Juan Parra-Robles1, Salma Ajraoui1, Martin H. Deppe1, Steven R. Parnell1, Jim M. Wild1
1Unit of Academic Radiology,
In this work, the limits of validity of physical basis of a model of 3He MR lung diffusion are investigated experimentally in simple geometric models. The experimental results have highlighted limitations of the cylinder model. Breakdown of the Gaussian phase approximation was experimentally demonstrated for gradient strengths commonly used in lung ADC experiments, as the localized diffusion regime is approached. The physical assumptions of the cylinder model are only valid if the localized diffusion regime and its neighboring intermediate regimes are avoided.