Dynamic 19F MRI for Cystic Fibrosis Lung Function

Inclusion Criteria: 1. Subjects must be ≥18 years of age 2. Non-smokers (\<10 pack/year history and no active smoking in the past year) 3. Diagnosis of cystic fibrosis via standard sweat chloride/phenotypic features/genotyping 4. No use of supplemental oxygen 5. Stable lung function (within 10% of personal best in the last 6 months) with no pulmonary exacerbations in the past 4 weeks and baseline FEV1≥60% of predicted 6. Evidence of a personally signed and dated consent indicating that the subject has been informed of all pertinent aspects of the trial 7. Subjects must be willing and able to comply with scheduled visits and other trial procedures Exclusion Criteria: Subjects presenting with any of the following will not be included in the trial: 1. Active or past smokers or vapers with less than 1 year since quitting or \>10 pack-year smoking history 2. Unable to undergo a 3.0-Tesla MRI exam of the lungs and chest because of contraindications including 1. Occupation (past or present) of machinist, welder, or grinder; 2. Injury to the eye involving a metallic object 3. Injury to the body by a metallic object (bullet, bullet ball, shrapnel) 4. Presence of a cardiac pacemaker or defibrillator 5. Presence of aneurysm clips 6. Presence of carotid artery vascular clamp 7. Presence of neurostimulator 8. Presence of insulin or infusion pump 9. Presence of implanted drug infusion device that is not known to be MRI compatible (i.e., was placed outside of UNC or is older than 10 years) 10. Bone growth or fusion simulator 11. Presence of cochlear, otologic or ear implant 12. Any type of prosthesis (eye, penile, etc.) 13. Artificial limb or joint 14. Non-removable electrodes (on body, head or brain) 15. Intravascular stents, filters or coils 16. Shunt (spinal or intraventricular) 17. Swan-Ganz catheter 18. Any implant held in place by a magnet 19. Transdermal delivery system (e.g. Nitro) 20. An intrauterine device or diaphragm that is not MRI compatible 21. Tattooed makeup (eyeliner, lips, etc.) or tattoos covering \>25% of body surface area 22. Body piercings (must be removed before MRI) 23. Any metal fragments 24. Internal pacing wires 25. Metal or wire mesh implants 26. Hearing aid (remove before MRI) aa. Dentures (remove before MRI) bb. Claustrophobia 3. Unable to tolerate inhalation of gas mixture 4. Presence of facial hair that may interfere with the fit of the mask (and unwillingness to shave prior to each MRI) 5. Any changes in medications that may affect CF lung disease in the past 28 days, including any experimental therapies 6. Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with trial participation or may interfere with the interpretation of trial results and, in the judgment of the investigator, would make the subject inappropriate for entry into this trial. 7. Pregnancy; women of childbearing potential must have a confirmed negative urine pregnancy test on the day of the MR scan, prior to the MRI scan.