Fig. 1

1^st patient. a HRCT scan at the level of the aortic arch. There is a single layer of subpleural cystic air spaces with no or barely discernible walls that are characteristically bounded by the pleural surface and the interlobular septa. This corresponds to the diagnosis of paraseptal emphysema. b HRCT scan at the level of the dome of the right hemidiaphragm. There is honeycombing (cystic airspaces with well defined walls that are clustered in several layers) with a clear subpleural/peripheral distribution, fulfilling the criteria of definitive UIP pattern