Assessment of the Progression of Emphysema by Quantitative Analysis of Spirometrically Gated Computed Tomography Images

Abstract

The authors assessed the progression of pulmonary emphysema by means of quantitative analysis of computed tomography images. Twenty-three patients suffering from emphysema due to an α1-antitrypsin deficiency, aged 45 ± 7 years and exsmokers, were scanned twice with a 1-year time interval. At 90% of the vital lung capacity, slices with a thickness of 1.5 mm were acquired at the level of the carina and 5 cm above the carina; slices with a thickness of 1 cm were acquired 5 cm below the carina. The entire lung was scanned spirally at a respiratory status, corresponding with 75% of the total lung capacity at baseline. The mean lung densities (MLD) were calculated in an objective manner with new analytic software featuring automated detection of the lung contours. Mean Lung densities decreased by 14.2 ± 12.0 Hounsfield units (HU; P CONCLUSIONS Progression of emphysema can be assessed in an objective manner based on the mean lung density (MLD), measured from computed tomography volume scans as well as from single-slice scans. Mean lung density has proved to be more sensitive than FEV1 and carbon monoxide-diffusion.