000			02768 am a22002893u 4500
042			_adc
100	1	0	_aWest, Daniel J. _eauthor _91894
700	1	0	_aCruz, Gastao _eauthor _91895
700	1	0	_aTeixeira, Rui P. A. G. _eauthor _91896
700	1	0	_aSchneider, Torben _eauthor _91897
700	1	0	_aTournier, Jacques-Donald _eauthor _91898
700	1	0	_aHajnal, Joseph V. _eauthor
700	1	0	_aPrieto, Claudia _eauthor _91900
700	1	0	_aMalik, Shaihan J. _eauthor _91901
245	0	0	_aAn MR fingerprinting approach for quantitative inhomogeneous magnetization transfer imaging
260			_c2022-01-01.
500			_a/pmc/articles/PMC7614010/
500			_a/pubmed/34418151
520			_aPURPOSE: Magnetization transfer (MT) and inhomogeneous MT (ihMT) contrasts are used in MRI to provide information about macromolecular tissue content. In particular, MT is sensitive to macromolecules, and ihMT appears to be specific to myelinated tissue. This study proposes a technique to characterize MT and ihMT properties from a single acquisition, producing both semiquantitative contrast ratios and quantitative parameter maps. THEORY AND METHODS: Building on previous work that uses multiband RF pulses to efficiently generate ihMT contrast, we propose a cyclic steady-state approach that cycles between multiband and single-band pulses to boost the achieved contrast. Resultant time-variable signals are reminiscent of an MR fingerprinting acquisition, except that the signal fluctuations are entirely mediated by MT effects. A dictionary-based low-rank inversion method is used to reconstruct the resulting images and to produce both semiquantitative MT ratio and ihMT ratio maps, as well as quantitative parameter estimates corresponding to an ihMT tissue model. RESULTS: Phantom and in vivo brain data acquired at 1.5 Tesla demonstrate the expected contrast trends, with ihMT ratio maps showing contrast more specific to white matter, as has been reported by others. Quantitative estimation of semisolid fraction and dipolar T(1) was also possible and yielded measurements consistent with literature values in the brain. CONCLUSION: By cycling between multiband and single-band pulses, an entirely MT-mediated fingerprinting method was demonstrated. This proof-of-concept approach can be used to generate semiquantitative maps and quantitatively estimate some macromolecular-specific tissue parameters.
540			_a
540			_ahttps://creativecommons.org/licenses/by/4.0/This work is licensed under a CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) International license.
546			_aen
690			_aArticle
655	7		_aText _2local
786	0		_nMagn Reson Med
856	4	1	_uhttp://dx.doi.org/10.1002/mrm.28984 _zConnect to this object online.
999			_c1792 _d1792