Pulmonary arterial distensibility - 2D phase contrast vs 2D bSSFP

Background The pulmonary circulation is a highly compliant system that generates little resistance to blood flow. However, in the presence of pulmonary arterial hypertension (PAH), blood pressure and vascular resistance in the pulmonary circulation are elevated. This leads to distension and stiffening of the main pulmonary artery (MPA) and vessel wall remodeling, which in itself may influence stiffness [1]. Proximal arterial distensibility is a parameter that depends mainly on the anatomy (geometry) of the vessel and can be estimated noninvasively with cross-sectional imaging techniques. In particular, the relative area change (RAC) of the MPA, which is inversely proportional to arterial stiffness, is a strong predictor of mortality in patients with PAH [2]. The purpose of this study was to compare two non-invasive magnetic resonance imaging (MRI) methods for quantification of MPA distensibility using an acute PAH dog model.