MR Imaging of Lung in the Follow-up Assessment of Cystic Fibrosis

Cystic fibrosis (CF) is caused by the cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation and represents one of the most frequent and lethal inherited disease in Caucasian. However, thanks to better treatments that slow down the progression of pulmonary disease, the median life expectancy has reached 41 years and there are nowadays more CF patients older than 18-year-old than younger. Chronic lung disease is the main manifestation and represents more than 90% of CF morbidity and mortality. However, there is a need for biomarkers more sensitive than clinical and functional findings for a personalized management of patients. Computed tomography (CT), owing to its high spatial resolution and contrast, is the standard of reference in imaging for depicting lung structural alterations. But CT is an ionizing technique, rising concern in cancer risk associated to cumulated radiation dose. To date, Magnetic Resonance Imaging (MRI) is a radiation-free technique which has been demonstrated to add meaningful functional information that cannot be reached using CT. Recent advances in 3-dimensional ultra-short echo time (3D-UTE) imaging have been shown promising to improve lung MR imaging quality. A clear delineation between airway wall and lumen was obtained, thanks to submillimeter voxel size, enabling readers to estimate both bronchial thickening and dilatation with very good concordance with CT, independently from the magnitude of score. The combination of pulse sequence may rather benefit from the potential of MRI to get more complete insight into inflammatory processes by combining several contrasts, as compared to other ionizing methods. Novel MR methods have been shown promising in assessing lung changes with high resolution and therefore could be proposed instead of CT for radiation- free repeated, life-long follow-up