title: Automated estimation of salvageable tissue: Comparison with expert readers.
abstract: OBJECTIVE
  To assess the performance of an automatic perfusion-diffusion mismatch outlining algorithm, in a cohort of acute ischemic stroke patients imaged as part of a multicenter study.
  
  
  METHODS
  Magnetic resonance imaging (MRI) from 167 patients with anterior circulation strokes scanned at either 3T or 1.5T systems were analyzed retrospectively through an automatic perfusion-diffusion mismatch detection algorithm. In addition, four expert raters manually outlined perfusion lesions on time-to-peak (TTP) maps and diffusion lesions on diffusion-weighted images (DWI), and reference perfusion-diffusion mismatch masks were obtained as the areas where at least three experts were in agreement that tissue was part of the perfusion-weighted imaging (PWI) lesion, but not the diffusion lesion. Per-subject analyses of mismatch volumes and mismatch overlap were subsequently performed.
  
  
  RESULTS
  The use of the automatic perfusion-diffusion mismatch detection algorithm resulted in a 4.0 ml mean (standard deviation 28.7 ml) difference in mismatch volume compared to the reference expert consensus (Pearson correlation, r = 0.91, P < 0.0001). The median spatial agreement was 0.71, with an interquartile range of 0.28.
  
  
  CONCLUSIONS
  We demonstrated excellent agreement between the perfusion-diffusion mismatch masks estimated by our proposed automatic algorithm and those achieved by expert consensus.
authors.affiliation: Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Mikkel B
authors.initials: MB
authors.lastname: Hansen
authors.affiliation: Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Kartheeban
authors.initials: K
authors.lastname: Nagenthiraja
authors.affiliation: Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Lars R
authors.initials: LR
authors.lastname: Ribe
authors.affiliation: Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.|Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Kristina H
authors.initials: KH
authors.lastname: Dupont
authors.affiliation: Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.|Department of Neuroradiology, Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Leif
authors.initials: L
authors.lastname: Østergaard
authors.affiliation: Center of Functionally Integrative Neuroscience and MINDLab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors.forename: Kim
authors.initials: K
authors.lastname: Mouridsen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001921:Brain / Q000473:pathology*; D002983:Clinical Competence; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020521:Stroke / Q000473:pathology*
keywords: PWI-DWI mismatch segmentation; acute stroke; and decision support; diffusion lesion; perfusion lesion