This article presents an exhaustive review of MRI in the assessment of the pulmonary arteries (sequences, normal results, clinical signs of the main diseases). Its current preferential indications are: the study of the main pulmonary artery trunks (primary tumours, proximal embolism, caliber abnormalities, anatomical relations with central tumours), the assessment and post-treatment follow-up of pulmonary arterial malformations. Angio-MRI is currently being developed and, in the near future, should allow the reliable diagnosis of pulmonary embolism and will therefore be indicated alongside spiral computed tomography. MRI also allows functional assessment of the right circulation (measurements of circulatory velocity and flow rates). It should rapidly become an examination of choice in the haemodynamic follow-up of patient with pulmonary hypertension and transplant recipients and as an evaluation tool for new drugs.