Cardiac Magnetic Resonance Fingerprinting for Simultaneous T1, T2, and Fat-Fraction Quantification at 0.55 T

Area of Science:

• Medical Imaging
• Cardiovascular MRI
• Quantitative MRI

Background:

• Cardiac magnetic resonance fingerprinting (cMRF) enables simultaneous quantitative myocardial tissue characterization.
• Previous cMRF studies have focused on 1.5T and 3T, with limited exploration at lower field strengths.
• Low-field MRI offers potential advantages in accessibility and cost.

Purpose of the Study:

• To adapt and validate a Dixon cMRF sequence for simultaneous T1, T2, and fat fraction (FF) quantification at 0.55T.
• To assess the feasibility and accuracy of the adapted cMRF technique in phantoms and healthy volunteers.
• To evaluate the performance of 0.55T cMRF compared to conventional mapping sequences.

Main Methods:

• Development of an adapted Dixon cMRF sequence using the Pulseq environment with radial tiny golden angle acquisition and bipolar readout.
• Reconstruction using low-rank inversion and high-dimensional patch-based regularization.
• Validation in standardized phantoms and 15 healthy volunteers, comparing results with spin-echo and proton density references, and conventional T1, T2, and FF mapping sequences.

Main Results:

• Excellent correlation (R² ≥ 0.97) between 0.55T cMRF and phantom references for T1, T2, and FF.
• Low intrasession and intersession variability for T1, T2, and FF measurements in phantoms and volunteers.
• Good in vivo map quality with mean myocardial values comparable to conventional methods, showing good agreement for T1 and FF, though T2 was underestimated.

Conclusions:

• The adapted Dixon cMRF technique is feasible for simultaneous T1, T2, and FF quantification at 0.55T.
• The method demonstrates good accuracy and reproducibility, supporting its potential for myocardial tissue characterization.
• Further studies in larger cohorts and patient populations are warranted to fully establish its clinical utility.