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Instantaneous signal loss simulation (InSiL): An improved algorithm for myocardial T 1 mapping using the MOLLI sequence
Author(s) -
Shao Jiaxin,
Nguyen KimLien,
Natsuaki Yutaka,
Spottiswoode Bruce,
Hu Peng
Publication year - 2015
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.24599
Subject(s) - imaging phantom , algorithm , signal (programming language) , mathematics , computer science , nuclear medicine , medicine , programming language
Purpose To propose a T 1 mapping algorithm for the modified Look‐Locker inversion‐recovery (MOLLI) sequence that can improve T 1 estimation accuracy. Materials and Methods The modified T 1 mapping algorithm (InSiL) is based on the simulation of MOLLI signal evolution and simulates the longitudinal magnetization signal perturbation by each single‐shot image acquisition in MOLLI as an instantaneous signal loss. InSiL was evaluated against original MOLLI using Bloch simulations, phantom studies, and in 15 healthy volunteers at 1.5T. Results In phantom studies, the maximum absolute error by InSiL is less than 2%, while that by MOLLI is more than 20% for T 1 values from 221 msec to 1539 msec. The benefit of InSiL is greatest at heart rate (HR) >80 bpm and T 1 >1000 msec, and InSiL reduced MOLLI T 1 error from 14.9 ± 4.5% to 0.4 ± 0.3%. Average InSiL‐derived native myocardial T 1 values at 1.5T in healthy volunteers were significantly higher than MOLLI‐derived values by 236.9 ± 11.7 msec (1160.3 ± 25.1 msec vs. 923.4 ± 22.3 msec, P < 0.001) at an average HR of 65.1 ± 14.7 bpm. Conclusion The proposed InSiL approach yields better T 1 mapping accuracy than MOLLI, and is less sensitive to HR variation in tissues with longer T 1 values. J. Magn. Reson. Imaging 2015;41:721–729. © 2014 Wiley Periodicals, Inc.