MR fingerprinting for rapid quantification of myocardial T₁ , T₂ , and proton spin density

To introduce a two-dimensional MR fingerprinting (MRF) technique for quantification of T₁ , T₂ , and M₀ in myocardium.

An electrocardiograph-triggered MRF method is introduced for mapping myocardial T₁ , T₂ , and M₀ during a single breath-hold in as short as four heartbeats. The pulse sequence uses variable flip angles, repetition times, inversion recovery times, and T₂ 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.

T₁ and T₂ measurements from the proposed cardiac MRF sequence correlated well with standard spin echo measurements in the phantom study (R²  > 0.99). A Bland-Altman analysis revealed good agreement for myocardial T₁ measurements between MRF and MOLLI (bias 1 ms, 95% limits of agreement -72 to 72 ms) and T₂ measurements between MRF and T₂ -prepared balanced steady-state free precession (bias, -2.6 ms; 95% limits of agreement, -8.5 to 3.3 ms).

MRF can provide quantitative single slice T₁ , T₂ , and M₀ maps in the heart within a single breath-hold. Magn Reson Med 77:1446-1458, 2017. © 2016 International Society for Magnetic Resonance in Medicine.