Imaging biomarkers for carotid artery atherosclerosis

Abstract

Cardiovascular diseases (CVD) are the leading cause of death in the western world and their prevalence is rising. Currently CVD account for approximately one out of every five lives (Roger et al., 2011). The primary cause of CVD is atherosclerosis, a disease of the vessel wall.

In Figure 1.1 the structure of an arterial vessel is shown schematically. Looking outwards from the center of the vessel it consists of the following parts: • lumen - this is the central area of the vessel where the blood flows through • tunica intima - this layer is composed of a thin sheet of endothelial cells surrounded by a thin elastic layer • tunica media - this is a layer of smooth muscle cells • tunica adventitia - also called tunica externa. This is the outside part of the artery which is made up of an elastic sheet surrounded by collagen

Atherosclerosis causes thickening of the vesselwall due to the accumulation of fatty materials such as cholesterol between the tunica intima and the tunica media. These areas with fatty materials are called plaques. If the vessel wall thickens, the lumen area may get narrower (stenosis) and the blood flow through the vessel may become compromised. Eventually this thickening of the wall can lead to a total occlusion of the vessel. Stenosis of the artery affects the blood and oxygen supply to the distal organs. In the case of the carotid artery, which is the vessel studied in this thesis, this is the brain. Decreased blood supply to the brain can have fatal consequences.