Implications of the Kinematic Activity of the Atherosclerotic Plaque: Analysis Using a Comprehensive Framework for B-Mode Ultrasound of the Carotid Artery

The fact that carotid atherosclerosis is the most common cause of stroke, coupled with the exceptionally high levels of mortality, morbidity, and disability for stroke events, places a valid risk stratification for the disease among the major public health challenges. The unique features of ultrasound imaging have established it as the cornerstone in the diagnosis and monitoring of carotid atherosclerosis, while ultrasound has also demonstrated a substantial potential in providing novel, automated, risk markers, valuable in the diagnosis, evaluation, and treatment selection for the disease. This chapter aims to leverage the use of kinematic analysis from B-mode ultrasound toward a better understanding of the mechanical phenomena taking place in atherosclerotic carotid arteries, recognizing the vulnerable carotid plaque, and studying potential different kinematic phenotypes of the disease. To this end, we first present a comprehensive framework for quantifying the kinematic activity of the arterial wall from B-mode ultrasound images of the carotid artery in terms of spatiotemporal indices and spatiotemporal patterns. We then apply this framework to retrospectively collected data of patients with carotid atherosclerosis, and we show that: (a) motion analysis from ultrasound imaging is able to effectively quantify bilateral asymmetries in the carotid artery which may arise by differences in mechanical and anatomical characteristics, (b) both spatiotemporal indices and spatiotemporal patterns have substantial capacity in discriminating symptomatic from asymptomatic patients with carotid atherosclerosis, and (c) motion analysis may prove valuable in elucidating different imaging phenotypes of the disease associated with the extent (size) of the atherosclerotic plaque.