title: Acute stroke: improved nonenhanced CT detection--benefits of soft-copy interpretation by using variable window width and center level settings.
abstract: OBJECTIVE
  To assess the use of nonstandard, variable window width and level review settings in computed tomography (CT) without contrast material administration in the detection of acute stroke.
  
  
  METHODS
  Nonenhanced CT was performed in 21 patients with acute (< 6 hours) middle cerebral arterial stroke and nine control patients. Two blinded neuroradiologists rated all scans for presence of parenchymal hypoattenuation. Images were reviewed at a picture archiving and communication system (PACS) workstation, with standard, locally determined center level and window width settings of 20 and 80 HU and with variable soft-copy settings initially centered at a level of 32 HU with a width of 8 HU. Reviewers altered settings to accentuate gray and white matter contrast.
  
  
  RESULTS
  With standard viewing parameters, sensitivity and specificity for stroke detection were 57% and 100%. Sensitivity increased to 71% with variable window width and center level settings, without loss of specificity. Receiver operating characteristic analysis revealed a significant improvement in accuracy with nonstandard, soft-copy review settings (P = .03, one-tailed z test).
  
  
  CONCLUSIONS
  In nonehanced CT of the head, detection of ischemic brain parenchyma is facilitated by soft-copy review with variable window width and center level settings to accentuate the contrast between normal and edematous tissue.
authors.affiliation: Department of Radiology, Massachusetts General Hospital, Boston 02114-9657, USA. mlev@partners.org
authors.forename: M H
authors.initials: MH
authors.lastname: Lev
authors.forename: J
authors.initials: J
authors.lastname: Farkas
authors.forename: J J
authors.initials: JJ
authors.lastname: Gemmete
authors.forename: S T
authors.initials: ST
authors.lastname: Hossain
authors.forename: G J
authors.initials: GJ
authors.lastname: Hunter
authors.forename: W J
authors.initials: WJ
authors.lastname: Koroshetz
authors.forename: R G
authors.initials: RG
authors.lastname: Gonzalez
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging; D015588:Observer Variation; D012372:ROC Curve; D011873:Radiology Information Systems; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods