Time-dependent Diffusion in the Human Heart In Vivo

Conventional spin-echo based cardiac diffusion tensor imaging (DTI) has a relatively limited range of encoding frequencies, and hence limited sensitivity to diffusion at different length scales. Here, we explored the feasibility of applying a broader range of frequencies to evaluate the effects of time-dependent diffusion. We employed diffusion encoding waveforms with up to 4th order motion-compensation in a cohort of healthy volunteers, and report trends of decreasing MD and FA with increasing encoding frequencies. The availability of higher frequencies enhances the sensitivity of DTI to shorter length scales, and may be more greatly weighted towards diffusion properties of sub-cellular structures.