Assessing Response to Inhaled Prostacyclin With Hyperpolarized Xe MRI

Hyperpolarized 129Xenon gas XeMRI scans will provide 3D images of ventilation and gas exchange pre, post, and 2-4 hours post inhaled prostacyclin treatment. Subjects will inhale HP 129Xe from the dose delivery bags with each scan and then move into the scanner and undergo basic 1H localizer and anatomical scans. Once localization is complete, subjects will undergo several MRI scans after inhalation of HPXe. This will occur as three scans at the three different time points (pre, post, and 2-4 hours post) of inhaled prostacyclin treatment.