Indication: screening for extracranial vascular disease primarily at the carotid bifurcation
Strengths:
Noninvasive
Safe
No ionizing radiation
Weaknesses:
Operator dependent; can be significantly influenced by skills and bias of operator
Of limited utility for disease above the region of the carotid bifurcation
In 10% of patients, carotid bifurcation lies above angle of jaw, making ultrasound difficult or impossible
Subject to errors of interpretation in cases of high-grade stenoses or complete occlusion
Calcified plaques interfere with visualization of vascular lumen
Difficulty visualizing tandem lesions
Echolucency of acute thrombi (indistinguishable from flowing blood)
Comments:
Carotid arteriography is necessary when surgical intervention is contemplated.
Duplex color flow Doppler is the best initial screening test to evaluate the carotid arteries.