Quadrature Slice-Encoding for Reduced Scan Time

Haisam Islam¹, Gary Glover²

We propose a new fMRI method for doubling the temporal resolution by simultaneously exciting pairs of adjacent slices in quadrature, and reconstructing them based on their phase distributions. The phase distributions are collected during a calibration scan, in which slices are individually excited with the same phase as in the quadrature excitation. The results show that the method is accurate in uniform brain regions, but fails in regions near large magnetic susceptibilities due to off-resonance and greater signal dropout. The effects of slice thickness, echo time, and number of simultaneously excited slices on reconstruction accuracy still need to be investigated.