A new perspective and old problems.
D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008171:Lung Diseases / Q000000981:diagnostic imaging; D008173:Lung Diseases, Obstructive / Q000000981:diagnostic imaging; D011312:Pressure; D011652:Pulmonary Circulation; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging; D014055:Tomography, Emission-Computed; D014692:Ventilation-Perfusion Ratio