1. From the Department of Radiology, Royal Brompton Hospital, Sydney St, London SW3 6NP, England (A.D.); Department of of Radiology and Nuclear Medicine, Radboud UMC, Nijmegen, the Netherlands (B.v.G.); Department of Radiology, Guy’s & St Thomas’ NHS Foundation Trust, London, England (A.N.); and Department of Respiratory Medicine, Nottingham University Hospitals and University of Nottingham, Nottingham, England.