Visualization of Temperature and Heat Transfer in Human Brain based on Magnetic Resonance

Abstract

Heat transfer rate(HTR) is one of the critical issues in controlling the brain tissue temperature under laser irradiation for tumor ablation. To map heat transfer rate in the brain, in this research, cerebral blood flow (CBF) maps were obtained using tissue residue curves of dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) with gadolinium (Gd) contrast agent. Once CBF maps were obtained the heat transfer rate of the tissue was mapped at various tissue temperature. The DSC-MRI measurements were performed for patients with glioblastoma ($\mathrm{N}\ =\ 2$), meningioma ($\mathrm{N}=2$). The perfusion rates in the brain normal parenchyma obtained from CBF maps for the subjects agreed well with the values shown in the database. In the glioblastoma cases, CBF values in the tumor region was relatively low and diffused compared with those in the meningioma cases, in which rich vascular beds are contained in the tumor. The HTR maps were then calculated for 40 to 45 °C for all the subjects. The resultant maps clearly showed the degree of HTR in the unit of watt per cubic meter. From the maps, it was suggested that the heating effect is higher in glioblastoma than in meningioma, and that the HTR data here may be applicable to simulate the temperature distribution in the tissue based on the bio-heat transfer equation.