title: Atlas based brain volumetry: How to distinguish regional volume changes due to biological or physiological effects from inherent noise of the methodology.
abstract: Fully-automated regional brain volumetry based on structural magnetic resonance imaging (MRI) plays an important role in quantitative neuroimaging. In clinical trials as well as in clinical routine multiple MRIs of individual patients at different time points need to be assessed longitudinally. Measures of inter- and intrascanner variability are crucial to understand the intrinsic variability of the method and to distinguish volume changes due to biological or physiological effects from inherent noise of the methodology. To measure regional brain volumes an atlas based volumetry (ABV) approach was deployed using a highly elastic registration framework and an anatomical atlas in a well-defined template space. We assessed inter- and intrascanner variability of the method in 51 cognitively normal subjects and 27 Alzheimer dementia (AD) patients from the Alzheimer's Disease Neuroimaging Initiative by studying volumetric results of repeated scans for 17 compartments and brain regions. Median percentage volume differences of scan-rescans from the same scanner ranged from 0.24% (whole brain parenchyma in healthy subjects) to 1.73% (occipital lobe white matter in AD), with generally higher differences in AD patients as compared to normal subjects (e.g., 1.01% vs. 0.78% for the hippocampus). Minimum percentage volume differences detectable with an error probability of 5% were in the one-digit percentage range for almost all structures investigated, with most of them being below 5%. Intrascanner variability was independent of magnetic field strength. The median interscanner variability was up to ten times higher than the intrascanner variability.
authors.affiliation: Neuroimmunology and Multiple Sclerosis Research, Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland; jung diagnostics GmbH, Hamburg, Germany. Electronic address: roland.opfer@jung-diagnostics.de.
authors.forename: Roland
authors.initials: R
authors.lastname: Opfer
authors.affiliation: jung diagnostics GmbH, Hamburg, Germany.
authors.forename: Per
authors.initials: P
authors.lastname: Suppa
authors.affiliation: jung diagnostics GmbH, Hamburg, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Kepp
authors.affiliation: jung diagnostics GmbH, Hamburg, Germany.
authors.forename: Lothar
authors.initials: L
authors.lastname: Spies
authors.affiliation: Neuroimmunology and Multiple Sclerosis Research, Department of Neurology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Sven
authors.initials: S
authors.lastname: Schippling
authors.affiliation: Swiss Epilepsy Centre, Zurich, Switzerland.
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Huppertz
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D015203:Reproducibility of Results; D066127:White Matter / Q000000981:diagnostic imaging / Q000503:physiopathology
keywords: Atlas based brain volumetry; Dartel; Elastic image registration; Intrascanner variability; Magnetic resonance imaging; Repeat scanning