M.Sc. Yannik Lutz

Rosa Daschner

In western countries, stroke is the third-most widespread cause of death. 80% of all strokes are ischemic and caused by a cerebral thrombosis or an embolism. The mortality rate of ischemic strokes is about 25%, while 35–55% of affected patients experience permanent disability. Therapeutic hypothermia (TH) showed neuroprotective effect and can possibly decrease the stroke induced cerebral damage. Recently, an intracarotid cooling sheath was developed to induce local TH in the penumbra using the cooling effect of cranial blood flow via collaterals. Unfortunately, so far the control and regulation of the temporal and spatial cerebral temperature course is connected to invasive temperature measurements. Computational modeling provides unique opportunities to predict the resulting temperature decrease of the brain tissue and could replace the invasive procedure.
The aim of this work is the generation of a simplified brain model to establish a cerebral temperature calculation using Penne’s Bio-Heat-Equation and an existing cerebral hemodynamics model. In this context, an extensive literature research will be performed and the terminal segments of the hemodynamics model will be assigned to corresponding perfused brain tissue. Therefore, the model’s terminal segments will be adapted and the auto regulation will be updated. In the second part of this work, a basic brain geometry will be generated. For the temperature simulation needed perfusion rates will be derived from the terminal flow rates of the hemodynamics model.
The temperature calculation will be performed in COMSOL® using the Bio-Heat-exchange package. In multiple simulations the resulting spatial brain temperatures will be calculated in case of an ischemic stroke varying the performances of the cooling sheath and the cerebral collataralization degree.