Legend. Enhancement of carotid plaque by contrast echo. Panel A shows 3 consecutive frames of contrast ultrasound imaging of an atherosclerotic carotid bulb lesion with contrast microbubbles within the plaque. Panel B shows a micrograph of a carotid hemorrhagic fibrocalcific plaque. In the area of a thin fibrous cap (inset, panel C) numerous CD31/CD34 positive neovessels are present. A large first-order vasa vasorum (*) with a thin vessel wall surrounded by small second-order vasa (arrows, ×10) is present. See page 228.