Full and hybrid 2-dimensional navigator echo correction: new techniques to suppress respiratory-induced physiological noise in echo-planar functional MRI
Barry R, Menon R
Robarts Research Institute, University of Western Ontario
Functional MRI acquired using multi-shot EPI is particularly sensitive to spatially and temporally varying frequency offsets induced by respiration. As global and 1D navigator echo correction techniques have been shown to both amplify and suppress respiratory-induced physiological noise in different regions of an image, the use of full 2D navigator echo correction is investigated. Using a priori information of the slow spatial variations of this induced frequency offset map, the full 2D correction approach is modified to design a computationally efficient hybrid 2D navigator echo correction technique for 2-shot EPI with noise suppression performance comparable to its full 2D counterpart.