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High spatial resolution hyperpolarized 3 He MRI of the rodent lung using a single breath X‐centric gradient‐recalled echo approach
Author(s) -
Ouriadov Alexei V.,
Santyr Giles E.
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.26602
Subject(s) - gradient echo , nuclear magnetic resonance , echo (communications protocol) , resolution (logic) , spin echo , magnetic resonance imaging , lung , physics , echo planar imaging , image resolution , nuclear medicine , medicine , radiology , optics , computer science , artificial intelligence , computer network
Purpose Hyperpolarized (HP) gas MRI of the rodent lung is of great interest because of the increasing need for novel biomarkers with which to develop new therapies for respiratory diseases. The use of fast gradient‐recalled echo (FGRE) for high‐resolution HP gas rodent lung MRI is challenging as a result of signal loss caused by significant diffusion weighting, particularly in the larger airways. In this work, a modified FGRE approach is described for HP 3 He rodent lung MRI using a centric‐out readout scheme (ie, x‐centric), allowing high‐resolution, density‐weighted imaging. Methods HP 3 He x‐centric imaging was performed in a phantom and compared with a conventional partial‐echo FGRE acquisition for in‐plane spatial resolutions varying between 39 and 312 µm. Partial‐echo and x‐centric acquisitions were also compared for high spatial‐resolution breath‐hold (1 s) imaging of rodent lungs. Results X‐centric provided improved signal‐to‐noise ratio efficiency by a factor of up to 13/1.7 and 6.7/1.8, compared with the partial‐echo FGRE for the airways/parenchyma of mouse and rat, respectively, at high spatial resolutions in vivo (<78 µm). In particular, rodent major airways with less restricted diffusion of 3 He could only be visualized with the x‐centric method. Conclusions The x‐centric method significantly reduces diffusion weighting, allowing high spatial and temporal resolution HP 3 He gas density‐weighted rodent lung MRI. Magn Reson Med 78:2334–2341, 2017. © 2017 International Society for Magnetic Resonance in Medicine.