Contrast-Enhanced Ultrasound for the Evaluation of Neovascularization in Atherosclerotic Carotid Artery Plaques

Abstract

ResultsWe enrolled 60 consecutive patients and excluded 10 because of severe calcification and large ulcers (Table). The contrast Background and Purpose-Neovascularization associated with plaque vulnerability, particularly in the plaque shoulder, is susceptible to rupture, causing ischemic events. We aimed to use contrast-enhanced ultrasound to evaluate neovessels in carotid plaques quantitatively, focusing on plaque shoulders. Methods-Using contrast-enhanced ultrasound with perflubutane, we analyzed 50 consecutive patients who underwent carotid endarterectomy. We measured enhanced intensity and assessed the correlation between contrast effect and histopathology, comparing symptomatic and asymptomatic plaques. Results-Enhanced intensity of the plaque shoulder was associated with neovessel density (P<0.01; ρ=0.43). Enhanced intensity of the plaque shoulder was higher in plaques with rupture than in those without (P<0.05), and in symptomatic plaques (n=31) than in asymptomatic ones (n=19; P<0.01). Conclusions-Quantitative evaluation of the contrast effect using contrast-enhanced ultrasound enabled the assessment of neovascularization of plaque shoulders in vivo real time, which may help stratify plaque vulnerability. of plaque shoulders was greater than that of cores (EI S versus EI C , 9.6±3.6 versus 1.1±1.6 dB, respectively; P<0.0001), consistent with histological findings that cores contained lipid and hemorrhage with few neovessels, mainly localized in plaque shoulders ( Figure 2). EI S associated with neovessel density in the plaque shoulder (P=0.0017; ρ=0.43; Figure I in the onlineonly Data Supplement). EI S was higher in plaques with rupture than in those without rupture (EI S , 10.1±3.5 versus 6.9±3.2 dB, respectively; P=0.018). EI S tended to be higher in plaques with intraplaque hemorrhage than in those without rupture (EI S , 9.9±3.6 versus 7.6±2.5 dB, respectively; P=0.095).The contrast effect of the plaque shoulder of symptomatic plaques was significantly greater than that of asymptomatic plaques (EI S , 10.8±3.7 versus 7.7±2.4 dB, respectively; P=0.0016). Among symptomatic plaques, EI S values of plaques that had a time interval from the onset of the last event to carotid endarterectomy of ≤6 months were higher than those of plaques with an interval of >6 months, but the difference was not statistically significant (EI S , 11.3±3.7 versus 9.2±3.7 dB, respectively; P=0.34; Figure II in the online-only Data Supplement). DiscussionThe histological characteristics of vulnerable plaques, including intraplaque hemorrhage, thrombus, inflammatory cells, thin fibrous caps, and neovascularization, were reviewed.2 Neovessels are immature and fragile, particularly in plaque shoulders, because local inflammatory damage and shear stress from the arterial lumen lead to collapse, causing intraplaque hemorrhage and plaque rupture, 1 consistent with the present results. Although MRI 3 and computed tomographic angiography 4 using contrast agents yield highly reproducible evaluations of carotid artery neovascularization...

Identification of neovascularization by contrast–enhanced ultrasound to detect unstable carotid stenosis

“…So far, only few studies by us and others have directly compared CEUS and histopathology [2,18,23]. In this investigation, focal enhancements of contrast corresponded well to intraplaque neovascularization (Figs 1 and 4).…”

Inverse association between size of the lipid‐rich necrotic core and vascularization in human carotid plaques

“…The proposed mechanism for plaque vascularization to increase the vulnerability of the plaque is by increasing the risk of IPH (Hellings et al, 2010). This is supported by a recent study using CEUS showing that vascularization of symptomatic plaques seems to be locally increased in the shoulder regions (Saito et al, 2014). This is supported by a recent study using CEUS showing that vascularization of symptomatic plaques seems to be locally increased in the shoulder regions (Saito et al, 2014).…”

Use of Contrast-enhanced Carotid Ultrasonography in Preoperative Assessment for Carotid Artery Stenting

“…CEUS has recently been used to visualize intraplaque neovascularization as an element of vulnerability. 4,[8][9][10][11][12] The source of neovascularization is direct branching from the vasa vasorum or the intimal surface. These areas are very fragile, and plaque hemorrhage can easily occur.…”