Studies of Weakly Restricted Diffusion Using Hyperpolarized 3He Gas in Cylindrical Cells

Pierre-Jean Nacher¹, Kajum Safiullin¹, Genevive Tastevin¹

Diffusive motion of nuclei during signal acquisition has a strong impact on lung imaging with hyperpolarized helium-3. Since air space dimensions range from hundreds of microns (alveoli) to centimeters (main bronchi), free diffusion, motional averaging, or localization regimes can be encountered depending on sequence parameters and on location within the lung. We report on MR relaxometry and 1-D imaging experiments in hyperpolarized 3He confined in sealed glass cells with gas filling pressures, dimensions, and aspect ratios that allow investigations in the (weakly) restricted diffusion met in all airways larger than the acinar ones.