Optimisation of current injection protocol based on a region of interest

Area of Science:

• Biomedical Engineering
• Neuroimaging
• Electrical Engineering

Background:

• Electrical impedance tomography (EIT) shows promise for imaging rapid neural activity in the brain.
• Challenges include small voltage changes (<1%) and non-uniform electrode distribution.
• Prior knowledge of activity location is often available, necessitating targeted current injection.

Purpose of the Study:

• To develop and evaluate electrode addressing protocols for EIT that maximize sensitivity to specific brain regions.
• To compare novel protocols with existing methods for improved neural activity imaging.

Main Methods:

• Proposed two electrode addressing protocols based on current density vectors concentrated in a region of interest.
• One protocol maximizes the magnitude of current density; the other optimizes its distribution.
• Assessed image reconstruction quality using simulations in human and rat models, comparing against a distance-based protocol.

Main Results:

• Maximizing current density magnitude increased concentration by up to 3x.
• Optimizing current density distribution increased vector spread up to 5x.
• The protocol maximizing current density yielded the best image quality for small conductivity changes, reducing average image error by 7%.

Conclusions:

• The protocol that maximizes current density is optimal for fast neural EIT applications.
• This approach enhances the ability to image subtle neural activity.