FMRI using 1D “linescan” and 2D imaging are also often equally sensitive: comparing SNR efficiency in theory and practice

Motivation: High-resolution 1D linescan MRI for imaging cerebral cortical layers has seen renewed interest, but concerns about low SNR relative to resolution-matched 2D acquisitions exist. Goal(s): We demonstrate that 1D linescan and conventional 2D acquisitions are often equally sensitive, with 1D linescan in some cases being preferable for 7T fMRI. Approach: We calculated theoretical SNR efficiencies for matched 1D and 2D gradient-echo BOLD fMRI protocols, characterized practical differences, and experimentally compared time-series tSNR efficiency in a human volunteer. Results: We demonstrate comparable SNR efficiencies between 1D linescan and conventional 2D imaging, suggesting that 1D linescan is a viable option for human laminar fMRI. Impact: We address concerns that 1D linescan for BOLD-fMRI has limited SNR compared to equivalent 2D scans. Our results show comparable SNR efficiencies between these two methods, highlighting the benefits of 1D linescan for future studies of human cerebral cortical layers.