High-resolution CT of asbestosis and idiopathic pulmonary fibrosis

OBJECTIVE. We studied high-resolution CT of asbestosis and idiopathic pulmonary fibrosis to determine whether differences-other than the frequency of associated pleural changes-could be discerned between the two diseases. MATERIALS AND METHODS. High-resolution CT scans of 80 patients with asbestosis and 80 patients with idiopathic pulmonary fibrosis were retrospectively reviewed. Two chest radiologists assessed the type and distribution of parenchymal and pleural abnormalities on high-resolution CT. RESULTS. Subpleural dotlike or branching opacities (65/80), subpleural curvilinear lines (55/80), mosaic perfusion (39/80), and parenchymal bands (38/80) were more common in patients with asbestosis (p < 0.0001). Visible intralobular bronchioles (62/80), bronchiolectasis within fibrotic consolidations (47/80), and honeycombing (61/80) were more common in patients with idiopathic pulmonary fibrosis (p < 0.0001). The frequencies of interlobular septal thickening, ground-glass opacities, fibrotic consolidation, and emphysema were similar in both groups. Parenchymal bands and fibrotic consolidation were more commonly seen (P < 0.05) in patients with asbestosis associated with pleural disease (n = 66) than in patients with asbestosis without pleural disease (n = 14). Also, statistically significant differences were noted between high-resolution CT findings of patients with asbestosis without pleural disease and those of patients with idiopathic pulmonary fibrosis, except for parenchymal bands. CONCLUSION. Specific combinations of high-resolution CT findings strongly suggest either asbestosis or idiopathic pulmonary fibrosis. We found that CT findings that might have represented bronchiolar obstruction in the subpleural region were more prominent in patients with asbestosis than in those with idiopathic pulmonary fibrosis, whereas bronchiolar dilatation was more prominent in patients with idiopathic pulmonary fibrosis than in those with asbestosis.