Abstract
The positive relationship among lesion echolucency, degree of stenosis, maximal lesion thickness, and contrast enhancement supports the idea that more advanced atherosclerotic plaques that are likely to rupture have a greater degree of neovascularization.
Purpose
To correlate echogenicity and severity of atherosclerotic carotid artery lesions at standard ultrasonography (US) with the degree of intraplaque neovascularization at contrast material–enhanced (CE) US.
Materials and Methods
This HIPAA-compliant study was approved by the local ethics committee, and all patients provided informed consent. A total of 175 patients (113 [65%] men, 62 [35%] women; mean age, 67 years ± 10 [standard deviation]) underwent standard and CE US of the carotid artery. Lesion echogenicity (class I to IV), degree of stenosis, and maximal lesion thickness were evaluated for each documented atherosclerotic lesion. The degree of intraplaque neovascularization at CE US was categorized as absent (grade 1), moderate (grade 2), or extensive (grade 3). Correlation of neovascularization with echogenicity, degree of stenosis, and maximal lesion thickness was made by using Spearman ρ and χ2 test for trend.
Results
In a total of 293 atherosclerotic lesions, echogenicity was inversely correlated with grade of intraplaque neovascularization (ρ = −0.199, P < .001). More echolucent lesions had a higher degree of neovascularization compared with more echogenic ones (P < .001). The degree of stenosis was significantly correlated with grade of intraplaque neovascularization (ρ = 0.157, P = .003). Lesions with higher degree of stenosis had higher grade of neovascularization (P = .008), and maximal lesion thickness increased with the grade of neovascularization (P < .001) and was significantly correlated with grade of neovascularization (ρ = 0.233, P < .001).
Conclusion
Neovascularization visualized with CE US correlates with lesion severity and with morphologic features of plaque instability, contributing to the concept that more vulnerable plaques are more likely to have a greater degree of neovascularization. Therefore, CE US may be a valuable tool for further risk stratification of echolucent atherosclerotic lesions and carotid artery stenosis of different degrees.
© RSNA, 2011
Supplemental material: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10101008/-/DC1
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Article History
Received May 19, 2010; revision requested July 1; final revision received August 2; accepted August 12; final version accepted August 16.Published online: Feb 2011
Published in print: Feb 2011