Advancing whole‐brain BOLD functional MRI in humans at 10.5 T with motion‐robust 3D echo‐planar imaging, parallel transmission, and high‐density radiofrequency receive coils

Abstract Purpose To demonstrate the feasibility and performance of whole‐brain blood oxygen level–dependent functional MRI (fMRI) in humans at 10.5 T by combining motion‐robust three‐dimensional gradient‐echo echo‐planar imaging, parallel transmission, and high‐density radiofrequency (RF) receive coils. Methods Resting‐state fMRI time series were collected in healthy adults at 1.58 mm and approximately 2‐s spatiotemporal resolution using a custom‐built 16‐channel transmit/80‐channel receive RF array. Individualized parallel‐transmission, spatial‐spectral RF pulses were designed to achieve uniform water‐selective excitation across the entire brain without the need for additional fat saturation. Images were reconstructed with navigator‐guided joint motion and field correction. Reconstructed images were preprocessed using fMRIPrep and postprocessed using XCP‐D pipelines. Relevant resting‐state fMRI metrics were evaluated including temporal SNR (tSNR), amplitude of low‐frequency fluctuation, and regional homogeneity. The results were compared with those obtained using uncorrected reconstruction (i.e., using same raw data but without motion or field correction). Results Our motion‐corrected reconstruction largely improved image quality for fMRI time series, reducing motion confounds when compared with uncorrected reconstruction. The reduction in motion confounds translated into an improvement in tSNR, with tSNR averaged across all volunteers being increased by about 11%. Our motion‐corrected reconstruction also improved both amplitude of low‐frequency fluctuation and regional homogeneity in most cortical surfaces and subcortical regions. Conclusion It is feasible to perform quality three‐dimensional whole‐brain blood oxygen level–dependent fMRI in humans at 10.5 T using a new comprehensive motion‐robust imaging method. This work paves the way for promising future applications at 10.5 T aimed at studying brain function and networks with high spatiotemporal resolution.