title: Frequency-dependent changes of gas distribution revealing early mechanical alterations in human lungs.
mesh_terms: D000328:Adult; D000403:Airway Resistance; D001991:Bronchitis / Q000175:diagnosis; D002908:Chronic Disease; D005260:Female; D006112:Gravitation; D006371:Helium; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008170:Lung Compliance; D008297:Male; D012129:Respiratory Function Tests; D012907:Smoking
chemical_list: D006371:Helium