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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

Plaque neovascularization and intra-plaque hemorrhages.(A) Hematoxylin/eosin staining of carotid plaque reveals intraplaque vessels densely filled with erythrocytes (red arrows) alongside acute intraplaque hemorrhages (blue arrows). (B) Higher magnification demonstrates extravascular erythrocytes indicative of intraplaque hemorrhages (black arrow). The intraplaque hemorrhages shown here must be relatively fresh because individual erythrocytes are still clearly demarcated. (C) Axial imaging of carotid artery by contrast-enhanced ultrasound (CEUS). The red arrow points to the area that corresponds to the histological image (A). CEUS is not able to distinguish between contrast agent located within neovessels and contrast agent moving freely within the plaque, such as may be the case in neovessel rupture followed by intraplaque hemorrhage.
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pone.0175331.g005: Plaque neovascularization and intra-plaque hemorrhages.(A) Hematoxylin/eosin staining of carotid plaque reveals intraplaque vessels densely filled with erythrocytes (red arrows) alongside acute intraplaque hemorrhages (blue arrows). (B) Higher magnification demonstrates extravascular erythrocytes indicative of intraplaque hemorrhages (black arrow). The intraplaque hemorrhages shown here must be relatively fresh because individual erythrocytes are still clearly demarcated. (C) Axial imaging of carotid artery by contrast-enhanced ultrasound (CEUS). The red arrow points to the area that corresponds to the histological image (A). CEUS is not able to distinguish between contrast agent located within neovessels and contrast agent moving freely within the plaque, such as may be the case in neovessel rupture followed by intraplaque hemorrhage.

Mentions: Moreover, histological evaluation of regions with intense and prolonged intraplaque enhancement regularly yielded neovascularization and acute intraplaque hemorrhage (Fig 5). CEUS is not able to distinguish between contrast agent located within neovessels and contrast agent moving freely within the plaque, such as may be the case in acute neovessel rupture and subsequent intraplaque hemorrhage.


Identification of neovascularization by contrast – enhanced ultrasound to detect unstable carotid stenosis
Plaque neovascularization and intra-plaque hemorrhages.(A) Hematoxylin/eosin staining of carotid plaque reveals intraplaque vessels densely filled with erythrocytes (red arrows) alongside acute intraplaque hemorrhages (blue arrows). (B) Higher magnification demonstrates extravascular erythrocytes indicative of intraplaque hemorrhages (black arrow). The intraplaque hemorrhages shown here must be relatively fresh because individual erythrocytes are still clearly demarcated. (C) Axial imaging of carotid artery by contrast-enhanced ultrasound (CEUS). The red arrow points to the area that corresponds to the histological image (A). CEUS is not able to distinguish between contrast agent located within neovessels and contrast agent moving freely within the plaque, such as may be the case in neovessel rupture followed by intraplaque hemorrhage.
© Copyright Policy
Related In: Results  -  Collection

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

pone.0175331.g005: Plaque neovascularization and intra-plaque hemorrhages.(A) Hematoxylin/eosin staining of carotid plaque reveals intraplaque vessels densely filled with erythrocytes (red arrows) alongside acute intraplaque hemorrhages (blue arrows). (B) Higher magnification demonstrates extravascular erythrocytes indicative of intraplaque hemorrhages (black arrow). The intraplaque hemorrhages shown here must be relatively fresh because individual erythrocytes are still clearly demarcated. (C) Axial imaging of carotid artery by contrast-enhanced ultrasound (CEUS). The red arrow points to the area that corresponds to the histological image (A). CEUS is not able to distinguish between contrast agent located within neovessels and contrast agent moving freely within the plaque, such as may be the case in neovessel rupture followed by intraplaque hemorrhage.
Mentions: Moreover, histological evaluation of regions with intense and prolonged intraplaque enhancement regularly yielded neovascularization and acute intraplaque hemorrhage (Fig 5). CEUS is not able to distinguish between contrast agent located within neovessels and contrast agent moving freely within the plaque, such as may be the case in acute neovessel rupture and subsequent intraplaque hemorrhage.

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