Low-attenuation areas of the lungs on high-resolution computed tomography in asthma.
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.
Mitsunobu
F
F
Department of Medicine, Okayama University Medical School, Tottori, Japan. fumin@cc.okayama-u.ac.jp
Mifune
T
T
Ashida
K
K
Hosaki
Y
Y
Tsugeno
H
H
Okamoto
M
M
Harada
S
S
Tanizaki
Y
Y
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
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride; D007073:Immunoglobulin E