Contrast-enhanced ultrasound imaging of periadventitial vasa vasorum in human carotid arteries

Arterial vasa vasorum (VV) are known to be involved in the atherosclerotic process. The aim of the present study was to explore whether ultrasound imaging with contrast agent is able to visualize adventitial VV in human carotid atherosclerosis. We studied with standard ultrasound 25 patients with carotid stenosis > 50% (ATS group) and 15 patients without carotid artery plaques and an intima-media thickness (IMT) < 1.0 mm (CTRL group). All patients underwent contrast ultrasound to evaluate periadventitial VV and B-flow imaging (BFI) modality was used to improve and measure periadventitial flow signal. On contrast-enhanced images, a fast microbubble flow and a homogeneous and linear periadventitial contrast signal using BFI were detectable in the adventitial area in all patients of both groups. Periadventitial signal thickness by BFI was higher in patients with atherosclerosis than in the control group (mean +/- SD: CTRL 0.80 +/- 0.06 mm; ATS 1.10 +/- 0.11 mm; P < 0.001). Moreover, considering the whole study population, the adventitial signal thickness significantly correlated with IMT values (r= 0.88, r(2)= 0.77; P < 0.0001). Periadventitial contrast signal was detected in all patients and BFI thickness was higher in patient with carotid atherosclerosis and correlated with IMT.