Motion‐corrected model‐based reconstruction for 2D myocardial T1 mapping

Abstract

PurposeTo allow for T1 mapping of the myocardium within 2.3 s for a 2D slice utilizing cardiac motion‐corrected, model‐based image reconstruction.MethodsGolden radial data acquisition is continuously carried out for 2.3 s after an inversion pulse. In a first step, dynamic images are reconstructed which show both contrast changes due to T1 recovery and anatomical changes due to the heartbeat. An image registration algorithm with a signal model for T1 recovery is applied to estimate non‐rigid cardiac motion. In a second step, estimated motion fields are applied during an iterative model‐based T1 reconstruction. The approach was evaluated in numerical simulations, phantom experiments and in in‐vivo scans in healthy volunteers.ResultsThe accuracy of cardiac motion estimation was shown in numerical simulations with an average motion field error of 0.7 ± 0.6 mm for a motion amplitude of 5.1 mm. The accuracy of T1 estimation was demonstrated in phantom experiments, with no significant difference (p = 0.13) in T1 estimated by the proposed approach compared to an inversion‐recovery reference method. In vivo, the proposed approach yielded 1.3 × 1.3 mm T1 maps with no significant difference (p = 0.77) in T1 and SDs in comparison to a cardiac‐gated approach requiring 16 s scan time (i.e., seven times longer than the proposed approach). Cardiac motion correction improved the precision of T1 maps, shown by a 40% reduced SD.ConclusionWe have presented an approach that provides T1 maps of the myocardium in 2.3 s by utilizing both cardiac motion correction and model‐based T1 reconstruction.