Analytical heat transfer model for targeted brain hypothermia

• We derive an analytical solution to heat transfer of brain hypothermia.
• The theoretical model is validated by reported experimental data.
• Blood temperature supplied to brain affects core zone temperature significantly.
• Surface cooling temperature has little impact on the core temperature.

This paper reports an analytic solution to the heat transfer in targeted brain hypothermia. This study simplifies brain as a two-layer structure consisting of scalp and brain matter and uses Pennes bioheat equation to describe the thermal process in the brain. We derived an analytical solution for temperature distribution using the method of Laplace transform. The solution is validated by a published rat experiment. Our study reveals that temperature distribution in the brain can be divided into two zones: a superficial zone and a core zone. The outside-scalp temperature significantly affects the temperature distribution in the superficial zone, but the temperature has little influence on the temperature in the core zone. In contrast, arterial blood perfusion can significantly affect the temperature of the core zone. Decreasing arterial blood temperature will cause a drastic decline in the core zone temperature, leading to a large decrease in the temperature gradient between the core zone and the head surface. Our theoretical results support that controlling the blood perfusion and temperature into the brain is the efficient approach to brain hypothermia.