Non-Stationarity of Resting-State Connectivity in Patients with Brain Tumors in the Awake and Anesthetized State

Motivation: Map temporal fluctuations of functional connectivity (FC) in anesthetized brain tumor patients. Goal(s): Map static FC (sFC), dynamic inter-region FC (dFC), and test-retest reliability between awake and anesthetized states in patients undergoing resection of brain tumors. Approach: A sliding-window xDF method was developed to estimate variance of the correlation in spatial-temporal resolution resting-state fMRI, considering nonstationary autocorrelation and cross-correlation. Results: The largest decrease in sFC during anesthesia was observed across, rather than within, networks. The sliding-window xDF increased sensitivity compared to the static model. Test-retest reliability between cortical areas was higher during anesthesia versus awake state, in contrast to subcortical and cortical-subcortical dFC. Impact: These results demonstrate the feasibility of performing resting-state functional connectivity studies in intraoperative settings with high spatial-temporal resolution. The higher test-retest reliability within cortical areas during anesthesia versus awake state informs the design of minimum duration intra-operative resting-state fMRI protocols.