Hyper Polarized Xenon-129 MRI vs Xenon-133 Scintigraphy

This study is comparing two types of lung imaging in COPD (chronic obstructive pulmonary disease) patients: a newer MRI technique using inhaled xenon-129 gas versus a traditional nuclear medicine scan using xenon-133, to see which better shows how air moves through the lungs. **You may be eligible if...** - You have a confirmed diagnosis of COPD - You are at your normal, stable health baseline on the day of imaging (not during a flare-up) - You are a current or former smoker with at least a 10 pack-year smoking history - Your COPD severity has been classified according to standard criteria (GOLD classification) **You may NOT be eligible if...** - You have a diagnosis of asthma - You require continuous oxygen at home - Your blood oxygen level is too low - You are currently experiencing a COPD flare-up Talk to your doctor to see if this trial is right for you.