Detection of Atherosclerosis Through Mapping Skin Temperature Variation Caused by Carotid Atherosclerosis Plaques

Abstract

This paper reports the effects of atherosclerosis plaque on the human cervicum skin surface temperature. The classical Pennes bioheat equation and a 3-D model consisting of cervical vertebra, muscle, and skin layer is adopted to characterize the heat transfer in the cervicum. Since the formation of atherosclerotic plaque is random, several parametric analyses are conducted to simulate actual situations. A medical far-infrared thermal imaging system is employed on two healthy human subjects to evaluate the feasibility of this technique. According to the simulations, there are variations in the temperature contours on the surface of the skin due to the axial variations in thermal parameters between healthy arterial intimae and atherosclerosis plaque. This suggests that far-infrared thermal imaging can be used to detect the marker safely via a noncontact way. Additional parametric studies indicated that the cervicum skin surface temperature distribution discloses the information regarding the plaque such as position, depth, pattern, quantity, and metabolic heat generation, etc. Furthermore, the external thermal conditions and calm physiological state can be implemented to enhance the detection of the plaque via mapping skin temperature. To test this strategy, a far-infrared imaging system was applied to record the dynamic thermal pictures on the cervicum of two human subjects, and the intentional cooling by the alcohol was proposed to improve detection. The thermograph reveals the surface effects of the main blood vessel and organs in the cervicum. The present study sets up a theoretical foundation for using noncontact far-infrared imaging method for a reliable assessment of atherosclerosis plaque without causing any wound or radiation to human body.