Impact of multi-echo fMRI on the estimate of Integrated Local Correlation

Motivation: The impact of using optimally combined fMRI multi-echo (OC-ME) data versus single-echo (SE) techniques on local resting-state functional connectivity (rs-FC) metrics has not been assessed. Goal(s): The study evaluates the effect of OC-ME versus SE on local brain coherence assessed with Integrated Local Correlation (LCOR). Approach: Resting-state multi-echo data were combined into an optimized timeseries. After preprocessing SE and OC-ME data, LCOR was analyzed to assess differences in local brain coherence between the two approaches. Results: OC-ME data resulted in significantly higher LCOR values compared to the SE approach in the anterior and posterior cingulate cortex and the right and left supramarginal gyrus. Impact: The ME approach enhances local coherence in resting-state fMRI signals from gray matter, aligning with the known reduced thermal noise and optimized BOLD sensitivity of multi-echo data. This improved sensitivity could enable finer comparisons between conditions/groups, especially in clinical studies.