Dynamic MRI of grid-tagged hyperpolarized helium-3 for the assessment of lung motion during breathing.
OBJECTIVE
To develop a dynamic magnetic resonance imaging (MRI) tagging technique using hyperpolarized helium-3 (HP He-3) to track lung motion.


METHODS
An accelerated non-Cartesian k-space trajectory was used to gain acquisition speed, at the cost of introducing image artifacts, providing a viable strategy for obtaining whole-lung coverage with adequate temporal resolution. Multiple-slice two-dimensional dynamic images of the lung were obtained in three healthy subjects after inhaling He-3 gas polarized to 35%-40%. Displacement, strain, and ventilation maps were computed from the observed motion of the grid peaks.


RESULTS
Both temporal and spatial variations of pulmonary mechanics were observed in normal subjects, including shear motion between different lobes of the same lung.


CONCLUSIONS
These initial results suggest that dynamic imaging of grid-tagged hyperpolarized magnetization may potentially be a powerful tool for observing and quantifying pulmonary biomechanics on a regional basis and for assessing, validating, and improving lung deformable image registration algorithms.
Cai
Jing
J
Department of Radiation Oncology, University of Virginia, Charlottesville, VA 22908, USA.
Sheng
Ke
K
Benedict
Stanley H
SH
Read
Paul W
PW
Larner
James M
JM
Mugler
John P
JP
de Lange
Eduard E
EE
Cates
Gordon D
GD
Miller
G Wilson
GW
D000328:Adult; D000465:Algorithms; D005260:Female; D006371:Helium; D006801:Humans; D007554:Isotopes; D008168:Lung / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009068:Movement; D012119:Respiration; D015656:Respiratory Mechanics; D016683:Supine Position; D055815:Young Adult
D007554:Isotopes; D006371:Helium