An x,y phase correction method to eliminate image ghosts in single and multi shot EPI
GE Healthcare Technologies
Single and multi shot EPI recon is very sensitive to inconsistencies, i.e. a phase difference F(x, y) between k space lines acquired during alternate read gradient polarity or during different shots. F(x, y) is caused by position dependent eddy currents, anisotropy of the gradient system and field inhomogeneity, and is a function of the readout (x) and phase encoding (y) directions. In this abstract, we propose a simple pre scan and a close form algorithm to calculate F(x, y) and correct the image for any arbitrary number of shots. Experimental data show that this technique robustly eliminates EPI artifacts below detection levels in all imaging directions, even in systems with suboptimal calibrations.