title: Differences in CT perfusion summary maps for patients with acute ischemic stroke generated by 2 software packages.
abstract: OBJECTIVE
  Although CT perfusion is a promising tool to support treatment decisions for patients with acute ischemic stroke, it still lacks a standardized method for CTP analysis. The purpose of this study was to assess the variability of the area of infarct core and penumbra as presented in summary maps produced by 2 different software packages.
  
  
  METHODS
  Forty-one CTP image datasets of 26 consecutive patients who presented with acute ischemic stroke were retrospectively evaluated. Identical image datasets were analyzed by using 2 different commercially available CTP analysis software packages, each representing a mainstream of widely used algorithms: delay-sensitive and delay-insensitive. Bland-Altman analyses were performed to evaluate the level of agreement between the 2 methods in determining the area of infarct core and penumbra area in the summary maps.
  
  
  RESULTS
  There was a statistically significant difference in infarct core area (-23.6 ± 25.6 cm(2)) and penumbra area (15.8 ± 25.3 cm(2)) between the 2 software packages. For all the areas presented in the summary maps, the Bland-Altman interval limit of agreement was larger than 100 cm(2).
  
  
  CONCLUSIONS
  The infarct core and penumbra area of CTP summary maps generated by 2 commonly used software packages were significantly different, emphasizing the need for standardization and validation of CTP analysis before it can be applied to patient management in clinical practice.
authors.affiliation: Departments of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, the Netherlands. f.fahmi@amc.uva.nl
authors.forename: F
authors.initials: F
authors.lastname: Fahmi
authors.forename: H A
authors.initials: HA
authors.lastname: Marquering
authors.forename: G J
authors.initials: GJ
authors.lastname: Streekstra
authors.forename: L F M
authors.initials: LF
authors.lastname: Beenen
authors.forename: B K
authors.initials: BK
authors.lastname: Velthuis
authors.forename: E
authors.initials: E
authors.lastname: VanBavel
authors.forename: C B
authors.initials: CB
authors.lastname: Majoie
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002545:Brain Ischemia / Q000150:complications / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012680:Sensitivity and Specificity; D012984:Software; D012986:Software Validation; D020521:Stroke / Q000000981:diagnostic imaging* / Q000209:etiology; D014057:Tomography, X-Ray Computed / Q000379:methods*