Ultraschall Med 2015; 36(02): 154-161
DOI: 10.1055/s-0034-1366410
Original Article
© Georg Thieme Verlag KG Stuttgart · New York

Quantitative Contrast-Enhanced Ultrasound of Intraplaque Neovascularization in Patients with Carotid Atherosclerosis

Quantitativer kontrastverstärkter Ultraschall der Neovaskularisation von artherosklerotischen Plaques der Karotis
S. C. H. van den Oord
1   Cardiology, Erasmus Medical Center, Rotterdam, Netherlands
,
Z. Akkus
2   Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands
,
J. G. Bosch
2   Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands
,
A. Hoogi
3   Biomedical Engineering, Israel Institute of Technology, Haifa, Israel
,
G. L. ten Kate
4   Internal Medicine, Erasmus Medical Center, Rotterdam, Netherlands
,
G. Renaud
2   Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands
,
E. J. G. Sijbrands
4   Internal Medicine, Erasmus Medical Center, Rotterdam, Netherlands
,
H. J. Verhagen
5   Vascular Surgery, Erasmus Medical Center, Rotterdam, Netherlands
,
A. van der Lugt
6   Radiology, Erasmus Medical Center, Rotterdam, Netherlands
,
D. Adam
3   Biomedical Engineering, Israel Institute of Technology, Haifa, Israel
,
N. de Jong
2   Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands
,
A. F. W. van der Steen
2   Biomedical Engineering, Erasmus Medical Center, Rotterdam, Netherlands
,
A. F. L. Schinkel
1   Cardiology, Erasmus Medical Center, Rotterdam, Netherlands
› Author Affiliations
Further Information

Publication History

13 September 2013

11 February 2014

Publication Date:
13 May 2014 (online)

Abstract

Purpose: Intraplaque neovascularization (IPN) is an increasingly studied marker of the vulnerable atherosclerotic plaque, and contrast-enhanced ultrasound (CEUS) is an in vivo imaging technique for the assessment of IPN. The purpose of this study was to test novel quantification methods for the detection of carotid IPN using CEUS.

Materials and Methods: 25 patients with established carotid atherosclerosis underwent bilateral carotid CEUS using a Philips iU-22 ultrasound system with an L9 – 3 transducer. Visual scoring of IPN was performed using a 3-point score. Quantification of IPN was performed using novel custom developed software. In short, regions of interest were drawn over the atherosclerotic plaques. After motion compensation, several IPN features were calculated. Statistical analysis was performed using Spearman’s rho. Reproducibility of the quantification features was calculated using intra-class correlation coefficients and mean differences between calculations.

Results: 45 carotid arteries were available for the quantification of IPN. The quantification of IPN was feasible in all 45 carotid plaques. The IPN area, IPN area ratio and neovessel count had a good correlation with the visual IPN score (respectively ρ = 0.719, ρ = 0.538, ρ = 0.474 all p < 0.01). The intra-observer and inter-observer agreement was good to excellent (p < 0.01). The intra-observer and inter-observer variability was low.

Conclusion: The quantification of carotid IPN on CEUS is feasible and provides multiple features on carotid IPN. Accurate quantitative assessment of IPN may be important to recognize and to monitor changes during therapy in vulnerable atherosclerotic plaques.

Zusammenfassung

Ziel: Die Intraplaque-Neovaskularisation (IPN) ist ein in zunehmendem Maße untersuchter Parameter bei einer vulnerablen artherosklerotischen Plaque und der kontrastverstärkte Ultraschall (CEUS) dient als bildgebendes Verfahren für die in-vivo-Bewertung der Karotis-IPN. Das Studienziel bestand in der Austestung neuer Quantifizierungsmethoden beim Nachweis einer Karotis-IPN mittels CEUS.

Material und Methoden: An 25 Patienten mit bestätigter Atherosklerose der Halsschlagader wurde ein bilateraler Karotis-CEUS mit dem Philips iU-22 Ultraschallsystem und einem L9–3-Schallkopf durchgeführt. Die visuelle IPN-Bewertung wurde mit einer 3-Punkte-Skala durchgeführt. Die Quantifizierung der IPN erfolgte mit einer neuartigen, maßgeschneiderten kundenspezifischen Software. In Kürze zusammengefasst wurden „Regions of Interest“ über die artherosklerotischen Plaques gezogen. Nach der Bewegungskompensation wurden verschiedene IPN-Parameter berechnet. Die statistische Analyse erfolgte mit dem Spearmans-Rangkorrelationskoeffizienten. Die Reproduzierbarkeit der Quantifikationsparameter wurde durch Intraklasse-Korrelationskoeffizienten und durch die mittleren Differenzen zwischen den Kalkulationen errechnet.

Ergebnisse: Für die Quantifizierung der IPN standen 45 Halsschlagadern zur Verfügung. Die IPN-Quanifizierung war in allen 45 Karotisplaques durchführbar. Die Übereinstimmung der visuellen IPN-Bewertung mit der IPN-Fläche (ρ = 0,719), der IPN-Flächen-Ratio (ρ = 0,538) und der Anzahl der Neugefäße (ρ = 0,474) war gut (jeweils p < 0,01). Die Intraobserver- und Interobserver-Übereinstimmung war gut bis ausgezeichnet (p < 0,01). Die Intraobserver- und Interobserver-Variabilität war niedrig.

Schlussfolgerung: CEUS ermöglicht die quantitative Analyse von Karotis-IPNs und bestimmt mehrere Merkmale der Neovaskularisation von artherosklerotischen Karotis-Plaques. Eine präzise quantitative Analyse der IPN kann therapiebegleitend für die Erkennung und die Überwachung von Veränderungen vulnerabler artherosklerotischer Plaques von Bedeutung sein.

 
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