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Rapid imaging of hyperpolarized gas using EPI
Author(s) -
Saam Brian,
Yablonskiy Dmitriy A.,
Gierada David S.,
Conradi Mark S.
Publication year - 1999
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/(sici)1522-2594(199909)42:3<507::aid-mrm13>3.0.co;2-u
Subject(s) - flip angle , nuclear magnetic resonance , voxel , magnetic resonance imaging , image quality , pulse sequence , chemistry , biomedical engineering , nuclear medicine , materials science , physics , medicine , radiology , computer science , artificial intelligence , image (mathematics)
Rapid repetitive MRI of hyperpolarized (HP) gases using echo‐planar imaging (EPI) has been theoretically investigated and experimentally demonstrated for 3 He in human lung. A quantitative treatment of signal attenuation and magnetization consumption for the unique circumstance of a rapidly diffusing nonrenewable magnetization source has been performed. Rapid (compared to the human respiratory cycle) and repetitive imaging of the lung gas space with EPI and a single delivered bolus of HP‐ 3 He is feasible using low flip angles, provided the voxels are not too small. A coarse‐grid (32 × 64) EPI pulse sequence has been developed and implemented to image the lungs of healthy volunteers during rebreathing of a HP‐ 3 He/N 2 gas mixture. A set of three 10‐mm axial slices was imaged every 0.12 sec for the 36 sec duration of rebreathing, yielding a real‐time visualization of ventilation. Despite some mild artifacts, the images are of good quality and show changes in gas density related to respiratory physiology. Magn Reson Med 42:507–514, 1999. © 1999 Wiley‐Liss, Inc.