Chapter 4 - Cardiovascular elastography

Abstract

Cardiovascular disease currently claims more lives each year in both men and women than the next two most deadly diseases combined, i.e., cancer and chronic lower respiratory disease. Among the cardiovascular diseases, coronary artery disease (CAD) is by far the deadliest accounting for 44% of cardiovascular-related deaths and causing approximately 1 of every 6 deaths in the United States in 2017. Approximately every 34s, one American has a coronary event, and approximately every 1min 23s, an American will die of one. One of the main reasons for this high death toll is the severe lack of effective and accessible imaging tools upon anomaly detected on the electrocardiogram, especially at the early stages when CAD can be stabilized with appropriate pharmacological regimen. The two most widely used imaging techniques in the clinic are echocardiography, nuclear perfusion, and CT angiography with limitations in reliability, speed of application, ionizing radiation and contrast/stress induction requirements, and cost and invasiveness, respectively. Clinical observations also show that the formation, expansion, and rupture phases of a vessel due to pathologies such as aneurysms and atherosclerotic plaques are each associated with changes in arterial stiffness. Pulse wave velocity (PWV) is often used as a biomarker, but imaging of pulse waves and characterizing the propagation has been essential in staging vascular disease. In this chapter, we introduce ultrasound-based methodologies that provide information on both the mechanical and electrical properties of the myocardium as well as mechanical properties of the vascular wall in order to better image the onset and progression of the aforementioned diseases.