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

View Article: PubMed Central - PubMed

ABSTRACT

Background: Plaque neovascularization accompanies local inflammation and critically contributes to plaque instability. Correct identification of intraplaque neovascularization by contrast–enhanced ultrasound (CEUS) may provide an additional risk marker in carotid stenosis. This pilot study investigates the correlation between histological evaluation of carotid plaque specimens and pre-surgery CEUS to identify neovascularization.

Methods: 17 patients with high-grade internal carotid artery (ICA) stenosis were studied. CEUS was performed in all patients shortly before carotid endarterectomy. Neovascularization, infiltration of T cells and macrophages along with intraplaque hemorrhage were studied in excised plaques by immunohistochemistry. Ultrasound-based four-level and two-level classification systems for neovascularization were used. CEUS findings were compared with histological findings.

Results: Scores on the CEUS-based four-level and two-level classifications were robustly correlated with the density of intraplaque vessels (r = 0.635, p = 0.006 and r = 0.578, p = 0.015, respectively). Histological evaluation of regions with strong and prolonged intraplaque enhancement typically showed strong intraplaque neovascularization in conjunction with acute intraplaque hemorrhage. Moreover, higher grades of intraplaque neovascularization as determined by ultrasound were associated with a higher percentage of macrophage-rich areas.

Conclusion: CEUS is a technique well suited to gauge the degree of neovascularization of carotid plaques. Future research will have to define the reliability and validity of CEUS in everyday clinical practice. Further, our study suggests that CEUS may also be useful to pick up features of vulnerable plaques such as acute intraplaque hemorrhages.

No MeSH data available.


Related in: MedlinePlus

Contrast–enhanced ultrasound (CEUS) for assessing neo-vascularization of carotid plaque.(A) Color Doppler ultrasound of carotid bifurcation. The dotted area represents the stenotic carotid plaque. CCA: Common carotid artery. ICA: Internal carotid artery. ECA: External carotid artery. (B) CEUS of the same area as shown in A. Note yellow-orange color of the contrast agent filling the lumen of the carotid artery. Furthermore, CEUS contrast effects are visible within the carotid plaque (yellow square), indicating plaque neovascularization. (C) Immunohistological evaluation of the plaque area shown in B with anti-CD31 antibody staining. The arrows mark CD31-positive neovessels.
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pone.0175331.g001: Contrast–enhanced ultrasound (CEUS) for assessing neo-vascularization of carotid plaque.(A) Color Doppler ultrasound of carotid bifurcation. The dotted area represents the stenotic carotid plaque. CCA: Common carotid artery. ICA: Internal carotid artery. ECA: External carotid artery. (B) CEUS of the same area as shown in A. Note yellow-orange color of the contrast agent filling the lumen of the carotid artery. Furthermore, CEUS contrast effects are visible within the carotid plaque (yellow square), indicating plaque neovascularization. (C) Immunohistological evaluation of the plaque area shown in B with anti-CD31 antibody staining. The arrows mark CD31-positive neovessels.

Mentions: A typical false-color Doppler ultrasound scan of the carotid bifurcation is given in Fig 1. Important anatomical landmarks including the carotid plaque are highlighted. A freeze-frame shot from a CEUS video clip (S1 Video) of the same patient is provided in Fig 1. The flow dynamics of contrast agent within the vessel and plaque are illustrated. Fig 1 then allows the direct comparison of CEUS findings with the histological evaluation (CD31 vessel staining) of the identical area within the carotid plaque of the same patient.


Identification of neovascularization by contrast – enhanced ultrasound to detect unstable carotid stenosis
Contrast–enhanced ultrasound (CEUS) for assessing neo-vascularization of carotid plaque.(A) Color Doppler ultrasound of carotid bifurcation. The dotted area represents the stenotic carotid plaque. CCA: Common carotid artery. ICA: Internal carotid artery. ECA: External carotid artery. (B) CEUS of the same area as shown in A. Note yellow-orange color of the contrast agent filling the lumen of the carotid artery. Furthermore, CEUS contrast effects are visible within the carotid plaque (yellow square), indicating plaque neovascularization. (C) Immunohistological evaluation of the plaque area shown in B with anti-CD31 antibody staining. The arrows mark CD31-positive neovessels.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5384678&req=5

pone.0175331.g001: Contrast–enhanced ultrasound (CEUS) for assessing neo-vascularization of carotid plaque.(A) Color Doppler ultrasound of carotid bifurcation. The dotted area represents the stenotic carotid plaque. CCA: Common carotid artery. ICA: Internal carotid artery. ECA: External carotid artery. (B) CEUS of the same area as shown in A. Note yellow-orange color of the contrast agent filling the lumen of the carotid artery. Furthermore, CEUS contrast effects are visible within the carotid plaque (yellow square), indicating plaque neovascularization. (C) Immunohistological evaluation of the plaque area shown in B with anti-CD31 antibody staining. The arrows mark CD31-positive neovessels.
Mentions: A typical false-color Doppler ultrasound scan of the carotid bifurcation is given in Fig 1. Important anatomical landmarks including the carotid plaque are highlighted. A freeze-frame shot from a CEUS video clip (S1 Video) of the same patient is provided in Fig 1. The flow dynamics of contrast agent within the vessel and plaque are illustrated. Fig 1 then allows the direct comparison of CEUS findings with the histological evaluation (CD31 vessel staining) of the identical area within the carotid plaque of the same patient.

View Article: PubMed Central - PubMed

ABSTRACT

Background: Plaque neovascularization accompanies local inflammation and critically contributes to plaque instability. Correct identification of intraplaque neovascularization by contrast–enhanced ultrasound (CEUS) may provide an additional risk marker in carotid stenosis. This pilot study investigates the correlation between histological evaluation of carotid plaque specimens and pre-surgery CEUS to identify neovascularization.

Methods: 17 patients with high-grade internal carotid artery (ICA) stenosis were studied. CEUS was performed in all patients shortly before carotid endarterectomy. Neovascularization, infiltration of T cells and macrophages along with intraplaque hemorrhage were studied in excised plaques by immunohistochemistry. Ultrasound-based four-level and two-level classification systems for neovascularization were used. CEUS findings were compared with histological findings.

Results: Scores on the CEUS-based four-level and two-level classifications were robustly correlated with the density of intraplaque vessels (r = 0.635, p = 0.006 and r = 0.578, p = 0.015, respectively). Histological evaluation of regions with strong and prolonged intraplaque enhancement typically showed strong intraplaque neovascularization in conjunction with acute intraplaque hemorrhage. Moreover, higher grades of intraplaque neovascularization as determined by ultrasound were associated with a higher percentage of macrophage-rich areas.

Conclusion: CEUS is a technique well suited to gauge the degree of neovascularization of carotid plaques. Future research will have to define the reliability and validity of CEUS in everyday clinical practice. Further, our study suggests that CEUS may also be useful to pick up features of vulnerable plaques such as acute intraplaque hemorrhages.

No MeSH data available.


Related in: MedlinePlus