A Doppler Flow Analysis of the Neovascular Flow in Carotid Plaque Using Ultrasound Micro-flow Imaging

Carotid artery stenting (CAS) was recommended for the treatment of severe carotid artery stenosis. One problem associated with CAS is cerebral infarction due to embolic events. Vulnerable plaque with bleeding and neovascularization is a risk factor for such events. Bleeding in plaque has been evaluated by ultrasonography and MRI. However, detection of neovascularization in plaque has not been established. We measured the intraplaque microcirculatory blood flow of 6 patients who underwent CAS with superb micro-vascular imaging (SMI). We compared the SMI signal and the embolic events following CAS. Case 3 had an SMI-positive signal with clear Doppler flow in the affected plaque; he subsequently showed plaque protrusion and asymptomatic embolic events. Another patient showed no Doppler signal. Doppler flow detected by SMI was found to be related to neovascularity of plaque. This finding might indicate the plaque vulnerability.