Fig 5. Plaque neovascularization and intra-plaque hemorrhages.

(A) Hematoxylin/eosin staining of carotid plaque reveals intraplaque vessels densely filled with erythrocytes (red arrows) alongside acute intraplaque hemorrhages (blue arrows). (B) Higher magnification demonstrates extravascular erythrocytes indicative of intraplaque hemorrhages (black arrow). The intraplaque hemorrhages shown here must be relatively fresh because individual erythrocytes are still clearly demarcated. (C) Axial imaging of carotid artery by contrast-enhanced ultrasound (CEUS). The red arrow points to the area that corresponds to the histological image (A). CEUS is not able to distinguish between contrast agent located within neovessels and contrast agent moving freely within the plaque, such as may be the case in neovessel rupture followed by intraplaque hemorrhage.