Towards accurate MRF T₂ in structured material at 0.55T using MT-suppressed excitations

To develop a 0.55 T FISP-MRF approach that provides more accurate T₂ maps in structured materials (e.g. white matter).

Non-selective low-bandwidth excitation strategies that reduce on-resonance MT effects were implemented. Dictionaries were simulated using a conventional single pool model. Estimated MRF T₂ maps using the non-selective approach with 2 pulse durations were compared against MRF T₂ maps using the conventional slab-selective approach, and against conventional but slow reference measurements.

The proposed approach substantially reduces T₂ underestimation in white matter from ∼40 % to <10 % without compromising precision.

The use of non-selective low-bandwidth excitations substantially reduces MT effects in 0.55T FISP-MRF, enabling use of a single pool model. This is particularly important for MRF at low field strengths and in structured materials such as white matter.