Use of Hyperpolarized 129Xe MR Lung Imaging in Infants

All Cohorts Inclusion Criteria: * Male or female * Any age NICU inpatient who is clinically stable and with adequate temperature control to tolerate MRI as determined by the primary clinical team Cohort 1 * Age 0 - 6 months * NICU patient on oxygen with a nasal cannula (≤ 2L per minute) (unchanged - supplemental O2 for minimum 24 hours) * Maintaining SpO2 \> 88% on nasal O2 Cohort 2 * Age 0 - 6 months * NICU patient who requires a slightly higher level of respiratory support (with High Flow Nasal Cannula \> 2L per minute, CPAP, or RAM cannula and O2 unchanged for minimum 24 hours), with FiO2 \< 50%. * Maintaining SpO2 \> 88% on nasal O2 Exclusion Criteria: * General anesthesia within 24 hours prior to MRI or other sedation (e.g. morphine, Versed, fentanyl) within the last 4 hours. * Extracorporeal membrane oxygenation (ECMO) support * Evidence of any respiratory infection within 1 week of testing (imaging may be rescheduled for a common viral infection such as a cold). * Suspected muscular dystrophy or neurologic disorder that may affect lung development. * Significant genetic or chromosomal abnormalities that may affect lung development * Congenital heart disease * Uncontrolled atrial or ventricular arrhythmia * Open surgical wounds * Need for inotropic support * Need for vasodilator agents * Need for high level of respiratory support (i.e. FiO2 \>50%, and/or higher respiratory support than listed in Cohort 2 Inclusion Criteria, such as invasive ventilation). * Standard MRI exclusion criteria as set forth by the CCHMC Department of Radiology (e.g., contraindicated support/implant equipment that is not MR compatible). * Infant size not compatible with NICU MRI scanner (\~\>4.5kg).