title: Methods for the computation of templates from quantitative magnetic susceptibility maps (QSM): Toward improved atlas- and voxel-based analyses (VBA).
abstract: To develop and assess a method for the creation of templates for voxel-based analysis (VBA) and atlas-based approaches using quantitative magnetic susceptibility mapping (QSM).
  
  
  
  We studied four strategies for the creation of magnetic susceptibility brain templates, derived as successive extensions of the conventional template generation (CONV) based on only T1-weighted (T1w) images. One method that used only T1w images involved a minor improvement of CONV (U-CONV). One method used only magnetic susceptibility maps as input for template generation (DIRECT), and the other two used a linear combination of susceptibility and T1w images (HYBRID) and an algorithm that directly used both image modalities (MULTI), respectively. The strategies were evaluated in a group of N = 10 healthy human subjects and semiquantitatively assessed by three experienced raters. Template quality was compared statistically via worth estimates (WEs) obtained with a log-linear Bradley-Terry model.
  
  
  
  The overall quality of the templates was better for strategies including both susceptibility and T1w contrast (MULTI: WE = 0.62; HYBRID: WE = 0.21), but the best method depended on the anatomical region of interest. While methods using only one modality resulted in lower WEs, lowest overall WEs were obtained when only T1w images were used (DIRECT: WE = 0.12; U-CONV: WE = 0.05).
  
  
  
  Template generation strategies that employ only magnetic susceptibility contrast or both magnetic susceptibility and T1w contrast produce templates with the highest quality. The optimal approach depends on the anatomical structures of interest. The established approach of using only T1w images (CONV) results in reduced image quality compared to all other approaches studied.
  
  
  
  2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1474-1484.
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Jannis
authors.initials: J
authors.lastname: Hanspach
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Dwyer
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.|Magnetic Resonance Laboratory, IRCCS Don Gnocchi Foundation, Milan, Italy.
authors.forename: Niels P
authors.identifier: 0000-0002-7792-0433
authors.initials: NP
authors.lastname: Bergsland
authors.affiliation: Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich Schiller University Jena, Jena, TH, Germany.
authors.forename: Xiang
authors.initials: X
authors.lastname: Feng
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Jesper
authors.initials: J
authors.lastname: Hagemeier
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Nicola
authors.initials: N
authors.lastname: Bertolino
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Paul
authors.identifier: 0000-0002-7719-7572
authors.initials: P
authors.lastname: Polak
authors.affiliation: Medical Physics Group, Institute of Diagnostic and Interventional Radiology, Jena University Hospital, Friedrich Schiller University Jena, Jena, TH, Germany.|Michael Stifel Center for Data-driven and Simulation Science Jena, Friedrich Schiller University Jena, Jena, TH, Germany.
authors.forename: Jürgen R
authors.initials: JR
authors.lastname: Reichenbach
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.|MRI Clinical and Translational Research Center, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Zivadinov
authors.affiliation: Buffalo Neuroimaging Analysis Center, Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.|MRI Clinical and Translational Research Center, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
authors.forename: Ferdinand
authors.identifier: 0000-0003-0399-9211
authors.initials: F
authors.lastname: Schweser
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping / Q000379:methods*; D003198:Computer Simulation; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
keywords: T1-weighted imaging; magnetic resonance imaging (MRI); normalization; quantitative susceptibility mapping (QSM); template; voxel-based analysis (VBA)