Fast, precise, and accurate myocardial T1 mapping using a radial MOLLI sequence with FLASH readout

PURPOSE

Quantitative cardiac MRI, and more particularly T₁ mapping, has become a most important modality to characterize myocardial tissue. In this work, the value of a radial variant of the conventional modified Look-Locker inversion recovery sequence (raMOLLI) is demonstrated.

METHODS

The raMOLLI acquisition scheme consisted of five radial echo trains of 80 spokes acquired using either a fast low-angle shot (FLASH) or a true fast imaging with steady-state-precession (TrueFISP) readout at different time points after a single magnetization inversion. View sharing combined with a compressed sensing algorithm allowed the reconstruction of 50 images along the T₁ relaxation recovery curve, to which a dictionary-fitting approach was applied to estimate T₁ . The sequence was validated on a nine-vial phantom, on 19 healthy subjects, and one patient suffering from dilated cardiomyopathy.

RESULTS

The raMOLLI sequence allowed a significant decrease of myocardial T₁ map acquisition time down to five heartbeats, while exhibiting a higher degree of accuracy and a comparable precision on T₁ value estimation than the conventional modified Look-Locker inversion recovery sequence. The FLASH readout demonstrated a better robustness to B₀ inhomogeneities than TrueFISP, and was therefore preferred for in vivo acquisitions.

CONCLUSIONS

This sequence represents a good candidate for ultrafast acquisition of myocardial T₁ maps. Magn Reson Med 79:1387-1398, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

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