Dynamic MRI of grid-tagged hyperpolarized helium-3 for the assessment of lung motion during breathing.

PURPOSE: To develop a dynamic magnetic resonance imaging (MRI) tagging technique using hyperpolarized helium-3 (HP He-3) to track lung motion. METHODS AND MATERIALS: 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. CONCLUSION: 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.

Duke Scholars

Author Jing Cai Radiation Oncology