MR Fingerprinting for Rapid Quantification of Myocardial T1, T2, and Proton Spin Density

Purpose: To introduce a two-dimensional MR fingerprinting (MRF) technique for quantification of T-1, T-2, and M0 in myocardium. Methods: An electrocardiograph-triggered MRF method is introduced for mapping myocardial T-1, T-2, and M-0 during a single breath-hold in as short as four heartbeats. The pulse sequence uses variable flip angles, repetition times, inversion recovery times, and T-2 preparation dephasing times. A dictionary of possible signal evolutions is simulated for each scan that incorporates the subject's unique variations in heart rate. Aspects of the sequence design were explored in simulations, and the accuracy and precision of cardiac MRF were assessed in a phantom study. In vivo imaging was performed at 3 Tesla in 11 volunteers to generate native parametric maps. Results: T-1 and T-2 measurements from the proposed cardiac MRF sequence correlated well with standard spin echo measurements in the phantom study (R-2 > 0.99). A Bland-Altman analysis revealed good agreement for myocardial T-1 measurements between MRF and MOLLI (bias 1 ms, 95% limits of agreement -72 to 72 ms) and T-2 measurements between MRF and T-2-prepared balanced steady-state free precession (bias, 2.6 ms; 95% limits of agreement, 8.5 to 3.3 ms). Conclusion: MRF can provide quantitative single slice T-1, T-2, and M-0 maps in the heart within a single breath-hold. (C) 2016 International Society for Magnetic Resonance in Medicine