The present invention relates to a method of characterising lung function ina subject in need of such characterisation. The method comprises performingan imaging technique, on a voxel defined within a lung space of interest. Imagedata is generated over a time period during which the subject inhales gases withat least two different partial pressures of a paramagnetic gas. A compartmentalmodel algorithm is applied to the image data generated for the voxel to provideinformation on ventilation, diffusion and perfusion of a lung. The paramagneticgas is preferably Oxygen. The imaging technique is preferably Oxygen EnhancedMagnetic Resonance Imaging (OE-MRI).
