Myocardial T1 mapping at 5T using multi-inversion recovery real-time spoiled GRE

Abstract

Objective: To develop an accurate myocardial T1 mapping technique at 5T using Look-Locker-based multiple inversion-recovery with the real-time spoiled gradient echo (GRE) acquisition. Approach: The proposed T1 mapping technique (mIR-rt) samples the recovery of inverted magnetization using the real-time GRE and the images captured during diastole are selected for T1 fitting. Multiple-inversion recoveries are employed to increase the sample size for accurate fitting. The T1 mapping method was validated using Bloch simulation, phantom studies, and in 16 healthy volunteers at 5T. Main results: In both simulation and phantom studies, the T1 values measured by mIR-rt closely approximate the reference T1 values, with errors less than 3%, while the conventional MOLLI sequence underestimates T1 values. The myocardial T1 values at 5T are 1553 +/- 52 ms, 1531 +/- 53 ms, and 1526 +/- 60 ms (mean +/- standard deviation) at the apex, middle, and base, respectively. The T1 values measured by MOLLI (1350 +/- 48 ms, 1349 +/- 47 ms, and 1354 +/- 45 ms at the apex, middle, and base) were significantly lower than those of mIR-rt with p<0.001 for all three layers. The mIR-rt sequence method used in our study provides high reproducibility, particularly in the middle slices, supporting its practical relevance for myocardial T1 mapping. Significance: The proposed method is feasible for myocardial T1 mapping at 5T and provides better accuracy than the conventional MOLLI sequence.