1. A method for assessing an efficacy of a treatment for a respiratory condition in a subject comprising the steps of: a) obtaining data concerning a pre-treatment three-dimensional image of a respiratory system of the subject, and a post-treatment three-dimensional image of the respiratory system of the subject, b) calculating a specific three-dimensional structural model of a lung structure of the subject from each of the pre- and post-treatment image data obtained in step a), c) calculating a specific three-dimensional structural model of an airway structure of the subject from each of the pre- and post-treatment image data obtained in step a), d) calculating a patient-specific three-dimensional structural model of a lobar structure of the subject from each of the pre- and post-treatment lung structure models obtained in step b), e) modeling by a computer, air flow through the airway structure at pre- and post-treatment states, using the respective pre- and post-treatment models of the airway structure and lobar structure of the subject obtained in steps c) and d); f) modeling by a computer, structural behavior of the airway structure and the interaction with the air flow at pre- and post-treatment states, using the respective pre- and post-treatment models of the airway structure and lobar structure of the subject obtained in steps c) and d); g) comparing the modeled air flow pre- and post-treatment and comparing the structural behaviour pre- and post-treatment to determine the efficacy of the treatment, wherein an efficacious treatment is one that decreases airway resistance, thereby increasing lobar mass for a same driving pressure, thereby determining the efficacy of the treatment for the respiratory condition.