Distensibility of the Atherosclerotic Carotid Artery: Relationship With Plaque Burden and Composition?

Arterial distensibility is a marker that can measure vessel wall functional and structural changes resulting from atherosclerosis [5] with applications including estimation of mechanical properties of the wall for biomechanical models. Although arterial segments affected by atherosclerosis are characterized by marked stiffening [2], little is known about the relationship between local specific atherosclerotic plaque features and wall stiffness. In particular, calcification has been shown to be associated with greater wall stiffness, however, this relationship is not consistent in different arterial segments [1,6]. For the carotid arteries, a more thorough understanding of the role of plaque features in determining wall stiffness might be offered by magnetic resonance imaging (MRI). Multi-contrast, high resolution MRI is an established imaging tool to quantify the components of carotid lesions, as well as plaque burden [8,9]. In addition, CINE MRI has been proven to be a reliable tool to measure arterial distensibility [3], an index frequently used to measure stiffness. In this study, our goals were to use MRI to characterize subject-specific wall stiffness in vivo in atherosclerotic carotid arteries, and to analyze the relation between stiffness and plaque burden and composition. CINE MRI was used to measure vessel wall stiffness; whereas a multi-contrast MRI protocol was applied to characterize vessel wall morphology and composition.