[Duplex ultrasound in cerebrovascular disease - asymptomatic carotid stenosis].

Duplex ultrasound in cerebrovascular disease - asymptomatic carotid stenosis Distal embolization originating from an ipsilateral asymptomatic carotid stenosis (ACS) is the cause of a substantial proportion of first-ever ischemic strokes. Duplex ultrasound is recommended as first-line imaging method to detect and to evaluate the extent and severity of such extracranial carotid stenoses. All patients with ACS need best cardiovascular medical therapy including smoking cessation strategies, implementation of statins, antihypertensive drugs and antiplatelet therapy. The annual stroke rate in patients with ACS has significantly declined during the last years due to improvement in medical therapy. Therefore, surgical prophylactic carotid endarterectomy or carotid stenting no longer are recommended routinely in all patients with high-grade ACS. Several studies demonstrated that not only the grade of stenosis based on hemodynamic criteria on Duplex ultrasound increases the ipsilateral stroke risk, but also morphological characteristics on B-mode ultrasound and contrast-enhanced ultrasound are associated with more vulnerable ACS with higher risk of stroke. These additional morphological features may be useful to select a subgroup of patients with ACS who may benefit from interventions. There is some evidence that a high progression rat of the grade of stenosis on duplex ultrasound, hypoechogenicity, higher plaque area, surface irregularities and ulceration on B-mode ultrasound as well as intraplaque vascularization on contrast-enhanced ultrasound of the carotid stenosis are predictors of such a vulnerable ACS. This review article gives an overview of ultrasound based and other features of ACS, which are associated with an increased ipsilateral stroke risk.