A method for diagnosing pulmonary hypertension from phase-contrast magnetic resonance (MR) images includes providing a time series of one or more magnetic resonance (MR) flow images of a patients mediastinum during one or more cardiac cycles, segmenting the pulmonary artery within each image of the times series of images, identifying the anterior wall and pulmonary valve within the segmented pulmonary artery, analyzing blood flow during a diastolic phase of the one or more cardiac cycles to determine a relative duration of blood flow, tstreamlines, during the diastolic phase, analyzing blood flow during a latter portion of a systolic phase and a subsequent diastolic phase of the one or more cardiac cycles to detect the presence and duration tvortex of a vortex, and diagnosing the presence of pulmonary hypertension from tstreamlines and tvortex.