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30‐Second bound and pore water concentration mapping of cortical bone using 2D UTE with optimized half‐pulses
Author(s) -
Manhard Mary Kate,
Harkins Kevin D.,
Gochberg Daniel F.,
Nyman Jeffry S.,
Does Mark D.
Publication year - 2017
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.26605
Subject(s) - cortical bone , bound water , pulse (music) , nuclear magnetic resonance , materials science , magnetic resonance imaging , tibia , fracture (geology) , pulse sequence , chemistry , biomedical engineering , anatomy , optics , physics , composite material , radiology , medicine , molecule , organic chemistry , detector
Purpose MRI of cortical bone has the potential to offer new information about fracture risk. Current methods are typically performed with 3D acquisitions, which suffer from long scan times and are generally limited to extremities. This work proposes using 2D UTE with half pulses for quantitatively mapping bound and pore water in cortical bone. Methods Half‐pulse 2D UTE methods were implemented on a 3T Philips Achieva scanner using an optimized slice‐select gradient waveform, with preparation pulses to selectively image bound or pore water. The 2D methods were quantitatively compared with previously implemented 3D methods in the tibia in five volunteers. Results The mean difference between bound and pore water concentration acquired from 3D and 2D sequences was 0.6 and 0.9 mol 1 H/L bone (3 and 12%, respectively). While 2D pore water methods tended to slightly overestimate concentrations relative to 3D methods, differences were less than scan‐rescan uncertainty and expected differences between healthy and fracture‐prone bones. Conclusion Quantitative bound and pore water concentration mapping in cortical bone can be accelerated by 2 orders of magnitude using 2D protocols with optimized half‐pulse excitation. Magn Reson Med 77:945–950, 2017. © 2017 International Society for Magnetic Resonance in Medicine.