Association between carotid plaque enhancement shown by multidetector CT angiography and histologically validated microvessel density

Abstract

Carotid plaques analysed by MDCTA can show contrast enhancement. The purpose of this study was to explore the association between carotid plaque enhancement (CPE) and microvessel density. We obtained IRB approval. Twenty-nine consecutive (male, 20; median age, 63) symptomatic patients studied with 16-detector CT were prospectively analysed. Examinations were performed before and after intravenous contrast medium administration, and analysis of plaque enhancement was performed. Patients underwent "en bloc" carotid endarterectomy; histological sections were prepared and the presence of microvessels quantified. Logistic regression analysis as well as ROC curve and area under the curve was calculated. A statistically significant association between the degree of CPE and microvessel density (P = 0.009; rho = 0.553) was observed. The ROC curve analysis confirmed this association with an area under the curve of 0.906, 0.735, 0.644 and 0.546 for CPE of 10 HU, 15 HU, 20 HU and 25 HU respectively. There was a statistically significant difference between the CPE and the degree of neovascularisation (P = 0.0003). Results of this preliminary study suggest that CPE might be associated with the microvessel density. Histological analysis seems to demonstrate that the degree of intra-plaque neo-vascularisation is statistically associated with CPE. Carotid artery plaque enhancement at CT is associated with microvessel density. The degree of intra-plaque neo-vascularisation is statistically associated with carotid plaque enhancement. Plaque enhancement at CT should be considered when assessing vulnerable plaques.