title: Systematic review of perfusion imaging with computed tomography and magnetic resonance in acute ischemic stroke: heterogeneity of acquisition and postprocessing parameters: a translational medicine research collaboration multicentre acute stroke imaging study.
abstract: OBJECTIVE
  Heterogeneity of acquisition and postprocessing parameters for magnetic resonance- and computed tomography-based perfusion imaging in acute stroke may limit comparisons between studies, but the current degree of heterogeneity in the literature has not been precisely defined.
  
  
  METHODS
  We examined articles published before August 30, 2009 that reported perfusion thresholds, average lesion perfusion values, or correlations of perfusion deficit volumes from acute stroke patients <24 hours postictus. We compared acquisition parameters from published studies with guidance from the Acute Stroke Imaging Research Roadmap(1). In addition, we assessed the consistency of postprocessing parameters.
  
  
  RESULTS
  Twenty computed tomography perfusion and 49 perfusion-weighted imaging studies were included from 7152 articles. Although certain parameters were reported frequently, consistently, and in line with the Roadmap proposals, we found substantial heterogeneity in other parameters, and there was considerable variation and underreporting of postprocessing methodology.
  
  
  CONCLUSIONS
  There is substantial scope to increase homogeneity in future studies, eg, through reporting standards.
authors: Institute of Neuroscience & Psychology, University of Glasgow, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK.
authors: Krishna A
authors: KA
authors: Dani
authors: Ralph G R
authors: RG
authors: Thomas
authors: Francesca M
authors: FM
authors: Chappell
authors: Kirsten
authors: K
authors: Shuler
authors: Keith W
authors: KW
authors: Muir
authors: Joanna M
authors: JM
authors: Wardlaw
mesh_terms: D002545:Brain Ischemia / Q000150:complications / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods / Q000592:standards*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000592:standards* / Q000706:statistics & numerical data; D020521:Stroke / Q000150:complications / Q000473:pathology*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000592:standards* / Q000706:statistics & numerical data; D057170:Translational Research, Biomedical