RT Journal Article SR Electronic T1 Modelling of 3He gas diffusion in realistic 3D models of human acinar airways obtained from micro-CT images JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P4972 VO 44 IS Suppl 58 A1 Juan Parra-Robles A1 Dragos Vasilescu A1 James C. Hogg A1 Jim M. Wild YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P4972.abstract AB Introduction: Theoretical models of gas diffusion can provide information about lung microstructure from hyperpolarized 3He MRI. Current models are based on computational simulation in simplified geometries that do not reflect the complex geometry of acinar airways.Objective: To develop a new framework for computer simulations of 3He diffusion in realistic 3D models of acinar airways generated from microCT images.Methods: 3D MicroCT images of samples of human lungs obtained in a previous study (McDonough et al NEJM 2011) were segmented to produce a 3D airways model. Simulations of gas diffusion were performed using finite element solution of the Bloch-Torrey diffusion MR equation [Parra-Robles and Wild, J Magn Res 2013]Results: Figure 1 shows microCT data (A), corresponding to a typical 3He MRI voxel size (7x7x7mm) and the segmented volume from a single acinus (D). A cross-section of segmented airspace mask (C) and a 3D 3He diffusivity distribution map (cm2/s) obtained from the computer simulations (D) are also shown. The diffusivity values are similar to those measured in vivo with 3He MRI. These results showed effects from branching geometry and localized diffusion that are not accounted for in current simple geometric models.Conclusion: MicroCT images can be used to generate models of acinar airways which allow computer simulations of gas diffusion which account for the complexity of lung microstructure.