The aim of the study is to assess the effects of vasoactive agents on the degree of contrast enhancement in experimental atherosclerotic plaque during contrast-enhanced ultrasonography (CEUS). Abdominal aortic atherosclerosis was induced in 25 New Zealand white rabbits by a combination of cholesterol-rich diet and balloon endothelial denudation. Standard ultrasonography and CEUS were performed at baseline and during intravenous infusion of noradrenaline or adenosine triphosphate (ATP). The degree of contrast enhancement of the plaque after injection of contrast material was quantified by calculating the enhanced intensity in the plaque. The infusion of noradrenaline induced significant increase in systolic blood pressure (84 +/- 13 mm Hg vs. 112 +/- 20 mm Hg, p = 0.011) and significant decrease in the enhanced intensity in the plaque (7.52 +/- 1.32 dB vs. 5.88 +/- 1.33 dB, p < 0.001) during CEUS. The infusion of ATP resulted in the significant decrease in systolic blood pressure (80 +/- 13 mm Hg vs. 65 +/- 11 mm Hg, p - 0.005) and increase in the enhanced intensity in the plaque (7.52 +/- 1.32 dB vs. 8.84 +/- 1.55 dB, p < 0.001) during CEUS. The degree of contrast enhancement within an experimental atherosclerotic plaque during CEUS can be influenced by vasoactive agents and hemodynamic status. (C) 2014 World Federation for Ultrasound in Medicine & Biology.