title: A priori collaboration in population imaging: The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement consortium.
abstract: BACKGROUND
  Virchow-Robin spaces (VRS), or perivascular spaces, are compartments of interstitial fluid enclosing cerebral blood vessels and are potential imaging markers of various underlying brain pathologies. Despite a growing interest in the study of enlarged VRS, the heterogeneity in rating and quantification methods combined with small sample sizes have so far hampered advancement in the field.
  
  
  METHODS
  The Uniform Neuro-Imaging of Virchow-Robin Spaces Enlargement (UNIVRSE) consortium was established with primary aims to harmonize rating and analysis (www.uconsortium.org). The UNIVRSE consortium brings together 13 (sub)cohorts from five countries, totaling 16,000 subjects and over 25,000 scans. Eight different magnetic resonance imaging protocols were used in the consortium.
  
  
  RESULTS
  VRS rating was harmonized using a validated protocol that was developed by the two founding members, with high reliability independent of scanner type, rater experience, or concomitant brain pathology. Initial analyses revealed risk factors for enlarged VRS including increased age, sex, high blood pressure, brain infarcts, and white matter lesions, but this varied by brain region.
  
  
  CONCLUSIONS
  Early collaborative efforts between cohort studies with respect to data harmonization and joint analyses can advance the field of population (neuro)imaging. The UNIVRSE consortium will focus efforts on other potential correlates of enlarged VRS, including genetics, cognition, stroke, and dementia.
authors.affiliation: Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands; Department of Radiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Hieab H H
authors.initials: HH
authors.lastname: Adams
authors.affiliation: Department of Ophthalmology, National University of Singapore, Singapore; Memory Aging and Cognition Center, National University Health System, Singapore.
authors.forename: Saima
authors.initials: S
authors.lastname: Hilal
authors.affiliation: Department of Neurology, Medical University of Graz, Graz, Austria.
authors.forename: Petra
authors.initials: P
authors.lastname: Schwingenschuh
authors.affiliation: German Center for Neurodegenerative Diseases (DZNE), Site Rostock/ Greifswald, Greifswald, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Wittfeld
authors.affiliation: Genetic Epidemiology Unit, Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Sven J
authors.initials: SJ
authors.lastname: van der Lee
authors.affiliation: Imaging of Dementia and Aging (IDeA) Laboratory, Department of Neurology and Center for Neuroscience, University of California at Davis, Davis, CA, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: DeCarli
authors.affiliation: Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands; Department of Radiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Meike W
authors.initials: MW
authors.lastname: Vernooij
authors.affiliation: Department of Neurology, Medical University of Graz, Graz, Austria.
authors.forename: Petra
authors.initials: P
authors.lastname: Katschnig-Winter
authors.affiliation: Institute for Community Medicine, University Medicine Greifswald, Greifswald, Germany; Section of Biomedical Image Analysis, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Mohamad
authors.initials: M
authors.lastname: Habes
authors.affiliation: Memory Aging and Cognition Center, National University Health System, Singapore.
authors.forename: Christopher
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Neurology, Boston University School of Medicine, Boston, MA, USA; Framingham Heart Study, Framingham, MA, USA.
authors.forename: Sudha
authors.initials: S
authors.lastname: Seshadri
authors.affiliation: Genetic Epidemiology Unit, Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Cornelia M
authors.initials: CM
authors.lastname: van Duijn
authors.affiliation: Department of Ophthalmology, National University of Singapore, Singapore; Memory Aging and Cognition Center, National University Health System, Singapore.
authors.forename: M Kamran
authors.initials: MK
authors.lastname: Ikram
authors.affiliation: German Center for Neurodegenerative Diseases (DZNE), Site Rostock/ Greifswald, Greifswald, Germany; Department of Psychiatry and Psychotherapy, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Grabe
authors.affiliation: Department of Neurology, Medical University of Graz, Graz, Austria.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Schmidt
authors.affiliation: Department of Epidemiology, Erasmus MC, Rotterdam, The Netherlands; Department of Radiology, Erasmus MC, Rotterdam, The Netherlands; Department of Neurology, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: M Arfan
authors.initials: MA
authors.lastname: Ikram
keywords: Cerebrovascular disease; Dementia; Magnetic resonance imaging; Population based; Population imaging; Risk factors; Stroke; Virchow-Robin spaces