Disruption of resting-state functional connectivity in acute ischemic stroke: comparisons between right and left hemispheric insults

Abstract

Abstract Background: Few resting-state functional magnetic resonance imaging (RS-fMRI) studies evaluated the impact of acute ischemic changes on cerebral functional connectivity (FC) and its relationship with functional outcomes after acute ischemic stroke (AIS), considering the side and size of lesions. Objective: To characterize alterations of FC of patients with AIS by analyzing 12 large-scale brain networks (NWs) with RS-fMRI. Additionally, we evaluated the impact of side (right (RH) or left (LH) hemisphere) and size (lacunar or non-lacunar) of insult on the disruption of brain NWs. Materials and Methods: 38 patients diagnosed with AIS (19 RH and 19 LH) who performed 3T MRI scans up to 72 hours after stroke were compared to 44 healthy controls. Images were processed and analyzed with the software toolbox UF2C with SPM12. For the first level, we generated individual matrices based on the time series extraction from 70 regions of interest (ROIs) from 12 functional NWs, constructing Pearson’s cross-correlation; the second-level analysis included an analysis of covariance (ANCOVA) to investigate differences between groups. The statistical significance was determined with p<0.05, after correction for multiple comparisons with false discovery rate (FDR) correction. Results: Overall, individual with LH insults developed poorer six months clinical outcomes. A high degree of FC disruption was observed in LH insults (widespread pattern), mainly in non-lacunar lesions. Changes in FC for RH insults did not survive FDR corrections. Conclusion: Our findings demonstrated that LH stroke causes severe FC alterations in the network topological properties, presumably related to impairment in their long-term recovery.