title: Perfusion CT to quantify the cerebral vasospasm following subarachnoid hemorrhage.
abstract: OBJECTIVE
  After subarachnoid hemorrhage (SAH), vasospasm is frequent and increases the risk of stroke and poor clinical outcome. The purpose of this study was to identify the best perfusion parameters in perfusion-CT (PCT) able to predict vasospasm diagnosed by angiography after SAH.
  
  
  METHODS
  Seventy-six patients with SAH were investigated by PCT and cerebral angiography. Using regions of interest (ROI) on parametric maps of mean transit time (MTT), time to peak (TTP), cerebral blood volume (CBV) and cerebral blood flow (CBF), PCT data were compared to an arteriographic score in two categories (severe vasospasm: ≥ 50% and non-severe vasospasm: <50%) for each artery. Best PCT predictors of the arteriographic score were tested using multiparametric logistic regression.
  
  
  RESULTS
  Among the 76 patients, PCT data were reliable in 65 patients. Twenty-seven patients had a severe vasospasm. Logistic regression showed that MTT was the best predictor of the arteriographic score. Using MTT, odds ratios having a vasospasm were superior to 3.1 and the occurrence of a vasospasm was accurately predicted in 78.5 to 100%, depending on the artery considered. However, no absolute value of the MTT could be identified to predict the occurrence of vasospasm. In fact, abnormal values of MTT ranged from 123 to 221% (m=146%) of the control values.
  
  
  CONCLUSIONS
  PCT may accurately identify severe vasospasm and might be used as a convenient noninvasive imaging modality to monitor patients with SAH. When detected, severe vasospasm could be confirmed and managed using angiography and endovascular treatment, appropriately.
authors.affiliation: Department of Neuroradiology, CHU Grenoble, University Joseph-Fourier, BP 217, 38043 Grenoble cedex 9, France. VLefournier@chu-grenoble.fr
authors.forename: Virginie
authors.initials: V
authors.lastname: Lefournier
authors.forename: Alexandre
authors.initials: A
authors.lastname: Krainik
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gory
authors.forename: Frédéric
authors.initials: F
authors.lastname: Derderian
authors.forename: Pierre
authors.initials: P
authors.lastname: Bessou
authors.forename: Bertrand
authors.initials: B
authors.lastname: Fauvage
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Le Bas
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Payen
mesh_terms: D000704:Analysis of Variance; D002533:Cerebral Angiography / Q000379:methods*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D055420:Perfusion Imaging / Q000379:methods*; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging* / Q000209:etiology