D. Russell
Oslo University Hospital, Department of Neurology – Oslo, Norway

Several non-invasive imaging modalities have shown their potential to identify unstable carotid artery plaques. Echolucent plaques are thought to be more unstable than echo-rich plaques. Images can be evaluated either visually or by computer-assisted gray-scale median (GSM) measurements. Visual evaluation of plaque echogenicity has only fair reproducibility, whereas objective characterization is more reliable and less observer dependent. Plaque irregularity on ultrasound has also been reported to be a risk factor for stroke in general but not for ipsilateral stroke alone.

Symptomatic patients with microembolic signals (MES), assessed by TCD, have been shown to be at high risk for developing ipsilateral stroke. Whether MES positive asymptomatic patients also are at increased risk has not been clarified. The use of ultrasound contrast agents may be helpful in determining plaque surface and plaque neovascularization.