Measurement of Blood Perfusion Using the Temperature Response to Constant Surface Flux Heating

A closed-form analytical solution of the Pennes bio-heat equation was developed for the temperature distribution in skin tissue subjected to a constant surface heat flux. Elevations in the surface temperature were revealed to be related to blood perfusion rates and heating fluxes based on which a new noninvasive approach has been developed to determine the blood perfusion rates. Sensitivities of the temperature elevation to blood perfusion and heating flux were investigated, as was the influence of thermal contact resistance on the perfusion estimate. It has been demonstrated that this influence is relatively small and can be effectively eliminated by application of highly conductive grease. An experimental system for this method was developed, and the blood perfusion rates in various human locations, including forearm, thigh, and calf, were measured using the system. The blood perfusion rate of skin tissue is in the range of 4 to 6 kg · s−1 ·m−3, which is in good agreement with those reported in the literature.