title: Magnetic resonance imaging in experimental stroke and comparison with histology: systematic review and meta-analysis.
abstract: OBJECTIVE
  Because the new era of preclinical stroke research demands improvements in validity and generalizability of findings, moving from single site to multicenter studies could be pivotal. However, the conduct of magnetic resonance imaging (MRI) in stroke remains ill-defined. We sought to assess the variability in the use of MRI for evaluating lesions post stroke and to examine the possibility as an alternative to gold standard histology for measuring the infarct size.
  
  
  METHODS
  We identified animal studies of ischemic stroke reporting lesion sizes using MRI. We assessed the degree of heterogeneity and reporting of scanning protocols, postprocessing methods, study design characteristics, and study quality. Studies performing histological evaluation of infarct size were further selected to compare with corresponding MRI using meta-regression.
  
  
  RESULTS
  Fifty-four articles undertaking a total of 78 different MRI scanning protocols met the inclusion criteria. T2-weighted imaging was most frequently used (83% of the studies), followed by diffusion-weighted imaging (43%). Reporting of the imaging parameters was adequate, but heterogeneity between studies was high. Twelve studies assessed the infarct size using both MRI and histology at corresponding time points, with T2-weighted imaging-based treatment effect having a significant positive correlation with histology (; P<0.001).
  
  
  CONCLUSIONS
  Guidelines for standardized use and reporting of MRI in preclinical stroke are urgently needed. T2-weighted imaging could be used as an effective in vivo alternative to histology for estimating treatment effects based on the extent of infarction; however, additional studies are needed to explore the effect of individual parameters.
authors: From the Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.
authors: Xenios
authors: X
authors: Milidonis
authors: From the Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.
authors: Ian
authors: I
authors: Marshall
authors: From the Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom.
authors: Malcolm R
authors: MR
authors: Macleod
authors: From the Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom. emily.sena@ed.ac.uk.
authors: Emily S
authors: ES
authors: Sena
mesh_terms: D000818:Animals; D002545:Brain Ischemia; D003952:Diagnostic Imaging / Q000379:methods; D004195:Disease Models, Animal; D006652:Histological Techniques; D006801:Humans; D008279:Magnetic Resonance Imaging; D051379:Mice; D010215:Papio; D051381:Rats; D012044:Regression Analysis; D015203:Reproducibility of Results; D012107:Research Design; D020521:Stroke / Q000473:pathology*
keywords: brain ischemia; magnetic resonance imaging; models, animal