title: Positron emission tomographic cerebral perfusion disturbances and transcranial Doppler findings among patients with neurological deterioration after subarachnoid hemorrhage.
abstract: OBJECTIVE
  After aneurysmal subarachnoid hemorrhage, approximately 30% of patients experience delayed neurological deficits, related in part to arterial vasospasm and dysautoregulation. Transcranial Doppler (TCD) ultrasonography is commonly used to noninvasively detect arterial vasospasm. We studied cerebral perfusion patterns and associated TCD indices for 25 patients who developed clinical signs of delayed neurological deficits.
  
  
  METHODS
  Patients were treated in a neurosurgical intensive care unit and were studied if they exhibited delayed focal or global neurological deterioration. Positron emission tomographic cerebral blood flow (CBF) studies and TCD studies measuring the mean flow velocity (FV) of the middle cerebral artery and the middle cerebral artery FV/internal carotid artery FV ratio (with the internal carotid artery FV being measured extracranially at the cranial base) were performed. Glasgow Outcome Scale scores were assessed at 6 months.
  
  
  RESULTS
  A markedly heterogeneous pattern of CBF distribution was observed, with hyperemia, normal CBF values, and reduced flow being observed among patients with delayed neurological deficits. TCD indices were not indicative of the cerebral perfusion findings. The mean CBF value was slightly lower for patients who did not survive (32.3 ml/100 g/min), compared with those who did survive (36.0 ml/100 g/min, P = 0.05).
  
  
  CONCLUSIONS
  Among patients who developed delayed neurological deficits after aneurysmal subarachnoid hemorrhage, a wide range of cerebral perfusion disturbances was observed, calling into question the traditional concept of large-vessel vasospasm. Commonly used TCD indices do not reflect cerebral perfusion values.
authors.affiliation: Wolfson Brain Imaging Centre and Academic Department of Neurosurgery, Addenbrooke's Hospital, Cambridge, England. pawanminhas@hotmail.com
authors.forename: Pawan S
authors.initials: PS
authors.lastname: Minhas
authors.forename: David K
authors.initials: DK
authors.lastname: Menon
authors.forename: Piotr
authors.initials: P
authors.lastname: Smielewski
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kirkpatrick
authors.forename: John C
authors.initials: JC
authors.lastname: Clark
authors.forename: John D
authors.initials: JD
authors.lastname: Pickard
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000503:physiopathology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D023261:Glasgow Outcome Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D009422:Nervous System Diseases / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D015996:Survival Rate; D014055:Tomography, Emission-Computed; D017585:Ultrasonography, Doppler, Transcranial; D020301:Vasospasm, Intracranial / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*