Generation of an anatomically based three-dimensional model of the conducting airways

An anatomically accurate model of the conducting airways is essential for a dequately simulating gas mixing, particle deposition, heat and water transf er, and fluid distribution. We have extended a two-dimensional tree-growing algorithm to three dimensions for generation of a host-shape dependent thr ee-dimensional conducting airway model. Terminal branches in the model are both length limited and volume-supplied limited. A limit is imposed on the maximum possible branch angle between a daughter and parent branch. Compari son of the resulting model with morphometric data shows that the algorithm produces branching and length ratios, path lengths, numbers of branches, an d branching angles very close to those from the experimental data. The corr elation between statistics from the generated model and those from morphome tric studies suggests that the conducting airway structure can be described adequately using a "supply and demand" algorithm. The resulting model is a computational mesh that can be used for simulating transport phenomena. (C ) 2000 Biomedical Engineering Society. [S0090-6964(00)00207-1].