Ultra-Fast Volumetric Functional Imaging using Single Shot Concentric Shells Trajectories

Benjamin Zahneisen¹, Thimo Grotz¹, Maxim Zaitsev¹, Juergen Hennig¹

MR-encephalography (MREG) has been shown to allow extremely fast and highly sensitive monitoring of functional activation. Recently, it has been shown that the use of a 3D rosette trajectory provides whole brain coverage with an acquisition time of 23ms. However, the rosette trajectory has a very non-uniform k-space sampling density and suffers from off-resonance artifacts. Here, we propose the use of a single shot, variable density, concentric shells trajectory for ultra-fast functional imaging. The method yields very good spatial localization of BOLD-activation. The high sampling rate allows the real time observation of dynamic changes of the BOLD-response (dynamic retinotopic mapping).