title: Correlations between cerebral arterial velocities, blood flow, and delayed ischemia after subarachnoid hemorrhage.
abstract: OBJECTIVE
  Elevated middle cerebral erythrocyte velocities and tissue hypoperfusion have been correlated with delayed ischemia after subarachnoid hemorrhage, but few studies have compared serial arterial velocities with cerebral blood flow and neurological deficits.
  
  
  METHODS
  Serial measurements of middle cerebral velocities, using transcranial Doppler ultrasonography, were performed in 34 patients after subarachnoid hemorrhage and correlated with cerebral blood flow, measured in 20 of the 34 using single-photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime and neurological evidence of delayed ischemia.
  
  
  RESULTS
  In 16 patients without delayed ischemia, eight had evidence of vasospasm (greater than 120 cm/sec), but only one of seven had hypoperfusion, suggesting that vasospasm might be more common than hypoperfusion in this group (p = 0.1). In 10 patients with delayed ischemia and a lateralizing deficit, both asymmetrical middle cerebral vasospasm (eight of nine with vasospasm) and hypoperfusion (six of six studied) were concordant with the clinically ischemic hemisphere (p less than 0.05). Vasospasm occurred with nonlateralized delayed ischemia in seven of eight patients and with hypoperfusion in five of six, affecting the anterior cerebral territory in three.
  
  
  CONCLUSIONS
  Concordant vasospasm and hypoperfusion were most often present in patients with delayed ischemia and lateralizing neurological deficits. Discordant results reflect inherent limitations and the different levels of the circulation monitored by the two techniques.
authors.affiliation: University Departments of Medicine, Royal Melbourne Hospital, Victoria, Australia.
authors.forename: S M
authors.initials: SM
authors.lastname: Davis
authors.forename: J T
authors.initials: JT
authors.lastname: Andrews
authors.forename: M
authors.initials: M
authors.lastname: Lichtenstein
authors.forename: S C
authors.initials: SC
authors.lastname: Rossiter
authors.forename: A H
authors.initials: AH
authors.lastname: Kaye
authors.forename: J
authors.initials: J
authors.lastname: Hopper
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000209:etiology*; D002536:Cerebral Arteries; D002560:Cerebrovascular Circulation; D006801:Humans; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging / Q000209:etiology; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000000981:diagnostic imaging; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014463:Ultrasonography