smoothed images. Furthermore, this shows the opportunity to assign differing spatial properties to signal and noise contributions within an MR image. Because these non-uniform trajectories differ from common MR gradient demands, we relied on actually measured trajectories for our reconstructions, using an NMR field monitoring setup.