Time-resolved three-dimensional contrast-enhanced magnetic resonance angiography in patients who have undergone a Fontan operation or bidirectional cavopulmonary connection: Initial experience

Purpose: To evaluate the usefulness of time-resolved three-dimensional (3D) magnetic resonance angiography (MRA) using diluted contrast agent (CA) in patients who had undergone a Fontan operation or bidirectional cavopulmonary connection (BCPC). Materials and Methods: Time-resolved 3D MRA (10 dynamic data sets, two seconds per dynamic data set) using parallel imaging and keyhole data sampling was performed on 15 patients (median age = 10 years, range = 1-20 years) who had undergone a Fontan operation (N = 11) or BCPC (N = 4). Diluted gadolinium (Gd) contrast agent (CA) was intravenously injected into the arm and/or leg veins. The flow dynamics and morphology of pulmonary circulation, and lung perfusion were assessed. Results: Preferential or balanced pulmonary blood flow from each systemic vein was visualized on time-resolved 3D MRA in all patients. In addition, occlusion/stenosis of the 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, and axillary arteriovenous fistula were delineated in three patients, respectively. Conclusion: Time-resolved 3D MRA with diluted CA is useful for evaluating patients who have undergone a Fontan operation or BCPC because it can reveal the flow dynamics and morphology of pulmonary circulation, and lung perfusion status.