title: Low-attenuation areas of the lungs on high-resolution computed tomography in asthma.
abstract: To investigate the low-attenuation areas of the lungs (LAA) in asthma, we compared the mean lung density (MLD) and the LAA in 22 asthmatics (12 ex-smokers and 10 nonsmokers) and 13 patients with chronic obstructive pulmonary disease (COPD) by high-resolution computed tomography. The MLD and the relative area of the lung with attenuation values lower than -950 Hounsfield Units at full inspiration (inspiratory RA950) were significantly different in nonsmoking asthmatics compared to patients with COPD and asthmatics with a smoking history. The MLD and the RA950 correlated significantly with the FEV1 in all groups and with the DL(CO) in patients with COPD and asthmatics with a smoking history but not in nonsmoking asthmatics. We concluded that the LAA in asthmatics with a smoking history indicates the presence of emphysema, but in nonsmoking asthmatics it reflects hyperinflation and nonemphysematous expiratory airflow limitation rather than emphysematous lesions.
authors.affiliation: Department of Medicine, Okayama University Medical School, Tottori, Japan. fumin@cc.okayama-u.ac.jp
authors.forename: F
authors.initials: F
authors.lastname: Mitsunobu
authors.forename: T
authors.initials: T
authors.lastname: Mifune
authors.forename: K
authors.initials: K
authors.lastname: Ashida
authors.forename: Y
authors.initials: Y
authors.lastname: Hosaki
authors.forename: H
authors.initials: H
authors.lastname: Tsugeno
authors.forename: M
authors.initials: M
authors.lastname: Okamoto
authors.forename: S
authors.initials: S
authors.lastname: Harada
authors.forename: Y
authors.initials: Y
authors.lastname: Tanizaki
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D001249:Asthma / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008173:Lung Diseases, Obstructive / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008297:Male; D016210:Methacholine Chloride / Q000008:administration & dosage; D008875:Middle Aged; D013147:Spirometry; D014057:Tomography, X-Ray Computed
chemical_list: D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D007073:Immunoglobulin E