Identifying vulnerable carotid plaques by noninvasive imaging

Stroke results in considerable morbidity and mortality. Prevention is therefore of particular importance. On the basis of large clinical trials, carotid endarterectomy (CEA) is performed in selected patient groups to prevent stroke. Patient symptomatology and degree of carotid stenosis are the main clinical grounds to perform CEA. However, many individual patients undergo surgery with its attendant risks without taking advantage of it, whereas in others CEA is probably incorrectly withheld. There is therefore an urgent need for new adjuncts to identify high-risk subgroups of patients who particularly benefit from potentially hazardous interventions. Multiple noninvasive imaging modalities have shown their potential to differentiate high-risk, vulnerable carotid plaques from stable plaques. The ultimate goal is to implement one or a combination of these imaging modalities in daily clinical practice. This review gives an up-to-date overview of the clinical potential of these imaging modalities in identifying patients with carotid atherosclerosis who are at high risk for developing stroke. Advantages and limitations of each imaging technique are outlined. Additionally, recommendations for future research are presented. GLOSSARY: CEA = carotid endarterectomy; CCA = common carotid artery; GSM = gray-scale medium; ICA = internal carotid artery; IJV = internal jugular vein; MDCT = multidetector-row CT; MES = microembolic signal; RR = relative risk; TCD = transcranial Doppler; TFE = turbo field echo; TSE = turbo spin echo; USPIO = ultrasmall particles of iron oxide.