Improved Temporal SNR of Accelerated EPI Using a FLASH Based GRAPPA Reference Scan

S. Lalith Talagala¹, Joelle E. Sarlls¹, Souheil J. Inati²

Current EPI based fMRI protocols frequently incorporate accelerated parallel acquisition techniques such as GRAPPA and SENSE . These techniques help to reduce EPI distortions and to increase the number of slices per TR. However, we have observed that the temporal SNR of GRAPPA EPI data can be highly inhomogeneous and highly compromised with certain EPI protocols. In this work, we show that the tSNR of GRAPPA accelerated EPI can be made more spatially uniform and enhanced by using a GRAPPA reference scan based on a FLASH acquisition scheme rather than an EPI acquisition scheme.