Focus on the "unstable" carotid plaque: detection of intraplaque angiogenesis with contrast ultrasound. Present state and future perspectives.

Over the past 20 years, conventional ultrasonography has identified features of the "unstable" carotid plaque. Histological studies have recognized that plaque inflammation and neoangiogenesis play a pivotal role in the developing of the vulnerable plaque. Hence, the growing interest on the biological activities of atherosclerotic lesions leading to cerebrovascular events. The presence of adventitial vasa vasorum and the occurrence of plaque vascularization have been considered as predictors of unstable lesions in cerebrovascular and/or cardiovascular patients. The advent of ultrasound contrast agents has represented a fundamental step in the up-to-date functional evaluation in several fields with minimally invasive procedures. Contrast specific ultrasound modalities are currently used with excellent results in oncology, in cardiology and in vascular diseases. Contrast carotid ultrasound is an emerging imaging technique, able to depict in vivo new functional information on plaque activity and vascularization that may add further new data on the actual condition and future cerebrovascular risk. Further studies will provide a better clarification of the degree of neo-angiogenesis. A future strategy could be represented by the monitoring of plaque neoangiogenesis in order to detect the possible pharmacological effects on plaque remodeling.