Free-breathing, non-ECG, simultaneous myocardial T-1, T-2, T-2, and fat-fraction mapping with motion-resolved cardiovascular MR multitasking

Purpose To develop a free-breathing, non-electrocardiogram technique for simultaneous myocardial T-1, T-2, T-2*, and fat-fraction (FF) mapping in a single scan. Methods The MR Multitasking framework is adapted to quantify T-1, T-2, T-2*, and FF simultaneously. A variable TR scheme is developed to preserve temporal resolution and imaging efficiency. The underlying high-dimensional image is modeled as a low-rank tensor, which allows accelerated acquisition and efficient reconstruction. The accuracy and/or repeatability of the technique were evaluated on static and motion phantoms, 12 healthy volunteers, and 3 patients by comparing to the reference techniques. Results In static and motion phantoms, T-1/T-2/T-2*/FF measurements showed substantial consistency (R > 0.98) and excellent agreement (intraclass correlation coefficient > 0.93) with reference measurements. In human subjects, the proposed technique yielded repeatable T-1, T-2, T-2*, and FF measurements that agreed with those from references. Conclusions The proposed free-breathing, non-electrocardiogram, motion-resolved Multitasking technique allows simultaneous quantification of myocardial T-1, T-2, T-2*, and FF in a single 2.5-min scan.