Resting-State Functional Quantitative Susceptibility Mapping (rsfQSM)

Motivation: Task-based functional Quantitative Susceptibility Mapping (fQSM) shows more localized brain activations than fMRI. Resting-state fMRI reveals brain connectivity networks but resting-state analysis of QSM has not yet been performed and may provide complementary information. Goal(s): To perform a resting-state functional analysis using QSM (rsfQSM) and compare it to rsfMRI, focusing on the Default Mode Network (DMN). Approach: We used seed-based and ICA-based analyses for rsfQSM and assessed the similarity of the DMN to that in rsfMRI with quantitative metrics. Results: The DMN was detected in rsfQSM with spatial similarities to the DMN in rsfMRI. rsfQSM showed weaker and less extensive functional connectivity. Impact: We computed resting-state functional connectivity from magnetic susceptibility maps for the first time, revealing similarities in the default-mode network compared to rsfMRI. This paves the way for new QSM-based explorations of brain function to potentially deepen understanding of neurological diseases.