Nichtinvasive Charakterisierung der Arteriosklerose mittels Magnetresonanz

Atherosclerosis and its thrombotic complications are the major cause of morbidity and mortality in the industrialised countries. Despite advances in our understanding of the pathogenetic mechanisms and new treatment modalities, the absence of adequate non-invasive methods for early detection limits prevention or treatment of patients with atherothrombotic disease. The ideal clinical imaging modality for atherosclerosis should be safe, inexpensive, non-invasive or minimally invasive, accurate and reproducible, thus allowing longitudinal studies in the same patients. Additionally, the results should reflect the extent of atherosclerotic disease and have a high predictive value for clinical events. In vivo, high-resolution magnetic resonance imaging (MRI) has recently emerged as one of the most promising techniques for the non-invasive assessment study of atherothrombotic disease in several vascular beds such as the aorta, the carotid arteries and the coronary arteries. Most importantly MRI can be used to characterise plaque composition as it allows the discrimination of lipid core, fibrosis, calcification, and intra-plaque haemorrhage deposits. MRI findings have been extensively validated against pathology in ex vivo studies of carotid, aortic, and coronary artery specimens obtained at autopsy and using experimental models of atherosclerosis. In vivo, MRI of carotid arteries of patients referred for endarterectomy has shown a high correlation with pathology and with previous ex vivo results. A recent study in patients with plaques in the thoracic aorta showed that, compared with transoesophageal echocardiography, plaque composition and size are more accurately characterised and measured using in vivo MRI. Of note, the composition rather than the degree of stenosis determines patient outcome. Therefore, a reliable noninvasive imaging tool allowing to detect early atherosclerotic disease in various vascular beds and plaque composition is clinically desirable. MRI has great potential in the detection of arterial thrombi and in the definition of thrombus age. MRI has been used to monitor plaque progression and regression in several animal model of atherosclerosis and in humans. Thus, MRI opens new strategies ranging from screening of high-risk patients for early detection and treatment as well as monitoring the target areas for pharmacological interventions.