Acute stroke: improved nonenhanced CT detection--benefits of soft-copy interpretation by using variable window width and center level settings

Radiology. 1999 Oct;213(1):150-5. doi: 10.1148/radiology.213.1.r99oc10150.


Purpose: 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.

Materials and 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).

Conclusion: 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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acute Disease
  • Adult
  • Aged
  • Aged, 80 and over
  • Brain / diagnostic imaging*
  • Female
  • Humans
  • Infarction, Middle Cerebral Artery / diagnostic imaging*
  • Male
  • Middle Aged
  • Middle Cerebral Artery / diagnostic imaging
  • Observer Variation
  • ROC Curve
  • Radiology Information Systems
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed* / methods