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

Area of Science:

• Cardiovascular magnetic resonance imaging
• Medical imaging techniques
• Myocardial tissue characterization

Background:

• Quantitative cardiac MRI, particularly T1 mapping, is crucial for assessing myocardial tissue.
• Conventional modified Look-Locker inversion recovery sequences have limitations in acquisition speed.

Purpose of the Study:

• To demonstrate the value of a radial variant of the conventional modified Look-Locker inversion recovery sequence (raMOLLI).
• To evaluate the raMOLLI sequence for ultrafast acquisition of myocardial T1 maps.

Main Methods:

• Utilized a radial acquisition scheme (raMOLLI) with radial echo trains.
• Employed view sharing and compressed sensing for image reconstruction.
• Applied dictionary fitting to estimate T1 values from the T1 relaxation recovery curve.
• Validated the sequence on phantoms, healthy subjects, and a patient with dilated cardiomyopathy.

Main Results:

• raMOLLI significantly decreased myocardial T1 map acquisition time to five heartbeats.
• Achieved higher accuracy and comparable precision in T1 estimation versus conventional sequences.
• The FLASH readout showed better robustness to B0 inhomogeneities than TrueFISP, making it preferable for in vivo use.

Conclusions:

• The raMOLLI sequence is a strong candidate for ultrafast myocardial T1 map acquisition.
• This advancement facilitates more efficient cardiac MRI examinations.