A new Approach Predicting Optimal Imaging Gradient Orientation for EPI
v. Mengershausen M, Speck O, Rick J
University Hospital Freiburg
Echo planar imaging (EPI) is commonly used for functional magnetic resonance imaging (fMRI). Its sensitivity to susceptibility gradients enables the measurement of the blood oxygen level dependent effect (BOLD). But this sensitivity also implies geometric distortions and signal loss due to field inhomogeneities not related to BOLD. In this work the signal loss, which is dependent on the orientation of the spatial encoding gradients, is predicted in order to prospectively select the optimal parameter setting for the acquisition. The signal loss is calculated by numerical prediction of signal loss, and is based on measured three dimensional B0 maps.