title: Asthma COPD Overlap Syndrome on CT Densitometry: A Distinct Phenotype from COPD.
abstract: Patients with asthma COPD overlap syndrome (ACOS) are an important but poorly characterized group. This study sought to explore the distinct characteristics of ACOS on CT densitometry. The study population was randomly selected from communities via questionnaires. All participants underwent low-dose volumetric chest CT both before and after bronchodilator administration. Each CT scan was performed at full-inspiration and full-expiration for CT densitometry. Emphysema index (EI), air trapping (AT), mean lung density (MLD) and total lung volume (TLV) were measured and compared between the ACOS and COPD groups. The distributions of both EI and AT were compared between patients with ACOS and COPD. The variations between the pre- and post-BD measurements observed in patients with ACOS were compared with those in patients with COPD. A total of 71 patients completed the study, including 32 patients with COPD and 39 patients with ACOS. The patients with ACOS exhibited lower EI and more upper-zone-predominant EI distributions, compared with the patients with COPD. No significant differences were exhibited in AT and its distribution. Following bronchodilator administration, the variations in AT and expiratory MLD were greater in patients with ACOS than in patients with COPD. No differences were observed in the variations of EI and inspiratory MLD. Our results indicate that patients with ACOS have lower extent of emphysema and different emphysema distribution, as well as greater post-BD variations in air trapping, compared with patients with COPD. These findings suggest that CT densitometry characterizes ACOS as a distinct phenotype from COPD.
authors.affiliation: a Department of Radiology, Beijing Chao-Yang Hospital , Capital Medical University , Beijing , People's Republic of China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Gao
authors.affiliation: a Department of Radiology, Beijing Chao-Yang Hospital , Capital Medical University , Beijing , People's Republic of China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhai
authors.affiliation: a Department of Radiology, Beijing Chao-Yang Hospital , Capital Medical University , Beijing , People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Li
authors.affiliation: b Department of Pulmonary and Critical Care Medicine, Beijing Chao-Yang Hospital , Capital Medical University, Beijing Institute of Respiratory Medicine , Beijing , People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: b Department of Pulmonary and Critical Care Medicine, Beijing Chao-Yang Hospital , Capital Medical University, Beijing Institute of Respiratory Medicine , Beijing , People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: b Department of Pulmonary and Critical Care Medicine, Beijing Chao-Yang Hospital , Capital Medical University, Beijing Institute of Respiratory Medicine , Beijing , People's Republic of China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Lu
authors.affiliation: a Department of Radiology, Beijing Chao-Yang Hospital , Capital Medical University , Beijing , People's Republic of China.
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Pan
authors.affiliation: a Department of Radiology, Beijing Chao-Yang Hospital , Capital Medical University , Beijing , People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: b Department of Pulmonary and Critical Care Medicine, Beijing Chao-Yang Hospital , Capital Medical University, Beijing Institute of Respiratory Medicine , Beijing , People's Republic of China.
authors.forename: Kewu
authors.initials: K
authors.lastname: Huang
authors.affiliation: a Department of Radiology, Beijing Chao-Yang Hospital , Capital Medical University , Beijing , People's Republic of China.
authors.forename: Renyou
authors.initials: R
authors.lastname: Zhai
mesh_terms: D000368:Aged; D001249:Asthma / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016022:Case-Control Studies; D003720:Densitometry; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011656:Pulmonary Emphysema / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D013577:Syndrome; D014057:Tomography, X-Ray Computed; D014797:Vital Capacity
keywords: X-ray computed; airtrapping; emphysema; quantitative research; tomography