title: Reproducibility of ABC/2 method to determine infarct volume and mismatch percentage with CT perfusion.
abstract: BACKGROUND
  Our aim is to implement a simple, rapid, and reliable method using computed tomography perfusion imaging and clinical judgment to target patients for reperfusion therapy in the hyper-acute stroke setting. We introduce a novel formula (1-infarct volume [CBV]/penumbra volume [MTT] × 100%) to quantify mismatch percentage.
  
  
  METHODS
  Twenty patients with anterior circulation strokes who underwent CT perfusion and received intravenous tissue plasminogen activator (IV tPA) were analyzed retrospectively. Nine blinded viewers determined volume of infarct and ischemic penumbra using the ABC/2 method and also the mismatch percentage.
  
  
  RESULTS
  Interrater reliability using the volumetric formula (ABC/2) was very good (intraclass correlation [ICC] = .9440 and ICC = .8510) for hemodynamic parameters infarct (CBV) and penumbra (MTT). ICC coefficient using the mismatch formula (1-MTT/CBV × 100%) was good (ICC of .635).
  
  
  CONCLUSIONS
  The ABC/2 method of volume estimation on CT perfusion is a reliable and efficient approach to determine infarct and penumbra volumes. The 1-CBV/MTT × 100% formula produces a mismatch percentage assisting providers in communicating the proportion of salvageable brain and guides therapy in the setting of patients with unclear time of onset with potentially salvageable tissue who can undergo mechanical retrieval or intraarterial thrombolytics.
authors: Department of Neurology, University of Utah, Salt Lake City, UT.
authors: Kris F
authors: KF
authors: French
authors: Julie K
authors: JK
authors: Martinez
authors: Adam H
authors: AH
authors: DeHavenon
authors: Natalie R
authors: NR
authors: Weathered
authors: Matthew
authors: M
authors: Grantz
authors: Shawn M
authors: SM
authors: Smith
authors: Michael
authors: M
authors: Wilder
authors: Ulrich A
authors: UA
authors: Rassner
authors: John C
authors: JC
authors: Kircher
authors: L Dana
authors: LD
authors: Dewitt
authors: Jana J
authors: JJ
authors: Wold
authors: Robert E
authors: RE
authors: Hoesch
mesh_terms: D000465:Algorithms; D002533:Cerebral Angiography / Q000379:methods*; D002544:Cerebral Infarction / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D020243:Infarction, Anterior Cerebral Artery / Q000150:complications / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: Stroke; computed tomography; thrombolytics