Atherosclerosis of carotid and intracranial arteries

The role of diagnostic imaging in the study of atherosclerosis of carotid and intracranial vessels is analyzed, after the illustration of the main characteristics of the disease. Atherosclerosis should be considered a systemic disease, however it tends to be segmental. The commonest sites are the coronary artery, the superficial femoral artery, the subrenal aorta and the carotid arteries at the level of the bifurcation. Traditionally, the percentage of intraluminal stenosis has represented the standard measurement of the severity of atheromatosis. However, the grade of stenosis is not the only sign predictive of clinical complications. The most vulnerable plaques show predominant core necrosis or hemorrhage, separated from the vascular lumen by a thin unstable fibrous cap. The two major aspects of lesions at high risk of rupture are the presence of a large soft core and the status of the fibrous cap that can be intact, ruptured or infiltrated by inflammatory cells. Imaging procedures should be addressed to the identification of these pathologic conditions predisposing to the embolic-thrombotic complication. However, additional information on blood flow dynamics, vascular collateral compensation and brain perfusion is useful for decision-making about the therapeutic approach. This is the reason why in diagnostic imaging of atheromatosis, digital angiography should be combined with color Doppler-US, CT and MRI.