Conventional 2D-EPI or Segmented 3D-EPI? A Temporal SNR Study at 3 and 7 Tesla

Abstract

This work studies the temporal SNR characteristics of conventional 2D-EPI and segmented 3D-EPI acquisitions under realistic conditions for standard and advanced applications. Therefore, different whole-brain protocols optimized for BOLD fMRI at normal and high spatial resolutions are prepared. Time series data are acquired at 3 and 7 Tesla. As expected, segmented 3D-EPI achieves higher tSNR than 2D-EPI at high spatial resolutions (thermal noise dominated regime). Beyond that, however, a general signal sensitivity advantage due to higher imaging acceleration capabilities (larger data rate, hence increased robustness of fMRI data) renders 3D-EPI useful even at typical, rather coarse resolutions.