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Session: Vascular III
Session starts: Friday 27 January, 14:00
Presentation starts: 14:45
Room: Room 559

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Judith Pruijssen (Radboudumc)
Stein Fekkes (Radboudumc)
Chris de Korte (Radboudumc)
Rik Hansen (Radboudumc)

Abstract:
Ultrasound is the most used imaging modality to assess vascular health. Carotid intima-media thickness (IMT) and stenosis degree are validated measures of atherosclerotic disease associated with cerebrovascular events at population level. However, they are not sufficiently specific for personalized treatment selection. IMT and stenosis degree are both geometrical measures. They do not provide information on wall composition and mechanics which are considered key parameters of vascular health. Alterations in vascular wall stiffness may proceed vascular wall thickening, and plaque composition correlates better with stroke risk than stenosis degree. New ultrasound techniques, including shear wave elastography (SWE), allow for tissue stiffness assessment. Carotid wall SWE has shown to correlate with cardiovascular risk factors[1]. Furthermore, SWE values seem to differ between symptomatic and asymptomatic and between stable and unstable plaques[2]. This study, therefore, aims to evaluate the applicability of SWE for vascular health assessment. Currently, longitudinal SWE imaging is commercially available. We evaluated this method in twenty-six patients ≥5 years after unilateral irradiation for head and neck neoplasms. We assessed radiation-induced changes in vascular thickness (IMT) and stiffness (SWE) in irradiated compared to unirradiated carotids. Measurements were performed in four segments (proximal/mid/distal common, and internal carotid artery). As patients received unilateral irradiation, the non-irradiated side served as internal control. We found higher IMTs, and a trend towards higher SWVs in some segments in irradiated compared to non-irradiated carotids. However, when applied to carotid plaques, not all plaques can be imaged with longitudinal SWE. Therefore, we developed a cross-sectional SWE-method with steered ultrasound beams to enable shear wave tracking along the entire arterial circumference. In this way, possibly all plaques can be visualized. To evaluate this method, we performed cross-sectional SWE measurements in vessel-mimicking phantoms with a stiff wall and soft plaque. Plaques could be detected, a great part of the wall circumference (~80%) could be visualized, and measurements were highly accurate. Concluding, SWE shows promising results in vascular health assessment. Longitudinal SWE could enable radiation-induced vasculopathy assessment. Furthermore, we developed a method for cross-sectional SWE enabling visualization of plaques located along the entire arterial circumference. We will further evaluate this in vivo. [1] Marais et al. Ultrasound Med Biol, 45(3): 758-772, 2019. [2] Pruijssen, et al., Ultrasound Med Biol, 46(9): 2145-2163, 2020.