Hyper Polarized Xenon-129 MRI vs Xenon-133 Scintigraphy

Who May Qualify: - Subjects must have a diagnosis of COPD - at their clinical baseline on the day of imaging - must be clinically stable in order to participate in the study. - COPD subjects will be categorized according to the GOLD - Current/Former SmokerSubjects - must have a smoking history ≥ 10 pack years Who Should NOT Join This Trial: - Dx of asthma - Continuous oxygen use at home - Blood oxygen saturation of 92% less than as measured by pulse oximetry on the day of imaging - FEV1 percent predicted less than 25% - Pregnancy or lactation - Claustrophobia, inner ear implants, aneurysm or other surgical clips, metal foreign bodies in eye, pacemaker or other contraindication to MR scanning - Subjects with any implanted device that cannot be verified as MRI compliant will be excluded - Chest circumference greater than that of the xenon MR and/or helium coil. The circumference of the coil is approximately 42 inches - History of congenital cardiac disease, chronic renal failure, or cirrhosis - Inability to understand simple instructions or to hold still for approximately 10 seconds - History of respiratory infection within 2 weeks prior to the MR scan - History of MI, stroke and/or poorly controlled hypertension. Always talk to your doctor about whether this trial is right for you.