Magnetic induction tomography: A feasibility study of brain oedema detection using a finite element human head model

Neurological aggraviations of patients with craniocerebral injury can trace back in most cases to a swelling of the brain. The survey of these patients is carried out with intracranial pressure sensors in combination with different imaging techniques. This method causes a big distress for the patients, thus new non-invasive methods are required. One promising possibility is magnetic induction tomography, a non-invasive and contactless imagine method for reconstructing the electrical tissue properties in the region of interest. This technique is attractive for the detection of brain oedema, because the magnetic field penetrates easily through the skull and due to the increased fluid accumulation an oedema represents a more or less localized perturbation of the conductivity within a normal brain. We carried out a feasibility study with a 3D arrangement, which comprises a human brain model, an array of 16 excitation coils and 32 receiving coils. The human brain model consists of about 35000 tetrahedral finite elements and considers the cerebrospinal fluid around the brain, the grey matter, the white matter and a spherical oedema. The inverse problem is solved by means of a single step algorithm with four regularization methods and the results show the possibility of the detection of pathological hydration changes with good localization.