Contrast-enhanced ultrasound imaging of intraplaque neovascularization in carotid arteries: correlation with histology and plaque echogenicity.
OBJECTIVE
This study was designed to evaluate contrast-enhanced ultrasound imaging of carotid atherosclerosis as a clinical tool to study intraplaque neovascularization.


BACKGROUND
Plaque neovascularization is associated with plaque vulnerability and symptomatic disease; therefore, imaging of neovascularization in carotid atherosclerosis may represent a useful tool for clinical risk stratification and monitoring the efficacy of antiatherosclerotic therapies.


METHODS
Thirty-two patients with 52 carotid plaques were studied by standard and contrast-enhanced ultrasound imaging. In 17 of these patients who underwent endarterectomy, the surgical specimen was available for histological determination of microvessel density by CD31/CD34 double staining. Plaque echogenicity and degree of stenosis at standard ultrasound imaging were evaluated for each lesion. Contrast-agent enhancement within the plaque was categorized as absent/peripheral (grade 1) and extensive/internal (grade 2).


RESULTS
In the surgical subgroup, plaques with higher contrast-agent enhancement showed a greater neovascularization at histology (grade 2 vs. grade 1 contrast-agent enhancement: median vasa vasorum density: 3.24/mm(2) vs. 1.82/mm(2), respectively, p = 0.005). In the whole series of 52 lesions, echolucent plaques showed a higher degree of contrast-agent enhancement (p < 0.001). Stenosis degree was not associated with neovascularization at histology or with the grade of contrast-agent enhancement.


CONCLUSIONS
Carotid plaque contrast-agent enhancement with sonographic agents correlates with histological density of neovessels and is associated with plaque echolucency, a well-accepted marker of high risk lesions, but it is unrelated to the degree of stenosis. Contrast-enhanced carotid ultrasound imaging may provide valuable information for plaque risk stratification and for assessing the response to antiatherosclerotic therapies, beyond that provided by standard ultrasound imaging.
Coli
Stefano
S
Department of Cardiothoracic and Vascular Diseases, University Vita-Salute, San Raffaele Scientific Institute, Milan, Italy. coli.stefano@hsr.it
Magnoni
Marco
M
Sangiorgi
Giuseppe
G
Marrocco-Trischitta
Massimiliano M
MM
Melisurgo
Giulio
G
Mauriello
Alessandro
A
Spagnoli
Luigi
L
Chiesa
Roberto
R
Cianflone
Domenico
D
Maseri
Attilio
A
D000368:Aged; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D003287:Contrast Media; D004691:Endarterectomy; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging* / Q000601:surgery; D018570:Risk Assessment; D014463:Ultrasonography
D003287:Contrast Media