Method for determining a respiratory condition based on functional respiratory imaging

A method for determining lung function in a subject suffering from a respiratory condition, the method comprising the steps of:

• a) obtaining image data concerning two or more three-dimensional computed tomography (CT) images of the subject's respiratory system, wherein the images are acquired during an assessment period comprising a breathing cycle, and wherein the breathing cycle comprises at least functional residual capacity (FRC) and total lung capacity (TLC);
• b) calculating a specific three-dimensional structural model of the subject's respiratory system for each of the two or more three-dimensional images of step a), the specific three-dimensional structural model of the subject's respiratory system comprising a three-dimensional structural model of the subject's lobar structure at each of TLC and FRC, and a three-dimensional structural model of the subject's airway structure at each of TLC and FRC, wherein step b) further comprises the steps of:
• b′) modeling, by a computer, an air flow through the subject's airway structure by determining a mass flow rate towards each lobe of the subject's lobar structure, using the three-dimensional structural models of the subject's lobar structure, and, using the determined mass flow rates as boundary conditions, performing computational fluid dynamic (CFD) numerical analysis using Navier-Stokes equations to model the air flow;
• b″) modeling, by the computer, a structural behavior of the subject's airway structure and an interaction of the airway structure with the air flow, using the three-dimensional structural models of the subject's lobar structure and the three-dimensional structural models of the subject's airway structure;
• and
• b′″) calculating one or more outcome parameters from b′) and b″) for each of the specific three-dimensional structural models of the subject's respiratory system, wherein the one or more outcome parameters comprises lobar blood vessel volume, and optionally one or more of lobar volume, airway volume, airway wall thickness, and airway wall resistance;
• and
• c) determining a respiratory condition by comparing the outcome parameters at step b′″) at TLC and at FRC.