title: Changes in cerebral blood flow and vasoreactivity in response to acetazolamide in patients with transient global amnesia.
abstract: OBJECTIVE
  Previous reports about changes in cerebral blood flow (CBF) in transient global amnesia disclosed decreased flow in some parts of the brain. However, CBF analyses in most reports were qualitative but not quantitative. The purpose of this study was to determine changes in CBF in transient global amnesia.
  
  
  METHODS
  The CBF was measured and the vasoreactive response to acetazolamide was evaluated in six patients with transient global amnesia using technetium-99m hexamethylpropylene amine oxime single-photon emission computed tomography (SPECT). The CBF was measured during an attack in two patients and soon after an attack in the other four. About one month later, CBF was re-evaluated in each patient.
  
  
  RESULTS
  Two patients examined during an attack and one patient examined five hours after an attack had increased blood flow in the occipital cortex and cerebellum. Three patients examined at six to 10 hours after an attack had decreased blood flow in the thalamus, cerebellum, or putamen. These abnormalities of blood flow almost disappeared in all patients one month after onset. The vasodilatory response to acetazolamide, which was evaluated initially using SPECT, was poor in areas of increased blood flow. By the second evaluation of CBF with acetazolamide, the vasodilatory response had returned to normal.
  
  
  CONCLUSIONS
  In a patient with transient global amnesia, CBF increased in the vertebrobasilar territory during the attack and decreased afterwards. The vasodilatory response to acetazolamide may be impaired in the parts of the brain with increased blood flow. It is suggested that transient global amnesia is distinct from migraine but may share the same underlying mechanism.
authors.affiliation: Department of Neurology, Tonami General Hospital, Toyama, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sakashita
authors.forename: M
authors.initials: M
authors.lastname: Kanai
authors.forename: T
authors.initials: T
authors.lastname: Sugimoto
authors.forename: S
authors.initials: S
authors.lastname: Taki
authors.forename: M
authors.initials: M
authors.lastname: Takamori
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology* / Q000627:therapeutic use*; D000647:Amnesia / Q000188:drug therapy*; D001488:Basilar Artery / Q000502:physiology; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use*; D002531:Cerebellum / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000187:drug effects*; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon; D014711:Vertebral Artery / Q000502:physiology
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D019690:Technetium Tc 99m Exametazime; D000086:Acetazolamide