Citation
Ramos Llordén, Gabriel and Vegas Sánchez-Ferrero, Gonzalo and Björk, Marcus and Vanhevel, Floris and Parizel, Paul M. and San José Estépar, Raúl and Dekker, Arnold J. den and Sijbers, Jan
(2018).
NOVIFAST: A Fast Algorithm for Accurate and Precise VFA MRI T1 Mapping.
"IEEE transactions on medical imaging", v. 37
(n. 11);
pp. 2414-2427.
ISSN 0278-0062.
https://doi.org/10.1109/TMI.2018.2833288.
Abstract
In quantitative magnetic resonance T1 mapping, the variable flip angle (VFA) steady state spoiled gradient recalled echo (SPGR) imaging technique is popular as it provides a series of high resolution T1 weighted images in a clinically feasible time. Fast, linear methods that estimate T1 maps from these weighted images have been proposed, such as DESPOT1 and iterative re-weighted linear least squares. More accurate, non-linear least squares (NLLS) estimators are in play, but these are generally much slower and require careful initialization. In this paper, we present NOVIFAST, a novel NLLS-based algorithm specifically tailored to VFA SPGR T1 mapping. By exploiting the particular structure of the SPGR model, a computationally efficient, yet accurate and precise T1 map estimator is derived. Simulation and in vivo human brain experiments demonstrate a twenty-fold speed gain of NOVIFAST compared with conventional gradient-based NLLS estimators while maintaining a high precision and accuracy. Moreover, NOVIFAST is eight times faster than the efficient implementations of the variable projection (VARPRO) method. Furthermore, NOVIFAST is shown to be robust against initialization.
