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Inversion group (IG) fitting: A new T 1 mapping method for modified look‐locker inversion recovery (MOLLI) that allows arbitrary inversion groupings and rest periods (including no rest period)
Author(s) -
Sussman Marshall S.,
Yang Issac Y.,
Fok KaiHo,
Wintersperger Bernd J.
Publication year - 2016
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.25829
Subject(s) - inversion (geology) , rest (music) , algorithm , inverse transform sampling , mathematics , computer science , geology , physics , seismology , telecommunications , acoustics , surface wave , tectonics
Purpose The Modified Look‐Locker Inversion Recovery (MOLLI) technique is used for T 1 mapping in the heart. However, a drawback of this technique is that it requires lengthy rest periods in between inversion groupings to allow for complete magnetization recovery. In this work, a new MOLLI fitting algorithm (inversion group [IG] fitting) is presented that allows for arbitrary combinations of inversion groupings and rest periods (including no rest period). Theory and Methods Conventional MOLLI algorithms use a three parameter fitting model. In IG fitting, the number of parameters is two plus the number of inversion groupings. This increased number of parameters permits any inversion grouping/rest period combination. Validation was performed through simulation, phantom, and in vivo experiments. Results IG fitting provided T 1 values with less than 1% discrepancy across a range of inversion grouping/rest period combinations. By comparison, conventional three parameter fits exhibited up to 30% discrepancy for some combinations. The one drawback with IG fitting was a loss of precision—approximately 30% worse than the three parameter fits. Conclusion IG fitting permits arbitrary inversion grouping/rest period combinations (including no rest period). The cost of the algorithm is a loss of precision relative to conventional three parameter fits. Magn Reson Med 75:2332–2340, 2016. © 2015 Wiley Periodicals, Inc.