title: Prevalence of Brain Microbleeds in Alzheimer Disease: A Systematic Review and Meta-Analysis on the Influence of Neuroimaging Techniques.
abstract: OBJECTIVE
  The literature on the prevalence of Alzheimer disease-associated cerebral microbleeds assessed with MR imaging shows considerable heterogeneity in terms of imaging techniques and parameters. Our aim was to perform a meta-analysis of the role of imaging techniques, including image acquisition, field strength and scanner type, and clinical and demographic factors on the reported prevalence of microbleeds in Alzheimer disease.
  
  
  METHODS
  The prevalence of microbleeds was examined with respect to a priori-selected moderating variables via meta-analytic tools of literature reports.
  
  
  RESULTS
  Fourteen unique studies providing 15 microbleed prevalence rates met the selection criteria for inclusion. The aggregate prevalence of microbleeds was 24% (95% CI, 19%-28%). Scan (SWI = 40%, gradient echo = 18%, EPI = 19%) and field strength (slope = 0.39; standard error = 15, P < .01) influenced the prevalence of microbleeds. The associations between microbleeds and age, sex, and global cognitive status were not significant. After updating the literature, the aggregate prevalence remained in the 95% CI range.
  
  
  CONCLUSIONS
  Imaging technique and field strength are strongly associated with the prevalence of microbleeds over the global aggregate. Standardized imaging protocols for identification of microbleeds are recommended to minimize confounds.
authors.affiliation: From the Division of Neurology (A.A.S., G.-Y.H.), Department of Medicine Departments of Paediatrics (A.A.S., A.R.) sepehryaa@alumni.ubc.ca.
authors.forename: A A
authors.identifier: http://orcid.org/0000-0002-6055-4457
authors.initials: AA
authors.lastname: Sepehry
authors.affiliation: Radiology (D.L.); University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: D
authors.identifier: http://orcid.org/0000-0001-9373-1555
authors.initials: D
authors.lastname: Lang
authors.affiliation: From the Division of Neurology (A.A.S., G.-Y.H.), Department of Medicine.
authors.forename: G-Y
authors.identifier: http://orcid.org/0000-0002-8017-0856
authors.initials: GY
authors.lastname: Hsiung
authors.affiliation: Departments of Paediatrics (A.A.S., A.R.).
authors.forename: A
authors.identifier: http://orcid.org/0000-0002-1961-8252
authors.initials: A
authors.lastname: Rauscher
mesh_terms: D000544:Alzheimer Disease / Q000150:complications*; D002543:Cerebral Hemorrhage / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D059906:Neuroimaging / Q000379:methods*; D015995:Prevalence