[Contribution of magnetic resonance imaging to the exploration of the mediastinum].

Magnetic resonance imaging (MRI) already has a number of indications in exploration of the mediastinum, the most frequent of which being exploration of vascular pathologies facilitated by visualization of vascular lumina without need for a contrast medium, MRI can provide detailed information concerning the size, relations and wall thickness of these vessels ans sometimes of aneurysmal thrombosis. It also makes it possible to study aortic dissections and venous diseases of the mediastinum. As regards mediastinal masses, MRI complements computerized tomography (CT): it is better than the latter to distinguish vascular relations and it provides aetiological arguments based on the intensity of T1 and T2-weighted signals.