Accelerated spin-echo fMRI using Multisection Excitation by Simultaneous Spin-echo Interleaving (MESSI) with ‘complex-basis’ RF-encoded generalized SLIce Dithered Enhanced Resolution Simultaneous Multi-Slice (MESSI-gSlider-SMS)

High spatiotemporal resolution spin-echo fMRI is challenging as it requires a long echo time to generate BOLD-contrast, resulting in longer repetition times. We propose a new technique, Multisection Excitation by Simultaneous Spin-echo Interleaving (MESSI), which utilizes the dead time in long TE acquisitions to improve the slice-coverage of SE-fMRI. For further accelerations, we combine the MESSI with both ‘complex-basis’ RF-encoded gSlider and conventional-SMS. Compared with standard SE-EPI acquisition with the same TR, the proposed MESSI-gSlider acquisition shows comparable tSNR but with eight-fold increase in slice-coverage. This method should be beneficial for applications requiring high spatiotemporal resolution SE-fMRI with whole-brain coverage.