Ren Yuan MD, Presenter: Nothing to Disclose

Harvey Owen Coxson PhD, Abstract Co-Author: Research grant, GlaxoSmithKline plc Contract, GlaxoSmithKline plc Contract, Spiration, Inc Research grant, Wyeth

John R. Mayo MD, Abstract Co-Author: Nothing to Disclose

James Hogg MD, Abstract Co-Author: Research grant, GlaxoSmithKline plc

Don D Sin MD, Abstract Co-Author: Nothing to Disclose

Peter D Pare MD, Abstract Co-Author: Research grant, GlaxoSmithKline plc

Chest CT has been widely used to evaluate lung parenchyma and airways in cross-sectional studies. However, there have been very few reports on longitudinal changes in emphysema and airway dimensions, as quantitatively assessed by CT in smokers. The purpose of this study was to investigate the annual changes in airway dimensions and lung attenuation using thin section CT in smokers at different stages of COPD, and to evaluate the correlations between annual changes in CT and spirometry measurements.

One hundred and ninety heavy smokers with ≥ 30 pack years smoking history underwent sequential examination (2~5 visits) using CT and spirometry tests over a mean period of 3.0 years. At baseline, 48 smokers had established COPD (65% male; mean age 63±7 [SD] yrs; mean FEV1%predicted 62±22% [SD], mean FEV1/FVC 57±11% [SD]), and 142 smokers had normal airflow, (i.e., formerly stage 0) (Rabe et al AJRCCM 2007) (54% male; mean age 60±6 [SD] yrs; mean FEV1%predicted 99±13% [SD], mean FEV1/FVC 78±4% [SD]). A multislice CT scan was acquired in the volume scan mode at suspended full inspiration with subject in the supine position. Custom software was used to measure the percent lung low attenuation area (%LAA) less than -950HU, and airway dimensions were measured using the “full width at half maximum” method.

In smokers with established COPD, mean annual decline in FEV1 was 41 mL; annual change in %LAA (-950HU) was 0.7%, and there was a significantly inverse correlation between the two changes (p<0.001). In smokers at stage 0, mean annual decline in FEV1 was 90 mL; annual change in %LAA (-950HU) was 0.14%. However, the change in FEV1 was only positively associated with the changes in airway lumen area (p=0.028) in stage 0 smokers.

CT is a useful tool to quantify the progression of emphysema and airway abnormalities longitudinally. The combination of lung structural changes assessed by CT and lung functional changes provides a comprehensive profile of the nature history of COPD. Smoker initially at stage 0 demonstrated a more rapid decline in FEV1 compared to those with established COPD; as well as a significant progression in pulmonary emphysema detected by CT.

These data provide evidence of disease progression in those smokers initially at a very early stage of COPD, thereby highlighting the need for early intervention in such smokers.

Yuan, R, Coxson, H, Mayo, J, Hogg, J, Sin, D, Pare, P, Longitudinal Follow-up Study of Lungs in Heavy Smokers with CT and in Correlation with Spirometry Measurements  .  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9009161.html