La resonancia magnética en la evaluación de la aterotrombosis, del miocardio isquémico, hibernado o cicatrizado y de la microcirculación

The technique of nuclear magnetic resonance imaging (MRI) is entering a period of great expansion thanks, in part, to the development of new molecular markers that enable extremely sophisticated images to be obtained in real time. Applications range from studying the pathophysiological mechanisms underlying the development of disease to improving diagnosis and evaluating the effects of specific treatments. The technique has the advantage that it is highly sensitive and specific, as well as noninvasive, and can be performed in a relatively short time. The molecular characterization of arterial lesions and the biological processes actively involved in ischemic heart disease, and the identification of new risk factors for atherosclerotic disease progression are some of the new applications currently under development. Using the technique, it is possible to quantify coronary flow reserve at a very high spatial resolution. Additionally, the passage of contrast medium through the myocardium after vasodilator drug administration can be visualized and its transit time quantified, thereby enabling the level of perfusion to be determined in different myocardial segments. In addition to providing useful information on the state of the microvasculature, perfusion, and myocardial contractility, MRI can also be used to determine the amount of necrotic tissue, and to identify myocardium that is viable but clearly dysfunctional (e.g., hibernating or stunned). Moreover, there is a broad spectrum of other applications that is just beginning to be explored with this imaging technology and that has a promising future; one example is monitoring the biodistribution of autologous cells used in myocardial regeneration therapy. There is no doubt that MRI will soon become fundamental to the study of cardiovascular disease, to its diagnosis and prognosis, and to monitoring treatment responses.