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3D hyperpolarized He‐3 MRI of ventilation using a multi‐echo projection acquisition
Author(s) -
Holmes James H.,
O'Halloran Rafael L.,
Brodsky Ethan K.,
Jung Youngkyoo,
Block Walter F.,
Fain Sean B.
Publication year - 2008
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.21437
Subject(s) - undersampling , image quality , artifact (error) , real time mri , iterative reconstruction , image resolution , echo (communications protocol) , streak , trajectory , nuclear medicine , computer science , magnetic resonance imaging , physics , artificial intelligence , medicine , image (mathematics) , radiology , optics , computer network , astronomy
A method is presented for high‐resolution 3D imaging of the whole lung using inhaled hyperpolarized (HP) He‐3 MR with multiple half‐echo radial trajectories that can accelerate imaging through undersampling. A multiple half‐echo radial trajectory can be used to reduce the level of artifact for undersampled 3D projection reconstruction (PR) imaging by increasing the amount of data acquired per unit time for HP He‐3 lung imaging. The point spread functions (PSFs) for breath‐held He‐3 MRI using multiple half‐echo trajectories were evaluated using simulations to predict the effects of T 2 * and gas diffusion on image quality. Results from PSF simulations were consistent with imaging results in volunteer studies showing improved image quality with increasing number of echoes using up to 8 half‐echoes. The 8‐half‐echo acquisition is shown to accommodate lost breath‐holds as short as 6 sec using a retrospective reconstruction at reduced resolution and also to allow reduced breath‐hold time compared with an equivalent Cartesian trajectory. Furthermore, preliminary results from a 3D dynamic inhalation‐exhalation maneuver are demonstrated using the 8‐half‐echo trajectory. Results demonstrate the first high‐resolution 3D PR imaging of ventilation and respiratory dynamics in humans using HP He‐3 MR. Magn Reson Med 59:1062–1071, 2008. © 2008 Wiley‐Liss, Inc.