Jordan Zach, Presenter: Nothing to Disclose

James R. Murphy, Abstract Co-Author: Nothing to Disclose

Carla G. Wilson, Abstract Co-Author: Nothing to Disclose

John D. Newell MD, Abstract Co-Author: Research Consultant, Siemens AG Research grant, Siemens AG Consultant, WebMD Health Corp (WebMD, Inc) Author, The Humana Press

Joyce Denise Schroeder MD, Abstract Co-Author: Research grant, Siemens AG

Eric A. Hoffman PhD, Abstract Co-Author: Shareholder, VIDA Diagnostics Medical Advisory Board, Siemens AG

David Augustine Lynch MB, Abstract Co-Author: Consultant, Actelion Ltd Research support, Siemens AG Consultant, Gilead Sciences, Inc Consultant, Novartis AG Scientific Advisor, Perceptive Informatics, Inc

The purpose of this study is to evaluate whether quantitative CT (QCT) measures of emphysema, gas trapping and airway wall thickening vary with age, gender, or body mass index (BMI) in healthy non-smoking adults, aged between 45 and 80.

As part of the COPDGene™ study, 99 healthy non-smokers (32 male, 67 female, mean age 62.7 ± s.d. 8.9, mean BMI 28 ± s.d. 5.0) underwent volumetric CT at full inspiration and at the end of a normal expiration. On QCT analysis (Pulmonary Workstation, VIDA Diagnostics), emphysema-like changes were defined as lung tissue with attenuation values ≤ -950 Hounsfield Units (HU) on inspiratory CT. Gas trapping was defined as lung tissue ≤ -856 HU on expiratory CT. Multivariate analysis was used to determine the relationships between age, gender and body mass index (BMI), and QCT parameters.

Mean ( ± s.d.) % emphysema-like changes was 2.0 ± 2.6, and mean % gas trapping was 10.8 ± 9.8. Mean % emphysema-like changes was 3.3 ± 3.3 in men, compared with 1.4 ± 2.1 in women (p=0.002). The % emphysema-like changes decreased slightly with age (p=0.04) and did not change significantly with higher BMI. % gas trapping did not show any relationship with age, gender or BMI. Segmental airway luminal diameter was greater in men than in women, 5.95 ± 0.79mm vs. 5.09 ± 0.49mm respectively (p<0.0001). Segmental airway wall thickness was also significantly greater in men than in women, 1.62 ± 0.17mm vs. 1.46 ± 0.18mm (p<0.0001). Segmental airway measurements did not show a relationship with age or BMI. On multivariate analysis, the relationships between % emphysema-like changes and age and gender, and between segmental wall parameters and gender remained statistically significant.

In normal older non-smoking adults, men have higher % emphysema-like changes and have larger luminal airway diameters and airway wall thickness as compared with women. In contrast to previous studies, greater age was associated with slightly lower emphysema extent, and % gas trapping appears to be relatively independent of age, gender and BMI.

With increasing use of QCT, understanding the normal range of QCT measurements and their variation with age and gender is important for clinical interpretation.

Zach, J, Murphy, J, Wilson, C, Newell, J, Schroeder, J, Hoffman, E, Lynch, D, Quantitative CT of the Lungs and Airways in Healthy Nonsmoking Adults: Relationship to Age, Gender, and Body Mass Index: For the COPDGene™ Study.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9007105.html