Background:
The ulcerated atheroma of the carotid artery is a risk factor of ipsilateral ischemic stroke. Contrast-enhanced ultrasound (CEUS) is a novel noninvasive technique useful for evaluating the morphology of carotid plaques, and can detect small disruptions on plaque surface. However, it remains unclear whether the disrupted carotid plaque detected by CEUS is related to the symptomatic internal carotid artery stenosis (ICS).
Methods:
A total of 79 ICS patients who underwent carotid endarterectomy (CEA) were enrolled from July 2010 to July 2015. Before operation, ICA lesions were examined by color Doppler ultrasound (CDUS) and CEUS using perflubutane. The ulceration was diagnosed when both of the color Doppler signal on CDUS and the pooling of microbubbles on CEUS were observed within the plaque. The disruption was diagnosed only by CEUS when microbubbles pooled through the fissured surface, unlike the linear delineation of neovessels. We validated findings on ultrasound compared with the histopathological findings of ulceration and present/recent plaque rupture. The associations between ulceration/disruption on ultrasound and symptomatic ICS (with a history of ipsilateral transient ischemic attack and/or ischemic stroke) were investigated.
Results:
Of 79 subjects (mean age 71.2±6.8 years old, 78 men), 55 had symptomatic ICS. The ulceration by CEUS and CDUS was recognized in 20 patients (25%), and the disruption on plaque surface was seen by CEUS solitary in 26 patients (33%). The sensitivity and specificity of detecting plaque ulceration or disruption using CEUS compared with histopathological findings were 0.57 (45/66) and 1.00 (13/13), respectively. The detection rate of ulceration or disruption using CEUS was higher in symptomatic ICS than in asymptomatic ICS (66% vs 42%, P=0.049). Compared to plaques without ulceration/disruption on ultrasound, prevalence of symptomatic ICS was higher in plaques with the disruption (88% vs 58%, P=0.01), whereas it was similar in plaques with the ulceration (65% vs 58%, P=0.77)
Conclusion:
Small disruptions on carotid plaque surface detected by CEUS were significantly related to symptomatic ICS and this results may help the detailed assessment of plaque vulnerability.