  Purpose: To develop and evaluate a cardiovascular magnetic resonance sequence
(MyoFold) for rapid myocardial tissue and movement characterization. Method:
MyoFold sequentially performs joint T1/T2 mapping and cine for one
left-ventricle slice within a breathing-holding of 12 heartbeats. MyoFold uses
balanced Steady-State-Free-Precession (bSSFP) with 2-fold acceleration for data
readout and adopts an electrocardiogram (ECG) to synchronize the cardiac cycle.
MyoFold first acquires six single-shot inversion-recovery images at the
diastole of the first six heartbeats. For joint T1/T2 mapping, T2 preparation
(T2-prep) adds different T2 weightings to the last three images. On the
remaining six heartbeats, segmented bSSFP is continuously performed for each
cardiac phase for cine. We build a neural network and trained it using the
numerical simulation of MyoFold for T1 and T2 calculations. MyoFold was
validated through phantom and in-vivo experiments and compared to MOLLI, SASHA,
T2-prep bSSFP, and convention cine. Results: MyoFold phantom T1 had a 10%
overestimation while MyoFold T2 had high accuracy. MyoFold in-vivo T1 had
comparable accuracy to that of SASHA and precision to that of MOLLI. MyoFold
had good agreement with T2-prep bSSFP in myocardium T2 measurement. There was
no difference in the myocardium thickness measurement between the MyoFold cine
and convention cine. Conclusion: MyoFold can simultaneously quantify myocardial
tissue and movement, with accuracy and precision comparable to dedicated
sequences, saving three-fold scan time.
