Free-breathing High-resolution 3D Whole-heart Adiabatic T1ρ Mapping at 0.55T

Motivation: Cardiac T1ρ mapping is promising for non-contrast myocardial scar assessment. However, there is scarce experience with T1ρ mapping at low-field. In a recent study, T1ρ produced by continuous wave spin-lock (SL) pulses demonstrated limited T1ρ dispersion at low-field. Goal(s): To devise an efficient 3D free-breathing high-resolution T1ρ mapping sequence based on adiabatic SL pulses at 0.55T with improved dispersion. Approach: The proposed sequence acquires four motion-corrected 3D volumes using saturation and adiabatic SL preparation pulses for T1ρ mapping. Results: The proposed 3D T1ρ sequence shows excellent agreement with reference sequence in phantom and provides comparable T1ρ results with a 2D sequence in-vivo. Impact: The proposed 3D T1ρ mapping sequence demonstrates the feasibility of non-invasive myocardial tissue characterization at 0.55T with 2mm isotropic-resolution in an efficient free-breathing scan of 7 mins. Both phantom and in-vivo 3D T1ρ measurements showed excellent agreements with reference sequences.