Improvement of Gradient-Reversal EPI Undistortion Method Using Local Pixel Adjustment
Liu X, Zhong J
University of Rochester
Echo planar imaging (EPI) suffers severe geometry and intensity distortions because of its inherently long acquisition window in the phase encoding direction. Gradient-reversal undistortion method can successfully correct both the geometry and intensity distortions induced by field inhomogeneity. The essence of this method is to find the corresponding points in forward and reverse phase-encoding gradient images. We propose an improved algorithm with local pixel adjustment to find corresponding points in EPI images. It is an effective and fast improvement of the original algorithm.