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Improved MR fingerprinting for relaxation measurement in the presence of semisolid magnetization transfer
Author(s) -
Meng Yuguang,
Cheung Jesse,
Sun Phillip Zhe
Publication year - 2020
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.28159
Subject(s) - magnetization transfer , nuclear magnetic resonance , relaxation (psychology) , spin echo , chemistry , white matter , materials science , physics , magnetic resonance imaging , biology , medicine , neuroscience , radiology
Purpose To characterize and minimize the magnetization transfer (MT) effect in MR fingerprinting (MRF) relaxation measurements with a 2‐pool (2P) MT model of multiple tissue types. Theory and Methods Semisolid MT effect in MRF was modeled using 2P Bloch‐McConnell equations. The combinations of MT parameters of multiple tissues (white [WM] and gray matter [GM]) were used to build the MRF dictionary. Both 1‐pool (1P) and 2P models were simulated to characterize the dependence on MT. Relaxations measured using MRF with spin‐echo saturation‐recovery (SR) or inversion‐recovery preparations were compared with conventional SR‐prepared T 1 and multiple spin‐echo T 2 measurements. The simulations results were validated with phantoms and brain tissue samples. Results The MRF signal was different from the 1P and 2P models. 1P MRF produced significantly ( P < .05) underestimated T 1 in WM (20‐30%) and GM (7‐10%), while 2P MRF measured consistent T 1 and T 2 in both WM and GM with conventional measurements (pairwise test P > .1; correlated P < .05). Simulations showed that SR‐prepared MRF measuring T 1 had much less errors against the variation of the macromolecular fraction. Compared with inversion‐recovery preparation, SR‐prepared MRF produced higher relaxation correlations (R > 0.9) with conventional measurements in both WM and GM across samples, suggesting that SR‐prepared MRF was less sensitive to the compositive effect of multiple MT parameters variations. Conclusions 2P MRF using a combination of MT parameters for multiple tissue types can measure consistent relaxations with conventional methods. With the 2P models, SR‐prepared MRF would provide an option for robust relaxation measurement under heterogeneous MT.