19F MRI in Healthy Children and Children With Mild Cystic Fibrosis Lung Disease

Inclusion Criteria: * 6-17 years old * Non-smoker and non-vaper * Cystic Fibrosis (CF) Group: must have a diagnosis of CF * No use of supplemental oxygen * They must be able to perform spirometry and have stable lung function (within 10% personal best in the last 6 months) and no exacerbations within the past 4 weeks * Baseline forced expiratory volume in 1 second (FEV1) \>80% with ratio of the forced expiratory volume in the first one second to the forced vital capacity of the lung (FEV1:FVC) ratio \>0.7 Exclusion Criteria: * Healthy volunteers: with any history of chronic lung disease (i.e. asthma) * Active or former smoker with less than 1 year of quitting * Unable to undergo an MRI of the lungs and chest because of contraindications, including: * Injury to the eye involving a metallic object * Injury to the body involving a metallic object * Presence of an implanted drug infusion device that is not MRI safe * Bone growth of fusion simulator * Presence of cochlear, otologic, or ear implant * Shunt (spinal or intraventricular) * Any implant held in place by magnet * Claustrophobia * Unable to tolerate the inhalation of the gas mixture * Facial hair preventing a tight fit of the mask used in the study * Pregnancy * Changes in medication that may affect CF lung disease or lung function in the past 28 days, including experimental therapies