title: Intra- and interscanner variability of magnetic resonance imaging based volumetry in multiple sclerosis.
abstract: Brain volumetric measurements in multiple sclerosis (MS) reflect not only disease-specific processes but also other sources of variability. The latter has to be considered especially in multicenter and longitudinal studies. Here, we compare data generated by three different 3-Tesla magnetic resonance scanners (Philips Achieva; Siemens Verio; GE Signa MR750). We scanned two patients diagnosed with relapsing remitting MS six times per scanner within three weeks (T1w and FLAIR, 3D). We assessed T2-hyperintense lesions by an automated lesion segmentation tool and determined volumes of grey matter (GM), white matter (WM) and whole brain (GM+WM) from the lesion-filled T1-weighted images using voxel-based morphometry (SPM8/VBM8) and SIENAX (FSL). We measured cortical thickness using FreeSurfer from both, lesion-filled and original T1-weighted images. We quantified brain volume changes with SIENA. In both patients, we found significant differences in total lesion volume, global brain tissue volumes and cortical thickness measures between the scanners. Morphometric measures varied remarkably between repeated scans at each scanner, independent of the brain imaging software tool used. We conclude that for cross-sectional multicenter studies, the effect of different scanners has to be taken into account. For longitudinal monocentric studies, the expected effect size should exceed the size of false positive findings observed in this study. Assuming a physiological loss of brain volume of about 0.3% per year in healthy adult subjects (Good et al., 2001), which may double in MS (De Stefano et al., 2010; De Stefano et al., 2015), with current tools reliable estimation of brain atrophy in individual patients is only possible over periods of several years.
authors.affiliation: Neurology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM-Neuroimaging Center, Technische Universität München, Munich, Germany. Electronic address: viola.biberacher@tum.de.
authors.forename: Viola
authors.initials: V
authors.lastname: Biberacher
authors.affiliation: TUM-Neuroimaging Center, Technische Universität München, Munich, Germany; Statistics, Ludwig-Maximilians-Universität München, Ludwigstr. 33, 80539 Munich, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Schmidt
authors.affiliation: Neurology, University of California San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94158, United States.
authors.forename: Anisha
authors.initials: A
authors.lastname: Keshavan
authors.affiliation: Neurology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM-Neuroimaging Center, Technische Universität München, Munich, Germany.
authors.forename: Christine C
authors.initials: CC
authors.lastname: Boucard
authors.affiliation: Neurology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM-Neuroimaging Center, Technische Universität München, Munich, Germany.
authors.forename: Ruthger
authors.initials: R
authors.lastname: Righart
authors.affiliation: Neuroimaging Core Unit, Max Planck Institute of Psychiatry, Kraepelinstr. 2-10, 80804 Munich, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Sämann
authors.affiliation: Neuroradiology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Preibisch
authors.affiliation: Neuroradiology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fröbel
authors.affiliation: Neurology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
authors.forename: Lilian
authors.initials: L
authors.lastname: Aly
authors.affiliation: Neurology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), Feodor-Lynen-Str. 17, 81377 Munich, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Hemmer
authors.affiliation: Neuroradiology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
authors.forename: Claus
authors.initials: C
authors.lastname: Zimmer
authors.affiliation: Neurology, University of California San Francisco, 675 Nelson Rising Lane, San Francisco, CA 94158, United States.
authors.forename: Roland G
authors.initials: RG
authors.lastname: Henry
authors.affiliation: Neurology, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany; TUM-Neuroimaging Center, Technische Universität München, Munich, Germany.
authors.forename: Mark
authors.initials: M
authors.lastname: Mühlau
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000000981:diagnostic imaging*; D066264:Datasets as Topic; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000592:standards*; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D066127:White Matter / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Magnetic resonance imaging; Multiple sclerosis; Scanner-related variability