MSc assignment: Modeling of oxygen distribution in the human brain

MSc assignment
Modeling of oxygen distribution in the human brain

In the LT-Biomagnetism group (Bennie ten Haken)

We are looking for a student that is interested in modeling and in the physiology of the human brain. We will ask of you to make a model to predict the oxygen distribution in the human brain, using available data from measurements of blood vessel networks in the cerebral cortex. With this model the different layers of the human cortex can be examined.

Background
We are currently investigating new techniques and methods for earlier and easier detection and treatment of ischemia (lack of oxygen) in the human brain, using EEG, MEG and/or MRI.

The human brain depends critically on the supply of energy in the form of oxygen and sugars. These are supplied from fresh blood flowing into the microvessels in the brain tissue, from where they diffuse into the tissue. When the oxygen content of the blood is too low, parts of the tissue farther away from the blood vessels can no longer be supplied with sufficient oxygen. This will cause changes in the electrical behavior of the affected neurons, which can perhaps be used for diagnosing patients. To be able to predict these changes, knowledge about the distribution of oxygen concentrations is needed.

For a single straight blood vessel in a cylinder of oxygen consuming tissue, analytical expressions can be derived for the oxygen concentrations in the tissue. However, for the oxygen distributions in a realistic geometry of blood vessels, either a clever analytical approximation has to be found, or numerical computations have to be done (finite element models or Green function approaches for example). The basis of these computations is solving the Poisson (diffusion/heat) equation, but they also have to take into account the blood flow, the (non-linear) oxygen storage in red blood cells and the oxygen consumption of the tissue.

Contact:
Bas-Jan Zandt, room CR 3619 (b.zandt@utwente.nl)

Figure 1: Finite difference computation of oxygen pressures around a single capillary. The rectangle denotes the position of the vessel, filled with a single file of red blood cells.

Figure 2: SEM scan technique visualizing microvessels of chinchilla auditory cortex.

(Harrison et al. 2002)