MRI Assessment of Lung Airways in Cystic Fibrosis: Evaluate MRI's Ability to Detect Changes in Airway Structure .

Group 1 Inclusion Criteria: * Participants must be greater than or equal to 6 years of age and not greater than 18 years of age. * Informed consent by patient or parent/guardian consent and participant assent when appropriate. * Able to perform reproducible spirometry Exclusion Criteria: * Medical instability that would preclude the ability to undergo the required investigations * FEV1 % predicted \< 40% * Severe claustrophobia * Does not meet MRI screening criteria * Usage of oral antibiotics within 3 weeks prior to study visit * Known pulmonary disease Group 2 Inclusion Criteria * Diagnosis of CF as evidenced by one or more clinical feature consistent with the CF phenotype or positive CF newborn screen * Participants must be greater than or equal to 6 years of age and not greater than 18 years of age. * Informed consent by patient or parent/guardian consent and participant assent when appropriate. * Able to perform reproducible spirometry Exclusion Criteria * Medical instability that would preclude the ability to undergo the required investigations * FEV1 % predicted \< 40% * Severe claustrophobia * Does not meet MRI screening criteria * Worsening cough and/or sputum production within the past 3 days prior to study visit * The use of new oral and/or inhaled antibiotics within 3 weeks prior to study visit * Received intravenous antibiotics within 2 weeks prior to study visit * The use of supplementary oxygen * Status of post lung or another organ transplant