Correlation between pulmonary function and low attenuation area (LAA) on HRCT III patients with asthma in relation to smoking

The influence of smoking on pulmonary function and emphysematous changes of the lung (percentage of attenuation area < -950 HU (% LAA) on high resolution computed tomography (HRCT) was examined in 49 patients with bronchial asthma. 1. In patients with asthma, the % residual volume (RV) in many nonsmokers was less than 129%, in contrast, the % RV in many smokers was between 130% and 189% , which was higher than that in nonsmokers. 2. Significant correlations between % RV and 96LAA value, and between % RV and CT number were observed both in nonsmokers and smokers with asthma, in which as % RV more increased, % LAA value was larger, and CT number was lower. 3. % DLco value was lower in smoking patients with asthma, whose % RV was between 130% and 189% and larger than 190% , however, the % DLco value did not change in nonsmoking patients despite of higher valure in % RV. 4. A significant correlation was also observed between % FEV1.0 value and % RV both in smoking and nonsmoking patients with asthma; as % RV value more increased, % FEV1.0 value was lower. 5. Any correlation between % FVC value and % RV was not observed. These results suggest that smoking affects the % LAA of the lung on HRCT and % DLco in patients with asthma.
気管支喘息49例を対象に､肺機能およびHigh resolution computed tomography(HRCT)上のLow attenuation are (LAA)