[Magnetic resonance in the characterization of atherosclerotic lesions].

Fifty-one patients with occlusive and dilating vascular diseases were evaluated with MR imaging, using T1 and T2-weighted sequences and an 0.5 T superconducting magnet. Atheromatous plaques were detected in the carotids and on the aortic walls. Fatty lesions had high signal intensity on T1-weighted sequences and could be well distinguished from older thrombotic depositions which presented with medium signal intensity on T1-weighted scans and low signal on T2-weighted images. Thrombotic depositions in aneurysmal dilatation of the aorta and carotid arteries could be distinguished from patent internal lumen; inside them, areas of different signal intensity were demonstrated, which were related to the paramagnetic effect of hemoglobin degradation products (hemosiderin and methemoglobin).