Introduction
Dynamic contrast enhanced ultrasound (DCE-US) is an emerging technology to assess
neovascularization in atherosclerosis. The aim of this study was to quantify a pseudo-enhancement
phenomenon observed during DCE-US of the carotid in other studies.
Methods
Ethical approval was obtained for this prospective case series and each patient gave
written informed consent. 31 patients with 50–99% internal carotid artery stenosis
underwent DCE-US imaging of the carotid bifurcation using 2 ml of intravenous SonoVue™. In the final 10 patients, a further 1 ml bolus was administered after 15 minutes.
Raw linear DICOM data was analysed offline. Regions of interest were drawn within
the common carotid lumen and immediately adjacent in the near and far wall adventitia.
Peak intensity was measured. In addition, an in vitro experiment, using a single channel
flow phantom was performed. SonoVue™ concentrations of 0.02, 0.1, 0.5, 1, and 2 ‰ were pumped into the tube. Regions of
interest were drawn in a similar fashion and the peak intensity measured.
Results
The carotid far wall was significantly more echogenic than the near wall at 2 ml (p < 0.0001,
n = 31) and the far wall intensity rose synchronously with that of the lumen. The
intensity difference was a factor of 4 at 1 ml and 12 at 2 ml. In vitro, the phantom
demonstrated a similar pattern and magnitude of enhancement in an area without vasa
vasorum.
Conclusion
A dose-dependent, non-linear propagation artefact occurs in the far wall adventitia
of the carotid artery, which should not be mistaken as a marker of plaque vulnerability.
