Xenon-129 and Inert Fluorinated Gas Lung MRI: Study of Healthy Volunteers and Participants With Pulmonary Disease

Inclusion Criteria: 1. Participants male and female aged 8 years old and older. 2. Participants have no smoking history. 3. For participants with CF and asthma, a clinical diagnosis is necessary and they should be at their baseline level of symptom control based on history. 4. Participants should have a FEV1%pred value greater than 40%. 5. Participant understands the study procedures and is willing to participate in the study as indicated by signature on the informed consent or assent. 6. Participant must be able to perform a breath hold for 20s or less. 7. Participant able to perform reproducible pulmonary function tests (i.e., the 3 best acceptable spirograms have FEV1 values that do not vary more than 5% of the largest value or more than 100 ml, whichever is greater). For the PEx sub-cohort, admission to the Hospital for Sick Children for a pulmonary exacerbation (based on clinical or pulmonary function assessment). Children who will be admitted and then discharged on home IV antibiotics may also be included in this study. Exclusion Criteria: 1. Participant is, in the opinion of the investigator, mentally or legally incapacitated, preventing informed consent/assent from being obtained, or cannot read or understand the written material. 2. Participant has a history of cardiovascular disorders including coronary insufficiency, cardiac arrhythmias, severe hypertension. 3. Other than for the PEx sub-cohort, participant has had a cold or respiratory infection in the last four weeks. 4. Participant requires supplemental oxygen or has a daytime room air oxygen saturation ≤ 95%. 5. Participant is unable to perform spirometry or plethysmography maneuvers. 6. Participant is pregnant or lactating. 7. In the investigator's opinion, participant suffers from any physical, psychological or other condition(s) that might prevent performance of the MRI, such as severe claustrophobia. 8. Participant has an MRI incompatible device or any metal in their body which cannot be removed, including but not limited to pacemakers, neurostimulators, biostimulators, implanted insulin pumps, aneurysm clips, bio prosthetic, artificial limb, metallic fragment or foreign body, shunt, surgical staples (including clips or metallic sutures and/or ear implants). \-