Simultaneous EEG-fMRI at 7T with adapted EEG leads and reference sensors for high-quality, high-resolution imaging: human evaluation

Motivation: The combination of BOLD-fMRI at 7T with EEG could bring novel insights to neuroscience. However, the combination has remained challenging due to accentuated artifacts and RF-coil constraints. Goal(s): To implement a first-of-its-kind 7T EEG-fMRI framework combining key developments from recent studies, and assess its safety, data quality and functional sensitivity in humans. Approach: Extensive tests in phantom and humans(N=8) including field mapping, structural MRI and fMRI (1.6 and 0.8mm-resolution) acquired with+without EEG. Comparisons of data quality and functional sensitivity. Results: The framework proved safe and feasible with fMRI down to sub-mm resolution, with moderate quality losses and potentially negligible impact on functional sensitivity. Impact: This study characterizes the feasibility of 7T-EEG-fMRI with high sensitivity and acceleration capabilities, which could bring valuable insights to research in e.g. laminar functional connectivity, or localization of epileptogenic sources and their propagation pathways, for clinical diagnostic and pre-surgical planning.