New methods for intraoperative examination of the electrical properties of the brain

• Applicant: Privatdozent Dr. Tammam Abboud
• Subject Area: Clinical Neurology; Neurosurgery and Neuroradiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 560730114

The goal of this project is to enhance the understanding of the electrical properties of brain tissue, particularly white matter and its anisotropy, with the aim of developing a method for intraoperative impedance measurement. This method could potentially be used during brain tumor resections to differentiate between healthy white matter and tumor tissue. Two sequential experiments are planned: I. Electrical impedance measurement of white matter in pig brain and correlation with Diffusion Tensor Imaging: The objective of this experiment is to investigate the electrical anisotropy of white matter and correlate it with the anisotropy measured through imaging techniques. It is well-known that fiber tracts in white matter have different spatial orientations. For example, the fiber tracts in the corpus callosum run horizontally between the two hemispheres (left-right), while those in the internal capsule run in an anterior-posterior direction. The corticospinal tract, in contrast, runs cranio-caudally. In addition, various fiber tracts cross to connect different cortical areas within one hemisphere. Modern Diffusion Tensor Imaging allows for the measurement of fractional anisotropy (FA) in white matter. In this experiment, the electrical impedance will be measured at various locations in the white matter, with the direction of the measurement being varied to calculate electrical anisotropy. In this way, a correlation between the electrically measured anisotropy and the FA measured through imaging can be established. The result will be a map of the electrical impedance and anisotropy of the pig brain. II. Electrical Impedance Tomography of the brain using subdural strip electrodes: The goal of this experiment is to establish the basis for intraoperative imaging through impedance measurement, known as Electrical Impedance Tomography. Here, subdural strip electrodes will serve as current sources and recording electrodes, capturing the resulting voltage changes within the brain. Using the map generated in Experiment I, the processing and interpretation of the collected data will enable the imaging of the structures through which the current flows. The study will examine which intracerebral structures can be visualized through impedance tomography and how the conditions for this can be optimized. The aim is to develop a novel method for intraoperative intracranial imaging, which could be used during brain tumor resections to assess the tumor's location and size intraoperatively. This method would have the advantage of being easy to apply, time-efficient, and non-disruptive to the course of the surgery.

• DFG Programme: Research Grants
• Co-Investigators: Professorin Dr. Susann Boretius; Dr. Günter Hahn