Ultrafast fMRI of the rodent brain using simultaneous multi-slice EPI

Dr Hsu-Lei Lee
Research Fellow, Queensland Brain Institute, presents: 

Ultrafast fMRI of the rodent brain using simultaneous multi-slice EPI

Increasing the spatial and temporal resolution of functional MRI (fMRI) measurement has shown to benefit the study of neural dynamics and functional interaction. However, acceleration of rodent brain fMRI using parallel and simultaneous multi-slice imaging techniques is hampered by the lack of high-density phased-array coils for the small brain. To overcome this limitation, we adapted phase-offset multiplanar and blipped-controlled aliasing echo planar imaging (EPI) to enable simultaneous multi-slice fMRI of the mouse brain using a single loop coil on a 9.4T scanner.

Four slice bands can be simultaneously acquired to cover the whole brain at a temporal resolution of 300ms or the whole cerebrum at 150ms. In a task-based fMRI study using a visual stimulus, multiband EPI with increased temporal samples showed an increase in z-score and activation in the visual cortex. Resting-state fMRI shows reliable detection of bilateral connectivity by both single-band and multiband EPI. We have demonstrated a practical method that can enable unparalleled fast whole-brain fMRI for preclinical studies, without the need for hardware. This technique can be used to increase sensitivity, distinguish transient response or acquire high spatiotemporal resolution fMRI.