Acceleration of multi-echo high resolution brain imaging using variable-density sampling and patch-based regularization framework

Motivation: Long acquisition times facilitate the acquisition of high resolution multiparametric maps at 7T, however long scan times can lead to motion artefacts even with accelerated k-space sampling. Goal(s): Our goal is to reduce acquisition time and reduce motion artefacts using variable-density sampling. Approach: We use the variable-density-cartesian-trajectory (VD-CASPR) to retrospectively undersample the k-space of fully-sampled multi-echo GRE data in spiral-like interleaves for acceleration factors 6, 8 and 10. HDPROST regularisation framework is used to reduce motion artefacts taking advantage of the multiple echoes by patch-based denoising. Results: HDPROST enables greater acceleration potential taking avantage of the information redundancy and incoherent aliasing across echoes. Impact: This work demonstrates a reconstruction technique that may allow for faster high-resolution quantitative mapping which may be beneficial for a range of neurological applications, especially in the identification and characterization of small scale brain architecture and its alteration in pathology.