Hyper Polarized Xenon-129 MRI vs Xenon-133 Scintigraphy

Inclusion Criteria:

* 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

Exclusion Criteria:

* 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.