Patsios, D; Bayanati, H; Johnston, M; Paul, N; Roberts, H
Background: We screen prior asbestos workers for the early detection of lung cancer and mesothelioma using low-dose computed tomography (LDCT). For this presentation we analyze the presence of diffuse parenchymal abnormalities.
Methods: Subjects studied had a history of asbestos exposure at least 20 years prior to enrollment and/or demonstration of pleural plaques on chest radiographs. A baseline LDCT of the chest was performed using a multidetector CT scanner with collimation of 1.25mm, 60mAs and 120kV. Focal parenchymal and pleural masses or plaques are reported separatedly. For this analysis, we noted the following 8 interstitial patterns according to their presence, lobar location and extent: inter- and intralobular septal thickening, subpleural ground glass opacities, honeycombing, architectural distortion, subpleural curvilinear lines, parenchymal bands, round atelectasis. In each of the 5 lobes, each pattern was scored as 0 (absence), 1 (within 1 cm from the pleura), 2 (within 2 cm from the pleura) and 3 (more than 2 cm from the pleura), with a maximum score of 120. The presence of emphysema was noted separately.
Results: One hundred subjects (99M, 1F) were scanned between March and September 2005, with a mean age of 60.6 years (50-81), and an average exposure to asbestos of 24.2 years. 65 subjects scored 0 (65%). 35 individuals (35%) demonstrated features of parenchymal lung disease with scores ranging from 1-25: 11/35 showed interlobular septal thickening, 6/35 ground glass opacities, 3/35 honeycombing, 4/35 architectural distortion, 6/35 subpleural lines, 18/35 parenchymal bands, 8/35 round atelectasis. There was lower lobe predominance with 50.4% in both lower lobes, 49.6% in the remaining lungs. 17subjects (17%) demonstrated centrilobular emphysema.
Conclusions: LDCT can demonstrate parenchymal lung disease in this subgroup with a history of asbestos exposure. The presence of subpleural lines, septal thickening, honeycomb formation, architectural distortion and ground glass opacities, although non specific, may entertain asbestosis as an etiology and thus require further diagnostic work up.