Aims: Irreversible bronchial dilatation on computed tomography (CT) is seen in patients with interstitial pulmonary fibrosis whereas reversible dilatation of the bronchi is a feature of many conditions. The aim of this study was to determine whether airways dilatation, which is a frequent finding in adult respiratory distress syndrome (ARDS), is reversible and to establish whether persistent airways dilatation is accompanied by other CT signs of established interstitial fibrosis.
Method: Thin section CT scans of 16 patients with ARDS were analysed at a lobar level in the acute phase of the disease and at follow-up (median interval 6.3 months) for the presence and extent of a ground-glass pattern, reticular or linear opacities and the presence or absence of bronchial dilatation.
Results: 95 out of 96 (99%) lobes on the initial CT scan showed ground-glass pattern. Airway dilatation was present in 65 of 95 (68%) of these lobes. On follow-up CT the airways remained dilated in 60 of 65 (92%) lobes and, in the majority of these, 53 of 60 (88%), a reticular and linear pattern with associated distortion had developed. A coexisting ground-glass pattern was present in 12 of 60 (20%) lobes on follow-up CT, but was the sole residual abnormality in only one lobe.
Conclusion: In patients with ARDS, dilatation of the airways within areas of ground-glass pattern is a frequent observation in the acute phase of the condition and tends to persist at follow-up, usually accompanied by the CT features of supervening pulmonary fibrosis.