© 2003 American Thoracic Society
Complexity of Terminal Airspace Geometry Assessed by Computed Tomography in AsthmaDepartment of Medicine, Misasa Medical Branch, Okayama University Medical School, Tottori; and Department of Respiratory Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan Correspondence and requests for reprints should be addressed to Fumihiro Mitsunobu, M.D., Ph.D., Department of Medicine, Misasa Medical Branch, Okayama University Medical School, 827 Yamada, Misasa, Tottori 682–0192, Japan. E-mail: fumin{at}cc.okayama-u.ac.jp Low attenuation areas in computed tomography images from patients with chronic obstructive pulmonary disease have been reported to represent macroscopic and/or microscopic emphysema. The cumulative size distribution of the clusters has been shown to follow a power law characterized by the exponent D, a measure of the complexity of the terminal airspace geometry. We have previously found increased low attenuation areas in nonsmoking subjects with asthma. We examined the size distribution of the clusters in nonsmoking subjects with asthma compared with both nonsmoking control subjects and subjects with asthma with a smoking history. The percentage of lung field occupied by low attenuation areas (LAA%) and D in subjects with asthma with a smoking history differed significantly from nonsmoking subjects with asthma and control subjects. In nonsmoking subjects with asthma, both parameters differed significantly between severe asthma and mild or moderate asthma. The LAA% differed significantly between moderate and mild asthma, but D did not. In mild and moderate asthma, a highly significant correlation between LAA% and D was observed in patients with a smoking history, but not in nonsmoking subjects with asthma. Our results suggest that decreased D is mostly related to emphysematous change, and both measurements of LAA% and D may provide useful information to characterize low attenuation areas in subjects with asthma.
Key Words: asthma • computed tomography • fractals This article has been cited by other articles:
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
