This work sought to identify a non-invasive means to detect pulmonary arterial hypertension (PAH). 129Xenon MRI and dynamic spectroscopy were acquired in healthy volunteers and subjects with chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), left heart failure (LHF), and PAH. COPD was differentiated from PAH by increased ventilation and barrier defects, while IPF was differentiated by increased barrier uptake. PAH and LHF subjects had similar imaging features but could be differentiated by their RBC signal oscillation amplitudes. 129Xe MR imaging and spectroscopy appears capable of differentiating PAH from COPD, IPF, and LHF.