Breathing in a special gas reveals hidden lung damage in transplant patients

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

General Inclusion Criteria: * For transplant recipients: the subject is a lung transplant recipient who is over 18 years of age, underwent lung transplantation at the Hospital of the University of Pennsylvania or Temple University Hospital, and is receiving follow up care from the Penn or Temple Lung Transplantation teams following said transplant. Written informed consent will be obtained and documented after the subject receives oral and written information about the study. * For diagnosed CLAD patients: the subject is a lung transplant recipient who is over 18 years of age, underwent lung transplantation at the Hospital of the University of Pennsylvania or Temple University Hospital, and has recently received a clinical diagnosis of CLAD. Written informed consent will be obtained and documented after the subject receives oral and written information about the study. * For non-transplant COPD patients: the subject is over 18 years old, has been diagnosed with chronic obstructive pulmonary disease, and has never received a lung transplant. * For healthy controls: the subject is over 18 years of age. Exclusion Criteria: * Patients less than 18 years old * Patients known to be pregnant - a positive pregnancy test will be used to respectively exclude pregnant patients, * Any known contraindication to MRI examination * Anyone with an implanted metal device * Inability to provide informed consent * A language, communication, cognitive or behavioral impairment that might interfere with fully informed participation in the study. * History of uncompensated organ failure (i.e. organ failure that is not stabilized through medical intervention), which will be assessed by the PI. * Homelessness or other unstable living situation * Active drug or alcohol dependence * Claustrophobia * Subjects weighting more than 300 pounds. * Subjects with chest size larger than the bore of MRI machine from the study