Salma Ajraoui1, Juan Parra-Robles1, Martin Deppe1, Kevin Teh1, Steven R. Parnell1, John Owers-Bradley2, Jim M. Wild1
1Academic Unit of Radiology, University of Sheffield, Sheffield, UK; 2School of Physics, University of Nottingham, Nottingham, UK
The diffusion of 3He gas in the complex geometry of the lung deviates from Gaussian behavior. In this work, we investigate experimentally the sources of non-Gaussian behavior (e.g. anisotropy, varying airway sizes, airway interconnectivity) using many b-values in well defined geometric models built from polypropylene tubing and Y-connectors. The deviation from Gaussian behavior was evaluated by fitting the signal decay to Gaussian and kurtosis models. The results suggest that for the models used in this work, the anisotropy is the most important contributor to non-monoexponential diffusion behavior.
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