Date of Award


Degree Type


Degree Name

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).



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.