title: Automated Infarct Core Volumetry Within the Hypoperfused Tissue: Technical Implementation and Evaluation.
abstract: OBJECTIVE
  The aim of this study was to develop a rapid and fully automatic infarct core and tissue at risk volumetry approach in acute ischemic stroke.
  
  
  METHODS
  We evaluated an algorithm in which segmentation was restricted to 1 hemisphere and the potential lesion characterized on the basis of the perfusion parameter Tmax with a region-wise comparison of local histograms to its mirrored counterpart.
  
  
  RESULTS
  We applied the "Tmax inside" method to 30 cases of a public data set with ground-truth segmentations for diffusion-weighted and perfusion magnetic resonance imaging. Lesions were robustly identified with significantly higher dice coefficients (apparent diffusion coefficient, 0.83 ± 0.22; Tmax, 0.80 ± 0.05, compared with 0.53 ± 0.27 and 0.56 ± 0.18) than for a global thresholding approach.
  
  
  CONCLUSIONS
  The proposed "Tmax inside" method is superior to the commonly used global thresholding approach. Furthermore, the method allows evaluating changes in cerebral blood volume and blood flow by taking the counterpart in the healthy hemisphere as a patient-individual reference.
authors.affiliation: From the Departments of *Radiology, Medical Physics, †Neuroradiology, and ‡Neurology, University Medical Center Freiburg, Freiburg, Germany.
authors.forename: Elias
authors.initials: E
authors.lastname: Kellner
authors.forename: Marco
authors.initials: M
authors.lastname: Reisert
authors.forename: Valerij G
authors.initials: VG
authors.lastname: Kiselev
authors.forename: Christoph J
authors.initials: CJ
authors.lastname: Maurer
authors.forename: Lena-Alexandra
authors.initials: LA
authors.lastname: Beume
authors.forename: Horst
authors.initials: H
authors.lastname: Urbach
authors.forename: Karl
authors.initials: K
authors.lastname: Egger
mesh_terms: D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D018810:Magnetic Resonance Angiography; D020521:Stroke / Q000000981:diagnostic imaging / Q000473:pathology*