On the use of the "look-locker correction" for calculating T1 values from MOLLI

Background MOLLI [1] uses interleaved Look-Locker (LL) blocks for cardiac T1 mapping. Data is fit to the equation A-Bexp (-TI/T1*) to yield an “apparent” T1 (T1*), which is dependent on both the true T1 and imaging parameters. To estimate true T1, a “LL correction” T1est=(B/A-1) T1* [Eq. 1] has been proposed [1,2]. Although this correction can provide reasonable estimates of true T1, we are not aware of a rigorous justification for its use. The purpose of this work was to investigate the applicability of this correction for MOLLI.