title: Middle cerebral artery (MCA) susceptibility sign at susceptibility-based perfusion MR imaging: clinical importance and comparison with hyperdense MCA sign at CT.
abstract: OBJECTIVE
  To describe the radiologic findings of susceptibility changes in acute middle cerebral artery (MCA) thromboembolism detected with three-dimensional (3D) susceptibility-based perfusion magnetic resonance (MR) imaging and to compare the detectability and clinical value of this sign with those of the hyperdense MCA sign at computed tomography (CT).
  
  
  METHODS
  Twenty-three patients (mean age, 55 years) underwent CT and MR imaging within the first 6 hours after the onset of acute MCA stroke. The hyperdense MCA sign at CT and the presence of susceptibility changes in acute thromboembolism as depicted on T2*-weighted 3D perfusion MR images were assessed. The presence of each sign was correlated with clinical presentation.
  
  
  RESULTS
  The sensitivity of the hyperdense MCA sign at CT was 54% (negative predictive value, 71%) compared with 82% (negative predictive value, 86%) for the susceptibility changes at MR imaging. There were no false-positive CT or MR readings. The presence of the MCA susceptibility sign correlated positively with the initial clinical presentation (chi(2) = 7.987, P =.009, Spearman rho = 0.589). However, neither of the signs was a predictor for clinical outcome in cases of spontaneous MCA stroke.
  
  
  CONCLUSIONS
  In addition to the information traditionally provided with reconstructed perfusion parameter maps, 3D susceptibility-based perfusion MR images allow the identification of acute MCA thromboembolism with a sensitivity higher than that of CT.
authors.affiliation: Department of Radiology, University of Bonn, Sigmund-Freud-Strasse 25, D-53105 Bonn, Germany. flacke@uni-bonn.de
authors.forename: S
authors.initials: S
authors.lastname: Flacke
authors.forename: H
authors.initials: H
authors.lastname: Urbach
authors.forename: E
authors.initials: E
authors.lastname: Keller
authors.forename: F
authors.initials: F
authors.lastname: Träber
authors.forename: A
authors.initials: A
authors.lastname: Hartmann
authors.forename: J
authors.initials: J
authors.lastname: Textor
authors.forename: J
authors.initials: J
authors.lastname: Gieseke
authors.forename: W
authors.initials: W
authors.lastname: Block
authors.forename: P J
authors.initials: PJ
authors.lastname: Folkers
authors.forename: H H
authors.initials: HH
authors.lastname: Schild
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D002560:Cerebrovascular Circulation / Q000502:physiology; D016009:Chi-Square Distribution; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis / Q000000981:diagnostic imaging; D002546:Ischemic Attack, Transient / Q000175:diagnosis / Q000000981:diagnostic imaging; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D020521:Stroke / Q000175:diagnosis / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome