Patient outcome in CF lung transplantation are heavily related to early detecting and treating complications. The surveillance of transplanted patients includes as imaging technique lung CT scans periodically done. Patients in this way are exposed to an ionizing burden and a less invasive technique would be searched. This project aims to study if the multivolume proton-MRI, a new radiation-free imaging method, may be used instead of CT scans and moreover if it offers some advantage in detecting early functional alterations induced by acute lung allograft dysfunction after lung transplantation. CF patients from the Transplant Center in Milan after transplantation will be subjected, in a 24-month study, to the usual surveillance protocol at 3, 6 and 12 months. At these time points, and on the occasion of a clinical/functional suspicion of complications, patients will perform MRI and CT scans on the same day. Their results will be compared and related to pulmonary function tests, clinical indicators and trans-bronchial lung biopsies. The final aim is to validate and introduce a non-invasive method for surveillance of transplanted lungs.