Determination of atherosclerotic plaque temperature in large arteries

Atherosclerotic plaques with high probability of rupture can be characterized by the presence of a hot spot in the arterial wall, which forms due to accumulation of inflammatory cells in the plaque. This paper presents calculations of the arterial wall temperature distribution of arteries affected by plaque. This analysis characterizes the factors affecting plaque temperature, such as vessel geometry, plaque size, inflammatory cell density and distribution, and blood flow pattern. Three vessel types which present high occurrence of plaque are studied: a stenotic straight artery, an arterial bend and an arterial bifurcation corresponding to a human aorta, a coronary artery and a carotid bifurcation, respectively. The atherosclerotic plaque is located in the sites of low shear stress, and a local heat generation is introduced to account for the presence of inflamed plaque.It is shown that the plaque temperature correlates positively to inflammatory cell density and layer thickness, whereas the plaque temperature varies inversely with the depth of the inflammatory cell layer or fibrous cap. From the calculations, it is observed that the best spot to measure plaque temperature is between the middle and the far edge of the plaque where maximum temperature is located. The results contribute to understanding the physical characteristics of the plaque structure and its relationships to plaque temperature, and also suggest a tool to understand the arterial wall temperature measurements obtained with novel catheters.