The purpose of this study is to compare the performances of ultra-low dose computed tomography (CT) and lung magnetic resonance imaging (MRI) for morphological assessment of cystic fibrosis-related lung disease and to compare their performances to conventional low dose CT

Cystic fibrosis (CF) is a recessive autosomal disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that encodes for an epithelial chloride channel involved in ion and fluid transport. CF is the most common inherited disease in Caucasians and disease severity mainly depends on the degree of lung involvement, which can lead to terminal respiratory failure Disease monitoring of CF-related lung disease rely on functional assessment and complimentary morphological assessment. Conventional low-dose chest computed tomography (CT) is currently the gold standard for the morphological assessment of CF-related lung disease but ultra-low dose chest CT and high-resolution magnetic resonance imaging (MRI) of the lung using UTE sequences have been recently developed and allow important radiation reduction of radiation dose exposure. However the performances of these 2 competing imaging methods remains to be compared.

Inclusion Criteria:

• Age ≥ 18 year-old
• Diagnosis of cystic fibrosis provided by genetic and swear test
• Chest CT acquisition performed as part of the standard follow-up
• Patient with social security or health insurance
• Informed consent

Exclusion Criteria:

• MRI contraindication
• Orthopnea
• Inability to hold breath for 17 seconds
• No spirometry planned the same day
• Lung transplant patient