title: Perfusion-CT assessment of infarct core and penumbra: receiver operating characteristic curve analysis in 130 patients suspected of acute hemispheric stroke.
abstract: OBJECTIVE
  Different definitions have been proposed to define the ischemic penumbra from perfusion-CT (PCT) data, based on parameters and thresholds tested only in small pilot studies. The purpose of this study was to perform a systematic evaluation of all PCT parameters (cerebral blood flow, volume [CBV], mean transit time [MTT], time-to-peak) in a large series of acute stroke patients, to determine which (combination of) parameters most accurately predicts infarct and penumbra.
  
  
  METHODS
  One hundred and thirty patients with symptoms suggesting hemispheric stroke < or =12 hours from onset were enrolled in a prospective multicenter trial. They all underwent admission PCT and follow-up diffusion-weighted imaging/fluid-attenuated inversion recovery (DWI/FLAIR); 25 patients also underwent admission DWI/FLAIR. PCT maps were assessed for absolute and relative reduced CBV, reduced cerebral blood flow, increased MTT, and increased time-to-peak. Receiver-operating characteristic curve analysis was performed to determine the most accurate PCT parameter, and the optimal threshold for each parameter, using DWI/FLAIR as the gold standard.
  
  
  RESULTS
  The PCT parameter that most accurately describes the tissue at risk of infarction in case of persistent arterial occlusion is the relative MTT (area under the curve=0.962), with an optimal threshold of 145%. The PCT parameter that most accurately describes the infarct core on admission is the absolute CBV (area under the curve=0.927), with an optimal threshold at 2.0 ml x 100 g(-1).
  
  
  CONCLUSIONS
  In a large series of 130 patients, the optimal approach to define the infarct and the penumbra is a combined approach using 2 PCT parameters: relative MTT and absolute CBV, with dedicated thresholds.
authors.affiliation: Department of Radiology, University of California, San Francisco, CA 94143-0628, USA. Max.Wintermark@radiology.ucsf.edu
authors.forename: Max
authors.initials: M
authors.lastname: Wintermark
authors.forename: Adam E
authors.initials: AE
authors.lastname: Flanders
authors.forename: Birgitta
authors.initials: B
authors.lastname: Velthuis
authors.forename: Reto
authors.initials: R
authors.lastname: Meuli
authors.forename: Maarten
authors.initials: M
authors.lastname: van Leeuwen
authors.forename: Dorit
authors.initials: D
authors.lastname: Goldsher
authors.forename: Carissa
authors.initials: C
authors.lastname: Pineda
authors.forename: Joaquin
authors.initials: J
authors.lastname: Serena
authors.forename: Irene
authors.initials: I
authors.lastname: van der Schaaf
authors.forename: Annet
authors.initials: A
authors.lastname: Waaijer
authors.forename: James
authors.initials: J
authors.lastname: Anderson
authors.forename: Gary
authors.initials: G
authors.lastname: Nesbit
authors.forename: Igal
authors.initials: I
authors.lastname: Gabriely
authors.forename: Victoria
authors.initials: V
authors.lastname: Medina
authors.forename: Ana
authors.initials: A
authors.lastname: Quiles
authors.forename: Scott
authors.initials: S
authors.lastname: Pohlman
authors.forename: Marcel
authors.initials: M
authors.lastname: Quist
authors.forename: Pierre
authors.initials: P
authors.lastname: Schnyder
authors.forename: Julien
authors.initials: J
authors.lastname: Bogousslavsky
authors.forename: William P
authors.initials: WP
authors.lastname: Dillon
authors.forename: Salvador
authors.initials: S
authors.lastname: Pedraza
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume; D001921:Brain / Q000000981:diagnostic imaging*; D002544:Cerebral Infarction / Q000175:diagnosis / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D020521:Stroke / Q000175:diagnosis / Q000000981:diagnostic imaging*; D013997:Time Factors; D014057:Tomography, X-Ray Computed