Magnetic resonance imaging of mediastinal vessels.

Advances in technology have led to a changing role for MRI in the evaluation of the thoracic vasculature in children. MRI, especially with 3D gadolinium-enhanced MR angiography, can clearly demonstrate the morphology of the aortic and pulmonary vascular supply. In patients with nonvalvar obstructive lesions of the aorta (i.e., coarctation, interruption of the aortic arch, and supravalvar stenosis), MRI can reliably assess the site and extent of the obstruction. Similarly, MRI can depict the morphology of the central pulmonary arteries and aortopulmonary collateral vessels in patients with obstructive lesions of the pulmonary artery. MRI is also useful in assessing the course of the aorta and pulmonary arteries in patients with suspected vascular rings. The result is that MRI can supplement information obtained from echocardiography and angiography and reduce the need for angiography.