Holocene Sampling: Where CAIPIRINHA meets T-Hex

Motivation: For Multiband and 3D EPI (and spirals), k-space sampling patterns used to date, were either optimized heuristically (blipped-CAIPIRINHA) or only available for a discrete subset of imaging parameters (T-Hex). Goal(s): To find the optimum sampling pattern for arbitrary imaging parameters. Approach: We propose the packing density of the k-space grid in the phase-encoding plane as a metric to assess the quality of a sampling pattern, since it minimizes the noise amplification for spherical objects. Furthermore, we choose L’s and Δ’s (blipped-CAIPIRINHA nomenclature) as real-valued numbers. Results: The novel sampling patterns achieve more homogeneous k-space coverage (up to 30% higher packing density) than blipped-CAIPIRINHA. Impact: The proposed method generates k-space sampling patterns that have potential to maximize the SNR yield per unit time in Multiband and 3D imaging by providing the most homogeneous k-space sampling for an arbitrary given set of imaging parameters.