Current Smoking Status Is Associated With Lower Quantitative CT Measures of Emphysema and Gas Trapping
- Authors
- Zach, Jordan A.; Williams, Andre; Jou, Sung-Shiick; Yagihashi, Kunihiro; Everett, Douglas; Hokanson, John E.; Stinson, Douglas; Lynch, David A.
- Issue Date
- Jan-2016
- Publisher
- Lippincott Williams & Wilkins Ltd.
- Keywords
- air trapping; smoking; emphysema; chronic obstructive pulmonary disease; quantitative computed tomography
- Citation
- Journal of Thoracic Imaging, v.31, no.1, pp 29 - 36
- Pages
- 8
- Journal Title
- Journal of Thoracic Imaging
- Volume
- 31
- Number
- 1
- Start Page
- 29
- End Page
- 36
- URI
- https://scholarworks.bwise.kr/sch/handle/2021.sw.sch/9468
- DOI
- 10.1097/RTI.0000000000000181
- ISSN
- 0883-5993
1536-0237
- Abstract
- Purpose: The purposes of this study were to evaluate the effect of smoking status on quantitative computed tomography CT measures of low-attenuation areas (LAAs) on inspiratory and expiratory CT and to provide a method of adjusting for this effect. Materials and Methods: A total of 6762 current and former smokers underwent spirometry and volumetric inspiratory and expiratory CT. Quantitative CT analysis was completed using open-source 3D Slicer software. LAAs were defined as lung voxels with attenuation values <=-950 Hounsfield units (HU) on inspiratory CT and <=-856 HU on expiratory CT and were expressed as percentage of CT lung volume (%LAA(I-950) and %LAA(E-856)). Multiple linear regression was used to determine the effect of smoking status on %LAA(I-950) and %LAA(E-856) while controlling for demographic variables, spirometric lung function, and smoking history, as well as total lung capacity (%LAA(I-950)) or functional residual capacity (%LAA(E-856)). Quantile normalization was used to align the %LAA(I-950) distributions for current and former smokers. Results: Mean %LAA(I-950) was 4.2 +/- 7.1 in current smokers and 7.7 +/- 9.7 in former smokers (P < 0.001). After adjusting for confounders, %LAA(I-950) was 3.5 percentage points lower and %LAA(E-856) was 6.0 percentage points lower in current smokers than in former smokers (P < 0.001). After quantile normalization, smoking status was an insignificant variable in the inspiratory regression model, with %LAA(I-950) being 0.27 percentage points higher in current smokers (P=0.13). Conclusions: After adjusting for patient demographics and lung function, current smokers display significantly lower %LAA(I-950) and %LAA(E-856) than do former smokers. Potential methods for adjusting for this effect would include adding a fixed value (eg, 3.5%) to the calculated percentage of emphysema in current smokers, or quantile normalization.
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Collections - College of Medicine > Department of Radiology > 1. Journal Articles
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