fMRI Using GRAPPA EPI with High Spatial Resolution Improves BOLD Signal Detection at 3T

We compared GRAPPA parallel MRI (pMRI) to regular MRI (non-GRAPPA) for BOLD fMRI while keeping all other parameters fixed. We acquired both GRAPPA and non-GRAPPA images using a high resolution as well as a low resolution EPI matrix. We found significantly larger values of percent BOLD signal when comparing higher resolution acquisitions to lower resolution ones, independently of whether data were acquired with GRAPPA EPI or with regular EPI. We also demonstrated no loss of functional activation or BOLD signal when comparing GRAPPA to non-GRAPPA while keeping the same spatial resolution. We propose to use pMRI to gain the ability to perform whole-brain acquisition at higher spatial resolution with TE in the 30-40 ms range for optimal BOLD detection at 3T, or at faster scan times. To this end, we conclude that GRAPPA pMRI is advantageous for BOLD fMRI and whole-brain EPI acquisition at high spatial resolution.