Estimation of the thermal effect of blood flow in a branching countercurrent network using a three-dimensional vascular model.

A three-dimensional thermal model is presented in which convective heat transfer is defined in terms of the physical details of the vascular system. The convective heat exchange between prearteriole and postvenule vessels and the tissue across the vessel walls is calculated explicitly without using shape factors. Conduction in x-, y-, and z-direction is considered. This vascular model is applied to a human extremity. The spatial variations in the arterial, venous and tissue temperatures under basal conditions, hyperthermic conditions and in a cold environment are computed. Conclusions are drawn as to the validity of bioheat approaches.