紐⑹�� : To evaluate the usefulness of time-resolved 3D magnetic resonance angiography (MRA) using diluted contrast agent in patients with Fontan operation or bidirectional cavopulmonary connection (BCPC). 諛⑸�� : In 15 patients (median age =10 years, range 1 year – 20 years) who underwent Fontan operation (n = 11) or BCPC (n = 4), time-resolved 3D MRA (10 dynamics, 2 seconds/dynamic) using parallel imaging and keyhole data sampling was performed. Diluted gadolinium contrast agent was intravenously injected through arm and/or leg veins. Flow dynamics and morphology of pulmonary circulation, and lung perfusion were assessed. 寃곌낵 : Preferential or balanced pulmonary blood flow from each systemic vein could be visualized on time-resolved 3D MRA in all patients. In addition, occlusion/stenosis of central thoracic vein (n = 4) and pulmonary artery (n = 6), systemic venous (n = 5) and arterial (n = 6) collaterals, and lung perfusion defect (n = 4) were identified. Persistent hepatic venous plexus, pulmonary arteriovenous malformation, or axillary arteriovenous fistula was delineated each in one patient. 寃곕�� : Time-resolved 3D MRA using diluted contrast agent is useful in evaluating patients with Fontan operation or BCPC by providing flow dynamics and morphology of pulmonary circulation, and lung perfusion status.