1. Department of Radiology, Royal Brompton Hospital, London SW3 6NP, UK
2. The Interstitial Lung Disease Unit, Royal Brompton Hospital, London SW3 6NP, UK
3. The National Heart & Lung Institute, Imperial College London, London W12 7RQ, UK
4. The Margaret Turner-Warwick Centre for Fibrosing Lung Diseases, Imperial College London, London W12 7RQ, UK