title: Aerosols in healthy and emphysematous in silico pulmonary acinar rat models.
abstract: There has been relatively little attention given on predicting particle deposition in the respiratory zone of the diseased lungs despite the high prevalence of chronic obstructive pulmonary disease (COPD). Increased alveolar volume and deterioration of alveolar septum, characteristic of emphysema, may alter the amount and location of particle deposition compared to healthy lungs, which is particularly important for toxic or therapeutic aerosols. In an attempt to shed new light on aerosol transport and deposition in emphysematous lungs, we performed numerical simulations in models of healthy and emphysematous acini motivated by recent experimental lobar-level data in rats (Oakes et al., 2014a). Compared to healthy acinar structures, models of emphysematous subacini were created by removing inter-septal alveolar walls and enhancing the alveolar volume in either a homogeneous or heterogeneous fashion. Flow waveforms and particle properties were implemented to match the experimental data. The occurrence of flow separation and recirculation within alveolar cavities was found in proximal generations of the healthy zones, in contrast to the radial-like airflows observed in the diseased regions. In agreement with experimental data, simulations point to particle deposition concentrations that are more heterogeneously distributed in the diseased models compared with the healthy one. Yet, simulations predicted less deposition in the emphysematous models in contrast to some experimental studies, a likely consequence due to the shallower penetration depths and modified flow topologies in disease compared to health. These spatial-temporal particle transport simulations provide new insight on deposition in the emphysematous acini and shed light on experimental observations.
authors.affiliation: Department of Mechanical Engineering, University of California Berkeley, Berkeley, CA 94709,USA; INRIA Paris-Rocquencourt, 78153 Le Chesnay Cedex, France; Sorbonne Universités, UPMC Univ Paris 6, Laboratoire Jacques-Louis Lions, 75252 Paris, France.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Oakes
authors.affiliation: Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
authors.forename: Philipp
authors.initials: P
authors.lastname: Hofemeier
authors.affiliation: INRIA Paris-Rocquencourt, 78153 Le Chesnay Cedex, France; Sorbonne Universités, UPMC Univ Paris 6, Laboratoire Jacques-Louis Lions, 75252 Paris, France.
authors.forename: Irene E
authors.initials: IE
authors.lastname: Vignon-Clementel
authors.affiliation: Department of Biomedical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel. Electronic address: sznitman@bm.technion.ac.il.
authors.forename: Josué
authors.initials: J
authors.lastname: Sznitman
mesh_terms: D000336:Aerosols; D000818:Animals; D003198:Computer Simulation; D008168:Lung / Q000502:physiology* / Q000503:physiopathology*; D008954:Models, Biological; D010316:Particle Size; D011656:Pulmonary Emphysema / Q000503:physiopathology*; D051381:Rats; D012119:Respiration
chemical_list: D000336:Aerosols
keywords: Alveoli; Computational fluid dynamics (CFD); Disease modelling; Emphysema; Particle deposition