title: ICA-based artifact removal diminishes scan site differences in multi-center resting-state fMRI.
abstract: Resting-state fMRI (R-fMRI) has shown considerable promise in providing potential biomarkers for diagnosis, prognosis and drug response across a range of diseases. Incorporating R-fMRI into multi-center studies is becoming increasingly popular, imposing technical challenges on data acquisition and analysis, as fMRI data is particularly sensitive to structured noise resulting from hardware, software, and environmental differences. Here, we investigated whether a novel clean up tool for structured noise was capable of reducing center-related R-fMRI differences between healthy subjects. We analyzed three Tesla R-fMRI data from 72 subjects, half of whom were scanned with eyes closed in a Philips Achieva system in The Netherlands, and half of whom were scanned with eyes open in a Siemens Trio system in the UK. After pre-statistical processing and individual Independent Component Analysis (ICA), FMRIB's ICA-based X-noiseifier (FIX) was used to remove noise components from the data. GICA and dual regression were run and non-parametric statistics were used to compare spatial maps between groups before and after applying FIX. Large significant differences were found in all resting-state networks between study sites before using FIX, most of which were reduced to non-significant after applying FIX. The between-center difference in the medial/primary visual network, presumably reflecting a between-center difference in protocol, remained statistically significant. FIX helps facilitate multi-center R-fMRI research by diminishing structured noise from R-fMRI data. In doing so, it improves combination of existing data from different centers in new settings and comparison of rare diseases and risk genes for which adequate sample size remains a challenge.
authors.affiliation: Department of Radiology, Leiden University Medical Centre Leiden, Netherlands ; FMRIB, Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford Oxford, UK.
authors.forename: Rogier A
authors.initials: RA
authors.lastname: Feis
authors.affiliation: FMRIB, Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford Oxford, UK.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Smith
authors.affiliation: FMRIB, Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford Oxford, UK ; Department of Psychiatry, University of Oxford Oxford, UK.
authors.forename: Nicola
authors.initials: N
authors.lastname: Filippini
authors.affiliation: FMRIB, Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford Oxford, UK.
authors.forename: Gwenaëlle
authors.initials: G
authors.lastname: Douaud
authors.affiliation: Department of Radiology, Leiden University Medical Centre Leiden, Netherlands ; Department of Neurology, Erasmus Medical Centre Rotterdam, Netherlands.
authors.forename: Elise G P
authors.initials: EG
authors.lastname: Dopper
authors.affiliation: FMRIB, Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford Oxford, UK ; Department of Psychiatry, University of Oxford Oxford, UK.
authors.forename: Verena
authors.initials: V
authors.lastname: Heise
authors.affiliation: FMRIB, Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford Oxford, UK.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Trachtenberg
authors.affiliation: Department of Neurology, Erasmus Medical Centre Rotterdam, Netherlands.
authors.forename: John C
authors.initials: JC
authors.lastname: van Swieten
authors.affiliation: Department of Radiology, Leiden University Medical Centre Leiden, Netherlands ; Leiden Institute for Brain and Cognition, Leiden University Leiden, Netherlands.
authors.forename: Mark A
authors.initials: MA
authors.lastname: van Buchem
authors.affiliation: Department of Radiology, Leiden University Medical Centre Leiden, Netherlands ; Leiden Institute for Brain and Cognition, Leiden University Leiden, Netherlands ; Institute of Psychology, Leiden University Leiden, Netherlands.
authors.forename: Serge A R B
authors.initials: SA
authors.lastname: Rombouts
authors.affiliation: FMRIB, Nuffield Department of Clinical Neurosciences, Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford Oxford, UK ; Department of Psychiatry, University of Oxford Oxford, UK.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Mackay
keywords: dual regression; independent component analysis; multi-center analysis; resting-state functional MRI; structured noise reduction