Lipid-rich carotid artery plaques appear echolucent on ultrasound B-mode images and may be associated with intraplaque haemorrhage

Objective: To relate the histological composition of carotid artery plagues with morphology as evaluated by B-mode ultrasound. Design: Prospective study. Material and Methods: Seventy-eight symptomatic patients underwent carotid endarterectomy after preoperative ultrasound Duplex scanning evaluating plague morphology. Morphometric analysis of the removed specimen was performed in order to quantity content of lipid, haemorrhage, calcification and fibrous tissue. Results: Echolucent plagues contained more lipid (p=0.01) and less calcification (p=0.01) and fibrous tissue (p=0.03) than echo-rich plagues. Intraplaque haemorrhage was directly related to lipid content (p=0.004) and inversely related to amount of fibrous tissue in the plague (p=0.02); Conclusion: The intensity of the reflected B-mode ultrasound signal appears related to the histological composition of the plague. The association between intraplaque haemorrhage and a high lipid content may support the theory of the lipid-rich plague being more prone to rupture.