1. Department of Radiology, Hôpital Erasme, Université libre de Bruxelles, Rte de Lennik 808, B-1070 Brussels, Belgium.
2. Department of Pneumology, Hôpital Erasme, Université libre de Bruxelles, Brussels, Belgium.
3. Department of Radiology, Clinique des Grangettes–Genève, Chêne-Bougeries, Switzerland.