Carotid ultrasonography

Carotid ultrasonography is an ultrasound-based diagnostic imaging technique to evaluate structural details of the carotid arteries. Carotid ultrasound is used to diagnose carotid artery stenosis (CAS) and can assess atherosclerotic plaque morphology and characteristics. Carotid duplex and contrast-enhanced ultrasound are two of the most common imaging techniques used to evaluate carotid artery disease. Carotid ultrasound is a low-cost, noninvasive, and accurate diagnostic imaging modality used to evaluate diseases of the carotid arteries. It is most often used to diagnose carotid artery stenosis, a form of atherosclerosis, and has the capability to assess plaque morphology and characteristics. Carotid artery stenosis is a major risk factor for stroke, and risk assessment of atherosclerotic carotid plaques is a critical component of stroke prevention. Advances in imaging have allowed for risk stratification including degree of stenosis and how vulnerable the atherosclerotic plaque is to rupture. Other plaque features that contribute to stroke risk and can be evaluated by imaging are: intraplaque hemorrhage, plaque ulceration and neovascularization, fibrous cap thickness, and presence of a lipid-rich necrotic core (LNRC). Carotid ultrasound is the preferred initial diagnostic test to evaluate carotid artery stenosis, and can also be used to monitor response to lipid-lowering therapy. Digital subtraction angiography (DSA), magnetic resonance angiography (MRA), and CT angiography (CTA) are confirmatory imaging techniques typically employed after ultrasound and prior to therapeutic intervention. DSA is the gold standard for evaluating CAS, and MRI is the gold standard for carotid plaque imaging. Duplex ultrasound (duplex) combines standard B-mode ultrasound and Doppler ultrasonography to evaluate both structural details of the carotid arteries and blood flow through the arteries. During carotid duplex evaluation, the 2D B-mode structural image is superimposed with the doppler flow data, which provides a more realistic anatomical assessment.