title: Intravenous thrombolysis in acute ischemic stroke patients with negative CT perfusion: a case series.
abstract: BACKGROUND
  Computed tomography perfusion (CTP) is a commonly used modality of neurophysiologic imaging to aid the selection of acute ischemic stroke patients for neuroendovascular intervention by identifying the presence of penumbra versus infarcted brain tissue. However many patients present with evidence of cerebral ischemia with normal CTP, and in that case, should intravenous thrombolytics be given?
  
  
  OBJECTIVE
  To demonstrate if tissue-type plasminogen activator (tPA)-eligible stroke patients without perfusion defects demonstrated on CTP would benefit from administration of intravenous thrombolytics.
  
  
  METHODS
  We retrospectively identified patients presenting with acute ischemic symptoms who received intravenous tPA (IV-tPA) from January to June 2012 without a perfusion defect on CTP. Clinical and radiographic findings including the NIHSS at presentation, 24 h, and at discharge, symptomatic and asymptomatic hemorrhagic transformation, and the modified Rankin score at 30 days were collected. A reduction of NIHSS of greater than 4 points or resolution of symptoms was considered significant.
  
  
  RESULTS
  Seventeen patients were identified with a mean NIHSS of 8.2 prior to administration of intravenous thrombolytics, 3.5 after 24 h, and 2.5 at discharge. Among them, 13 patients had significant improvement of NIHSS with a mean reduction of 6.15 points at 24 h. One patient initially improved but had delayed hemorrhagic transformation and died. Two patients had improvement in NIHSS but were not significant and two patients had increased in NIHSS at 24 h, although one eventually improved at discharge. There was no asymptomatic hemorrhagic transformation. Mean mRS at 3 months is 1.76.
  
  
  CONCLUSIONS
  The failure to identify a perfusion deficit by CTP should not be used as a contraindication for intravenous thrombolytics. Criteria for administration of intravenous thrombolytics should still be based on time from symptom onset as previously published by NINDS.
authors.affiliation: Department of Surgery, Division of Neurosurgery, St. John Providence Health System, Detroit, MI, USA.
authors.forename: Ratnesh
authors.initials: R
authors.lastname: Mehra
authors.affiliation: Department of Surgery, Division of Neurosurgery, St. John Providence Health System, Detroit, MI, USA.
authors.forename: Chiu Yuen
authors.initials: CY
authors.lastname: To
authors.affiliation: Department of Surgery, Division of Neurosurgery, St. John Providence Health System, Detroit, MI, USA.
authors.forename: Omar
authors.initials: O
authors.lastname: Qahwash
authors.affiliation: Department of Surgery, Division of Neurosurgery, St. John Providence Health System, Detroit, MI, USA.
authors.forename: Boyd
authors.initials: B
authors.lastname: Richards
authors.affiliation: Department of Surgery, Division of Neurosurgery, St. John Providence Health System, Detroit, MI, USA.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Fessler
keywords: CT; MR diffusion/perfusion; physiological studies; thrombolysis