Efficient High-Resolution Cardiac DTI with Spiral Keyhole Sampling (SPIK) and Joint Spatial-Angular Sparse Representation

Motivation: In cardiac diffusion MRI, spatial resolution is often limited by the available SNR and scan time. However, reducing voxel size enables precise microstructure characterisation. Goal(s): To develop and evaluate the feasibility of a new sampling/reconstruction scheme that takes advantage of similarities between diffusion-weighted images in (k,q) space in order to provide high spatial resolution with significantly reduced scan times. Approach: A new spiral-based sampling scheme is proposed and its benefits when combined with an efficient reconstruction is demonstrated through simulations. Results: Evaluations showed that the proposed technique provides high-quality diffusion parameter maps comparable to fully sampled reference data with RMSEs less than 4%. Impact: We introduce a novel sampling technique for accelerating high-resolution cardiac diffusion tensor imaging (cDTI). Harnessing the improved spatial resolution and scan time reduction has the potential to make significant contributions to practicability of more complex diffusion models in the heart.