AUTHOR=Mao Xianglun , Lee Hsu-Lei , Hu Zhehao , Cao Tianle , Han Fei , Ma Sen , Serry Fardad M. , Fan Zhaoyang , Xie Yibin , Li Debiao , Christodoulou Anthony G. 

TITLE=Simultaneous Multi-Slice Cardiac MR Multitasking for Motion-Resolved, Non-ECG, Free-Breathing T1–T2 Mapping

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2022.833257

DOI=10.3389/fcvm.2022.833257

ISSN=2297-055X

ABSTRACT=This work is to simultaneously quantify T1/T2 across three slices of the left-ventricular myocardium without breath-holds or ECG monitoring, all within a 3-min scan. Radial simultaneous multi-slice (SMS) encoding, self-gating, and image reconstruction was incorporated into the cardiovascular MR (CMR) Multitasking framework to simultaneously image three short-axis slices. A T2prep-IR FLASH sequence with two flip angles was designed and implemented to allow B1+-robust T1 and T2 mapping. The proposed Multitasking-SMS method was validated in the ISMRM-NIST phantom and 10 healthy volunteers, comparing T1 and T2 measurements and scan-rescan repeatability against corresponding reference methods in one layer of phantom vials and in 16 AHA myocardial segments. In phantom, Multitasking-SMS T1/T2 measurements showed substantial correlation (R2>0.996) and excellent agreement (ICC≥0.999) with reference measurements. In healthy volunteers, Multitasking-SMS T1/T2 maps reported similar myocardial T1/T2 values (1215±91.0/41.5±6.3 ms) to the reference myocardial T1/T2 values (1239±67.5/42.7±4.1 ms), with P=0.347 and P=0.296, respectively. Bland-Altman analyses also demonstrated good in vivo repeatability in both Multitasking and references, with segment-wise coefficients of variation of 4.7% (Multitasking T1), 8.9% (Multitasking T2), 2.4% (MOLLI), 4.6% (T2-prep FLASH), respectively. In summary, Multitasking-SMS is feasible for free-breathing, non-ECG, myocardial T1/T2 quantification in 16 AHA segments over 3 short-axis slices in 3 mins. The method shows the great potential for reducing exam time for quantitative CMR without ECG or breath-holds.