Objectives: The goal of this study was to validate right ventricular (RV) elastnace estimated by phase contrast cardiovascular magnetic resonance (PC-CMR) imaging and compare it to clinical outcome in patients with pulmonary arterial hypertension (PAH). Background: Ventricular elastance has been applied to evaluate left ventricular (LV) function. Previous study demonstrated LV outflow tract systolic acceleration (LVOTACC : peak aortic flow velocity/time to peak velocity) derived by Doppler echocardiography was linearly related to the LV elastance. However, its use in evaluating RV function was limited because RV outflow parameters could not be reliably estimated using Doppler echocardiography. Recent investigations showed RV outflow parameters measured by PC-CMR are more accurate and compatible to those by right heart catheterization (RHC). Methods and Results: 30 PAH patients (30% male, 45짹14 years, 50% idiopathic), underwent CMR, TTE, RHC, and 6 minute walk test (6MWT). PC-CMR derived RV outflow tract systolic acceleration (RVOTACC : peak pulmonary flow velocity/time to peak velocity) were compared with parameters acquired by Doppler echocardiography and RHC. RVOTACC by Doppler echocardiography was not correlated with RV elastance by RHC but RVOTACC by PC-CMR showed strong linear correlation compared to RV elastance determined by RHC (r=0.99, p<0.001). In addition, CMR derived Pulmonary Artery Distensibility was positive correlated with 6 MWT (r=0.51, p<001). Conclusions: RV elastance can be noninvasively determined from PC-CMR derived parameters. The proposed index of PC-CMR imaging might be a promising method to predict RV hemodynamics in patients with PAH.