Colored Noise and Effective Resolution: Data considerations for non-uniform k-space sampling reconstructions
Newbould R, Bammer R, Liu C
Non-Cartesian acquisition schemes, such as PROPELLER and variable density spirals offer a number of distinct advantages over Cartesian methods. These trajectories are designed to repeatedly sample data near the origin of k-space. When sampled data is regridded, regions near the center of k-space have a greater SNR than those at the periphery. The result is colored noise in the final reconstructed image: a loss of SNR near contrast changes, which reduces the effective resolution of the image. The colored noise can be quite distracting when appraising an image. Here we propose a noise recoloring method, which only decreases SNR in frequencies which have artificially increased SNR above that of the acquisition.