Pushing the Limits: Ultrafast 2D Accelerated High Resolution Whole-Head Volumetric Functional Imaging at 7 Tesla

Tram Nguyen¹, Steen Moeller², Ute Goerke², Essa Yacoub², Kamil Ugurbil²

In the tendency towards high-field imaging, three-dimensional (3D) acquisition has potential advantages over its two-dimensional counterpart for functional MRI (fMRI). However, multi-slice 2D-EPI methods remain the conventional sequence in fMRI. Although various advanced 3D schemes have alternatively been applied, they come with individual limitations and are not widely available. The 3D-EPI sequence similarly presents temporal constraints, but holds the potential to be feasible by using the increased signal- and contrast-to-noise ratio of ultrahigh magnetic fields combined with the higher parallel imaging performance feasible at ultra-high fields. A hybrid 3D-EPI then offers the possibility for high 2D acceleration. This potential is exploited in this study at 7 Tesla to overcome the limitations and compare results with 2D acquisition and 1D acceleration. Results show the feasibility of a highly accelerated hybrid 3D-EPI scheme for high resolution whole-head acquisition in high-field fMRI, presenting excellent functional results.