PROGRESS OF EMPHYSEMA IN SEVERE ALPHA(1)-ANTITRYPSIN DEFICIENCY AS ASSESSED BY ANNUAL CT

Purpose: To assess serial CT as a measure of the progress of emphysema in patients with severe alpha(1)-antitrypsin deficiency (phenotype Pi Z). Material and Methods: In a randomized placebo-controlled study of alpha(1)-antitrypsin augmentation therapy, 22 patients with moderate e mphysema were followed for 2-4 years with an annual lung CT. The image s were analysed by means of semiautomatic lung detection, and the degr ee of emphysema was quantitated by the density-mask and the percentile methods. The influence of lung volume was standardised by a regressio n model. Results: A highly significant decline in Hounsfield units (HU ) was found in low-density areas, corresponding to a mean (SE) annual loss of lung tissue of 2.1 (0.4) g/l lung volume. Analysis of a single slice at 5 cm below the level of the carina gave comparable results: 2.3 (0.4) g/l. Conclusion: Serial CT is a sensitive measure of the pro gress of emphysema in patients with severe alpha(1)-antitrypsin defici ency.