Assessment of MRF for simultaneous T1 and T2 quantification and water-fat separation in the liver at 0.55T.

Abstract

The goal of this work was to assess the feasibility of performing MRF in the liver on a 0.55T scanner and to examine the feasibility of water-fat separation using rosette MRF at 0.55T. Spiral and rosette MRF sequences were implemented on a commercial 0.55T scanner. The accuracy of both sequences in T1 and T2 quantification was validated in the ISMRM/NIST system phantom. The efficacy of rosette MRF in water-fat separation was evaluated in simulations and water/oil phantoms. Both spiral and rosette MRF were performed in the liver of healthy subjects. In the ISMRM/NIST phantom, both spiral and rosette MRF achieved good agreement with reference values in T1 and T2 measurements. In addition, rosette MRF enables water-fat separation and can generate water- and fat- specific T1 maps, T2 maps, and proton density images from the same dataset for a spatial resolution of 1.56 × 1.56 × 5mm3 within the acquisition time of 15s. It is feasible to measure T1 and T2 simultaneously in the liver using MRF on a 0.55T system with lower performance gradients compared to state-of-the-art 1.5T and 3T systems within an acquisition time of 15s. In addition, rosette MRF enables water-fat separation along with T1 and T2 quantification with no time penalty.