3D Radial GRE-EPI with Up to 8-Fold Acceleration for Functional Imaging at 9.4T

Introduction: Accelerating the acquisition of individual time frames is beneficial in fMRI since it increases statistical power and allows the separation of physiological noise components from the time series. An effective means to achieve this speed is to combine EPI with parallel imaging techniques. This combination offers the additional advantage of reduced distortion artifacts and T2 -related blurring in the phase-encoding direction of the EPI sequence. Depending on the coil setup, the move from 2D to 3D EPI can allow higher parallel imaging acceleration factors, since acceleration can now be performed in both phase-encoding directions. In order to allow even higher acceleration factors by exploiting coil sensitivity variations in all three dimensions, it is necessary to move to a non-Cartesian trajectory. To this end, a 3D EPI sequence was developed that combines an in-plane radial with a through-plane EPI readout. We present first results with up to 8-fold radial undersampling from finger tapping experiments at 9.4 T.