Shells with Integrated RadiaL and Spiral (SWIRLS): An Improved Shells K-Space Trajectory

Yunhong Shu¹, Matt A. Bernstein¹

An improved method to sample k-space on a spherical surface is described. The novel trajectory, named shells with integrated radial and spiral (SWIRLS), eliminates the need for two helical spiral interleaves that cover the polar icecap region in the original shells trajectory. Phantom and volunteer experiments demonstrate the feasibility of the SWIRLS method. It has improved temporal efficiency compared to the shells trajectory, while overcoming the problems with phase discontinuity.