Tensor-valued encoded diffusion MRI with spiral readout for whole-brain mapping of microscopic fractional anisotropy

Motivation: Improvement of the quantification of the microstructure in the human brain with tensor-valued encoded diffusion MRI. Goal(s): Obtain whole-brain macro- and microscopic diffusion tensor distribution metrics using spiral k-space trajectories at 7T. Approach: Two diffusion-weighted sequences realizing the QTI approach were designed with Pulseq. They were compared to each other and to an additionally acquired DTI sequence including a ROI analysis. Results: Accurate metric maps were obtained which are in accordance with the literature and DTI values. Impact: Combining a multiband spiral sequence with advanced diffusion weighting enables fast whole-brain mapping of microscopic fractional anisotropy in 11-12 minutes.