Jonathan Corne, MA, PhD, MB, BS, FRCP, Consultant Respiratory Physician, Nottingham University, Hospitals NHS Trust, Nottingham, Head of the East Midlands Postgraduate Specialty School of Medicine, Health Education East Midlands, UK, Maruti Kumaran, MD, FRCR, Consultant Radiologist, Nottingham University Hospitals, NHS Trust, Nottingham, UK.