Preliminary Whole-Brain Functional Electrical Properties Tomography using Gradient-Echo Echo-Planar Imaging

Motivation: Electrical properties tomography (EPT) can reveal brain tissue conductivity changes during functional activation. Previous attempts have used sequences with low resolution and limited coverage, and required separate acquisitions to generate functional MRI (fMRI) and EPT (fEPT). Goal(s): To investigate the feasibility of high-resolution whole-brain fEPT and simultaneous fMRI using gradient-echo EPI (GRE-EPI). Approach: Two healthy volunteers were scanned using GRE-EPI during a visual stimulation paradigm. Conductivity maps calculated using phase-based EPT were analysed for functional activation. Results: We observed small regions of positive and negative fEPT visual activation, co-localised with fMRI activations. These findings are reproducible across subjects and coil configurations. Impact: Calculating whole-brain functional Electrical Properties Tomography (fEPT) and BOLD fMRI simultaneously using a high-resolution multi-echo GRE-EPI sequence will allow fMRI studies to reveal functional conductivity changes, opening up a new dimension with potential for new clinical and research applications.