An improved real-time navigator gating algorithm for reducing motion effects in coronary magnetic resonance angiography.

The phase ordering with automatic window selection (PAWS) algorithm for respiratory gating in magnetic resonance imaging is improved by further smoothing motion distribution in k-space. This is achieved by requiring that the displacement discontinuities in k-space and the range of displacement during the acquisition of the center 30% region of k-space are limited to a fraction (1/3 in this study) of the gating window. Simulation results and in vivo imaging experiments suggest that these modifications reduce the amount of artifacts at a reasonable cost of additional scan time as compared to the original PAWS algorithm.