title: Impact of cerebral microcirculatory changes on cerebral blood flow during cerebral vasospasm after aneurysmal subarachnoid hemorrhage.
abstract: OBJECTIVE
  Cerebral microcirculatory changes during cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) are still controversial and uncertain. The aim of this study was to investigate the changes of cerebral microcirculation during cerebral vasospasm and to clarify the roles of microcirculatory disturbances in cerebral ischemia by measuring cerebral circulation time (CCT) and regional cerebral blood flow (rCBF).
  
  
  METHODS
  In 24 cases with aneurysmal SAH, rCBF studies by single-photon emission CT and digital subtraction angiography (DSA) were performed on the same day between 5 and 7 days after SAH and/or within 4 hours after the onset of delayed ischemic neurological deficits. CCT was obtained by analyzing the time-density curve of the contrast media on DSA images and was divided into proximal CCT, which was the circulation time through the extraparenchymal large arteries, and peripheral CCT, which was the circulation time through the intraparenchymal small vessels. They were analyzed in association with rCBF and angiographic vasospasm.
  
  
  RESULTS
  Severe angiographic vasospasm statistically decreased rCBF, and correlation between the degree of angiographic vasospasm and rCBF was seen (r=0.429, P=0.0006). Peripheral CCT showed strong inverse correlation with rCBF (r=-0.767, P<0.0001). Even in none/mild or moderate angiographic vasospasm, prolonged peripheral CCT was clearly associated with decreased rCBF.
  
  
  CONCLUSIONS
  In addition to the marked luminal narrowing of large arteries detected as severe angiographic vasospasm, microcirculatory changes detected as prolonged peripheral CCT affected cerebral ischemia during cerebral vasospasm. These results suggested that impaired autoregulatory vasodilation or decreased luminal caliber in intraparenchymal vessels may take part in cerebral ischemia during cerebral vasospasm.
authors.affiliation: Department of Neurosurgery, Hirosaki University School of Medicine, Hirosaki, Japan. ohkuma@cc.hirosaki-u.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Ohkuma
authors.forename: H
authors.initials: H
authors.lastname: Manabe
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005625:Frontal Lobe / Q000098:blood supply; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D007457:Iodine Radioisotopes; D008297:Male; D008833:Microcirculation / Q000502:physiology; D008875:Middle Aged; D009778:Occipital Lobe / Q000098:blood supply; D010296:Parietal Lobe / Q000098:blood supply; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome; D014661:Vasoconstriction / Q000502:physiology*
chemical_list: D007457:Iodine Radioisotopes