| Popis: |
The concept of the unstable, so-called "high risk" or vulnerable atheromatous plaque has been accepted for several years and its biological, mechanical and cellular features (collagen top, lipid core with macrophages, metalloproteinases...) have been determined. However, the means of investigating these lesions remain limited. A description of their composition has become essential as the prognosis of coronary, aortic and carotid artery disease is no longer evaluated only by morphometric data (degree of stenosis). MRI with T1 or T2 contrast sequences, density of spin, chemical shift, diffusion, magnetisation transfer or spectroscopy provides a non-invasive tool for their study. This method, based on the detection of magnetic atomic nuclei (such as proton H1, carbon 13, sodium 23, potassium 49) enables tissue characterisation by means of the variations in chemical environment and their consequences on the degree of magnetisation of the nuclei studied. High frequency ultrasound could also be used to this end by measuring the coefficients of attenuation and back-scattering. These methods, used clinically and in different animal models, should improve our understanding of the physiopathology, facilitate diagnosis and improve the prognostic accuracy in patients with atherosclerosis. |
