title: Signal Fluctuation Sensitivity: An Improved Metric for Optimizing Detection of Resting-State fMRI Networks.
abstract: Task-free connectivity analyses have emerged as a powerful tool in functional neuroimaging. Because the cross-correlations that underlie connectivity measures are sensitive to distortion of time-series, here we used a novel dynamic phantom to provide a ground truth for dynamic fidelity between blood oxygen level dependent (BOLD)-like inputs and fMRI outputs. We found that the de facto quality-metric for task-free fMRI, temporal signal to noise ratio (tSNR), correlated inversely with dynamic fidelity; thus, studies optimized for tSNR actually produced time-series that showed the greatest distortion of signal dynamics. Instead, the phantom showed that dynamic fidelity is reasonably approximated by a measure that, unlike tSNR, dissociates signal dynamics from scanner artifact. We then tested this measure, signal fluctuation sensitivity (SFS), against human resting-state data. As predicted by the phantom, SFS-and not tSNR-is associated with enhanced sensitivity to both local and long-range connectivity within the brain's default mode network.
authors.affiliation: Department of Biomedical Engineering, Stony Brook University School of Medicine Stony Brook, NY, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: DeDora
authors.affiliation: Department of Biomedical Engineering, Stony Brook University School of Medicine Stony Brook, NY, USA.
authors.forename: Sanja
authors.initials: S
authors.lastname: Nedic
authors.affiliation: Department of Biomedical Engineering, Stony Brook University School of Medicine Stony Brook, NY, USA.
authors.forename: Pratha
authors.initials: P
authors.lastname: Katti
authors.affiliation: Department of Biomedical Engineering, Stony Brook University School of Medicine Stony Brook, NY, USA.
authors.forename: Shafique
authors.initials: S
authors.lastname: Arnab
authors.affiliation: Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General HospitalCharlestown, MA, USA; Department of Radiology, Harvard Medical SchoolBoston, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of TechnologyCambridge, MA, USA.
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Wald
authors.affiliation: McGovern Institute for Brain Research at MIT, Massachusetts Institute of Technology Boston, MA, USA.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Takahashi
authors.affiliation: Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General HospitalCharlestown, MA, USA; Department of Psychology, Center for Brain Science, Harvard UniversityCambridge, MA, USA.
authors.forename: Koene R A
authors.initials: KR
authors.lastname: Van Dijk
authors.affiliation: Department of Biomedical Engineering, Stony Brook University School of Medicine Stony Brook, NY, USA.
authors.forename: Helmut H
authors.initials: HH
authors.lastname: Strey
authors.affiliation: Department of Biomedical Engineering, Stony Brook University School of MedicineStony Brook, NY, USA; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General HospitalCharlestown, MA, USA; Department of Radiology, Harvard Medical SchoolBoston, MA, USA; McGovern Institute for Brain Research at MIT, Massachusetts Institute of TechnologyBoston, MA, USA.
authors.forename: Lilianne R
authors.initials: LR
authors.lastname: Mujica-Parodi
keywords: Functional MRI; dynamic phantom; fidelity; resting state connectivity; signal fluctuation sensitivity; temporal signal to noise ratio