Chronic Lung Allograft Dysfunction MRI Study

All subjects-Inclusion Criteria: * Ages 18-80 * English Speaking Subjects * Willingness and ability to provide informed consent * Non-smoker Lung transplant patients-inclusion criteria: * \>/= 6 months from lung transplant * History of bilateral lung transplant CLAD-free patients-inclusion criteria: * Stable spirometry with FEV1 \> 90% of baseline value (average of 2 best values) and forced mid-expiratory flow (FEF) (25-75) \> 75% of baseline * Total Lung Capacity (TLC) \> 90 % of baseline * Post-transplant chest radiograph without significant abnormality * No evidence of on-going lung infection or allograft rejection Early CLAD patients-inclusion criteria: * FEV1 \< 80% of baseline value (average of 2 best values) * Follow up 6-months or decline in lung function (20% decrease in FEV1 without evidence of infection or acute rejection) Exclusion Criteria: * SAO2 drops below 90% (in absence of mechanical failure) during normal tidal breathing * Unilateral diaphragm paralysis * Evidence of acute illness on day of study * Evidence of restrictive lung disease * Dependence on supplemental oxygen * History of cardiac disease * Pregnancy (self-declared) * Lactating women * Participants with metal objects in their body * Known contraindication to MRI examination * Systolic blood pressure reading of \< 100 mmHg or \> 200 mmHg * Diastolic blood pressure reading of \<60 mmHg or \> 100 mmHg