Temperature Prediction For Selective Brain Hypothermia Based On 3D-Reconstruction Brain Model

The temperature inside brain is vital for the selection of both cooling strategy and time window for brain hypothermia. However, currently, the non-invasive measurement of temperature inside brain is still a challenge, needing further development. Beside this, the simplified hemisphere brain thermal model seems beyond the prediction of the brain temperature.With the aid of Mimics, Geomagic and UG software, medical scanned image data could be used to reconstruct 3D human brain structural model issued four layers of brain, scalp, skull, CSF and brain tissue. Combining with the Pennes’Equation and clinical statistical thermal parameters, the 3D-reconstruction brain thermal model could be used to predict the temperature inside brain. In the simulation, a 70mm-long temperature measuring line beneath the region of the left frontal was selected as the Coordinate values, and furthermore, a series of micro tetrahedrons was produced as analysis element. Thus, a finite elements analysis (FEA) based on the 3D-reconstruction brain thermal model, was performed to simulate the process of thermal conduction and prediction of the temperature distribution inside the brain. In the simulation, three scalp temperatures,0℃,10℃ and 20℃ were preset and the possible thermal conduction process and temperature characteristics inside brain was predicted through the brain thermal model. The characteristics of steady-state and dynamic temperature variations in the temperature measuring line and temperature measuring points was analyzed particularly; meanwhile, the influence of human head structure on the brain thermal model was studied by the comparison of the characteristics of steady-state and dynamic temperature with and without CSF, indicating the importance of the CSF.To study the influence of blood flow and metabolism in the brain on selective brain hypothermia, furthermore, to testify the feasibility of 3D-reconstruction brain thermal model on the prediction of brain temperature, a selective brain hypothermia experiment was established and performed on the rats. Positions 3mm and 5mm beneath the rat skull were set as the measuring points for the brain temperature; a temperature of 20℃ was set to be the scalp temperature. Meanwhile, a rat head thermal model was established through the way developed above, by using of the medical scan data of brain, and the clinical statistical thermal parameters of human. The results displayed that the experimental findings and simulation were not well matched, indicating that accurate thermal parameters of brain besides 3D-structure, are important factors in hypothermia therapy. After parameter identification of blood perfusion rate and metabolic rate of rat, the target FEA was performed. The results from the model explained that the characteristics of steady-state and dynamic temperature well match with the findings from the animal experiments, indicating the feasibility of 3D-reconstruction brain thermal model and identified thermal parameters on predicting brain temperature.