Myocardial T1 mapping using an instantaneous signal loss simulation modeling and a Bayesian estimation method: A robust T1 extraction method free of tuning parameters.

The Instantaneous Signal Loss Simulation (InSiL) model is a promising alternative to the classical mono-exponential fitting of the Modified Look-Locker Inversion-recovery (MOLLI) sequence in cardiac T mapping applications, which achieves better accuracy and is less sensitive to heart rate (HR) variations. Classical non-linear least squares (NLLS) estimation methods require some parameters of the model to be fixed a priori in order to give reliable T estimations and avoid outliers. This introduces further bias in the estimation, reducing the advantages provided by the InSiL model.

Temporal registration: a new approach to manage the incomplete recovery of the longitudinal magnetization in the Modified Look-Locker Inversion Recovery sequence (MOLLI) for T1 mapping of the heart.

Purpose: To correct with post-processing effects of incomplete recovery of the longitudinal magnetization before a new inversion pulse in the Modified Look-Locker Inversion recovery sequence (MOLLI) sequence.

Theory And Methods: We model such effects as a temporal shift ([Formula: see text]) of the signal of the Look-Locker block following next inversion pulses. After using the following equation [Formula: see text], a temporal registration of [Formula: see text] is applied to the signal of the affected block to adjust the sampling time of the recovery signal and correct the underlying effect on quantitative T1.