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Finite‐difference simulations of 3 He diffusion in 3D alveolar ducts: Comparison with the “cylinder model”
Author(s) -
Fichele Stanislao,
Paley Martyn N.J.,
Woodhouse Neil,
Griffiths Paul D.,
van Beek Edwin J.R.,
Wild Jim M.
Publication year - 2004
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20213
Subject(s) - cylinder , diffusion , physics , nuclear magnetic resonance , materials science , mechanics , nuclear medicine , nuclear physics , mathematics , geometry , medicine , thermodynamics
Time‐dependent measurements of 3 He diffusion in the lung could provide an accurate method to quantify alveolar length scales and the progression of diseases such as emphysema. However, the apparent diffusion coefficient (ADC) presents a complex problem to model and solve analytically. Here, finite‐difference methods were used to simulate diffusion in 3D alveolar ducts. The results were compared to the only available analytical model—the “cylinder model”—from which it is possible to estimate the average radii of the alveolar ducts from in vivo data. The trend in data observed from simulations was found to agree well with the cylinder model. However, the cylinder model always overestimated the average radii of the simulated alveolar ducts. The simulations also demonstrated that the measurement of the longitudinal ADC (along the alveolar ducts) should be sensitive to early emphysematous changes, whereas the measured radii should be far less sensitive. Magn Reson Med 52:917–920, 2004. © 2004 Wiley‐Liss, Inc.