1Institute of Neuroscience and Medicine - 4, Research Centre Juelich GmbH, Jlich, Germany; 2Department of Neurology, Faculty of Medicine, JARA, RWTH Aachen University, Aachen, Germany
A simple modification of a 3D-EPI sequence is proposed which renders additional time- and SAR-demanding fat suppression obsolete. Instead, using a rectangular excitation pulse yields robust fat suppression with minimal SAR if the pulse duration is selected carefully. This method, particularly useful for high field application, facilitates high-resolution functional imaging (fMRI) at temporal resolutions of two seconds or less. The basic concept and an expression for the optimal pulse duration (also valid for large flip angles) are introduced, validated in vivo at 3T and applied to finger tapping fMRI at 1.5mm isotropic resolution.