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A robust methodology for in vivo T 1 mapping
Author(s) -
Barral Joëlle K.,
Gudmundson Erik,
Stikov Nikola,
EtezadiAmoli Maryam,
Stoica Petre,
Nishimura Dwight G.
Publication year - 2010
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22497
Subject(s) - initialization , imaging phantom , algorithm , computer science , dimension (graph theory) , hyperparameter optimization , minification , range (aeronautics) , nonlinear system , estimation theory , mathematics , mathematical optimization , artificial intelligence , physics , optics , materials science , quantum mechanics , support vector machine , pure mathematics , composite material , programming language
In this article, a robust methodology for in vivo T 1 mapping is presented. The approach combines a gold standard scanning procedure with a novel fitting procedure. Fitting complex data to a five‐parameter model ensures accuracy and precision of the T 1 estimation. A reduced‐dimension nonlinear least squares method is proposed. This method turns the complicated multi‐parameter minimization into a straightforward one‐dimensional search. As the range of possible T 1 values is known, a global grid search can be used, ensuring that a global optimal solution is found. When only magnitude data are available, the algorithm is adapted to concurrently restore polarity. The performance of the new algorithm is demonstrated in simulations and phantom experiments. The new algorithm is as accurate and precise as the conventionally used Levenberg‐Marquardt algorithm but much faster. This gain in speed makes the use of the five‐parameter model viable. In addition, the new algorithm does not require initialization of the search parameters. Finally, the methodology is applied in vivo to conventional brain imaging and to skin imaging. T 1 values are estimated for white matter and gray matter at 1.5 T and for dermis, hypodermis, and muscle at 1.5 T, 3 T, and 7 T. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.