Clinical Doppler ultrasound for the assessment of plaque ulceration in the stenosed carotid bifurcation by detection of distal turbulence intensity: a matched model study

Abstract

The assessment of flow disturbances due to carotid plaque ulceration may provide added diagnostic information to Doppler ultrasound (DUS) of the carotid stenosis, and indicate whether the associated hemodynamics are a potential thromboembolic source. We evaluated the effect of ulceration in a moderately stenosed carotid bifurcation on distal turbulence intensity (TI) measured using clinical DUS in matched anthropomorphic models. Several physiologically relevant ulcer geometries (hemispherical, mushroom-shaped, and ellipsoidal pointing distally and proximally) and sizes (2-mm, 3-mm and 4-mm diameter hemispheres) were investigated. An offline analysis was performed to determine several velocity-based parameters from ensemble-averaged spectral data, including TI. Significant elevations in TI were observed in the post-stenotic flow field of the stenosed carotid bifurcation by the inclusion of ulceration (P < 0.001) in a region two common carotid artery diameters distal to the site of ulceration during the systolic peak and the diastolic phase of the cardiac cycle. Both the size and shape of ulceration had a significant effect on TI in the distal region (P < 0.001). Due to the use of a clinical system, this method provides the means to evaluate for plaque ulcerations in patients with carotid atherosclerosis using DUS.

Flow Patterns in Carotid Bifurcation Models Using Pulsed Doppler Ultrasound: Effect of Concentric vs. Eccentric Stenosis on Turbulence and Recirculation

“…Similarly, an eccentrically 50%-stenosed model demonstrated turbulence intensity values # 20 cm/s, which increased to 25-30 cm/s in the presence of various ulcerations (Wong et al 2009). This suggests that for mildly to moderately stenosed vessels, factors such as ulcerations also may be a significant contributor to flow disturbances but stenosis severity becomes a more dominant factor with increasing disease.…”

Evolution of Atherosclerotic Carotid Plaque Morphology: Do Ulcerated Plaques Heal? A Serial Multidetector CT Angiography Study

“…Firstly, plaque ulcerations may induce thrombus formation by disturbing the blood flow. In vitro flow experiments with ultrasound showed that the flow downstream from ulcerated, moderate stenotic, carotid plaques was more disturbed than from nonulcerated plaques [24]. Similarly, an experimental slipstream visualization technique showed that the introduction of an ulceration into a stenotic carotid bifurcation produced observable flow disturbances [4].…”

Comparison of Carotid Plaque Ulcer Detection Using Contrast-Enhanced and Time-of-Flight MRA Techniques

“…30 Flow patterns were visualized by randomly seeding 250,000 tracer particles within and away from the ulcer and tracking their evolution over 3 cardiac cycles, using previously reported techniques.…”