Date of Award
Master of Science
Dr. Giles Santyr
In recent years, hyperpolarized noble gas magnetic resonance diffusion measurements have shown remarkable sensitivity for diagnosing emphysema. The apparent diffusion coefficient (ADC) of hyperpolarized gases has also been shown to behave anisotropically in the lung at short diffusion times. In this work, we investigate hyperpolarized Xe gas anisotropic ADCs of the Yablonskiy model in vivo in an elastase-instilled rat model of emphysema. Diffusion simulations in a budded cylinder model estimated that the transverse anisotropic ADC (Dr) may have optimal sensitivity at measuring airways enlargements, and that the optimal diffusion time to measure Dj with xenon is close to 5 ms. Measurements in sham and elastase-instilled rats were performed for a range of diffusion times, and the only significant increase of ADC was observed for Dj at 6 ms (p < 0.005), and a strong correlation between Dj and the mean linear intercepts from lung histology was observed (r = 0.90).
Boudreau, Mathieu, "Hyperpolarized 129Xe Apparent Diffusion Coefficient Anisotropy in an Elastase- Instilled Rat Model of Emphysema" (2011). Digitized Theses. 3397.