An analytic and numerical study of intravascular thermography of vulnerable plaque.

Intravascular thermography has been proposed as a method for detecting vulnerable plaque. A marker of vulnerability in a plaque is inflammation, which is believed to reduce its mechanical stability. It has been hypothesized that this inflammation leads to a higher metabolic rate and therefore higher heat generation, causing increased temperature in the vicinity of the plaque. This temperature increase could be measured intravascularly using a temperature sensor, e.g., a thermistor or a thermocouple. The aim of this study is to present a thorough mathematical and physical analysis of the thermal distribution that can be expected in the plaque under various physiological conditions. To get reasonable predictions on the expected temperature distributions, idealized models with simple geometries are solved analytically. More realistic models, with more complex geometries, are solved numerically using the finite element method (FEM). Based on this analysis, the maximum temperature increase that can be expected in a plaque due to increased metabolism is less than 0.1 K.