Atherosclerotic carotid bifurcation phantoms with a stenotic soft inclusion for flow-structure ultrasound imaging analysis

As the complexity of ultrasound signal processing algorithms increases, it becomes more difficult to demonstrate their added value. In the context of quantitative measurements such as vascular elastography, vector flow mapping, and ultrafast tissue Doppler, innovative validation strategies are required. Phantoms have been widely used but they do not correspond to the geometry of vulnerable carotid atherosclerotic plaques containing a large lipid pool embedded within the vessel wall of an anthropomorphic lumen geometry.We propose a method of manufacturing such phantoms for applications in flow imaging and elastography. The internal carotid geometry was based on a computed tomography scan of a healthy individual. During the fabrication process, a soft inclusion mimicking a stenotic lipid pool was embedded within the vascular wall. The phantom wall and soft inclusion were made of polyvinyl alcohol (PVA) that undergone different numbers of freezing-thawing cycles to produce different mechanical property.Mechanical testing measured Young's moduli of the vascular wall and soft inclusion at 342 ± 25 kPa and 17 ± 3 kPa, respectively. Strain elastography results on the lipid pool mimicking inclusion, fibrous cap and remaining phantom wall showed greater strain in the lipid pool, which is consistent with expected results. Because of their realistic geometries and mechanical properties, those phantoms may become advantageous for fluid-structure experimental studies and validation of new ultrasound-based imaging technologies.