Mid-term Interval Reliability of Multi-echo based Resting-state Functional Connectivity on a Compact 3T Scanner

Motivation: The consistency of cerebral functional connectivity (FC) over mid-term intervals of a few weeks remains unclear given anticipated daily variation in states of emotion or alertness. Multi-echo EPI acquisition (ME) can offer higher signal-to-noise and potentially enhance reliability, compared to single-echo acquisition (SE). Goal(s): To assess mid-term FC reliability with ME RS-fMRI. Approach: Test-retest reliability over a 2-to-3-week interval was evaluated using intra-class correlation (ICC) with ROI-based FC matrix and compared with SE. Results: ME provided higher averaged ICC and detected more connectivity with high ICC than SE. A high- FC matrix thresholded with high ICC was presented. Impact: A reliability-based thresholding method may offer an alternative approach than traditional FC strength-based methods for assessing mid-term brain connectome changes.