title: Transcranial Doppler grading criteria for basilar artery vasospasm.
abstract: OBJECTIVE
  Transcranial Doppler (TCD) criteria for basilar artery (BA) vasospasm are poorly defined, and grading criteria for vertebrobasilar vasospasm are unavailable. The purpose of the present study was to define TCD grading criteria for BA vasospasm on the basis of the absolute flow velocities and the intracranial to extracranial flow velocity ratios for the posterior circulation, and to improve the sensitivity and specificity of TCD for diagnosis of BA vasospasm.
  
  
  METHODS
  One hundred twenty-three patients with aneurysmal subarachnoid hemorrhage underwent 144 cerebral arteriograms with views of the BA during the acute phase of vasospasm (Days 3-14 after hemorrhage). BA diameters were measured and compared with diameters obtained from baseline arteriograms. Both BA and extracranial vertebral artery flow velocities were measured by TCD within 4 hours before the arteriogram.
  
  
  RESULTS
  The velocity ratio between the BA and the extracranial vertebral arteries (VA) strongly correlated with the degree of BA narrowing (r2 = 0.648; P < 0.0001). A ratio higher than 2.0 was associated with 73% sensitivity and 80% specificity for BA vasospasm. A ratio higher than 2.5 with BA velocity greater than 85 cm/s was associated with 86% sensitivity and 97% specificity for BA narrowing of more than 25%. A BA/VA ratio higher than 3.0 with BA velocities higher than 85 cm/s was associated with 92% sensitivity and 97% specificity for BA narrowing of more than 50%.
  
  
  CONCLUSIONS
  The BA/VA ratio improves the sensitivity and specificity of TCD detection of BA vasospasm. On the basis of the BA/VA ratio and BA mean velocities, we suggest new TCD grading criteria for BA vasospasm.
authors.affiliation: Department of Neurosurgery Rambam (Maimonides) Medical Center, Haifa, Israel. sviri@u.washington.edu
authors.forename: Gill E
authors.initials: GE
authors.lastname: Sviri
authors.forename: Basavaraj
authors.initials: B
authors.lastname: Ghodke
authors.forename: Gavin W
authors.initials: GW
authors.lastname: Britz
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Douville
authors.forename: David R
authors.initials: DR
authors.lastname: Haynor
authors.forename: Ali H
authors.initials: AH
authors.lastname: Mesiwala
authors.forename: Arthur M
authors.initials: AM
authors.lastname: Lam
authors.forename: David W
authors.initials: DW
authors.lastname: Newell
mesh_terms: D000328:Adult; D001488:Basilar Artery / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001921:Brain / Q000098:blood supply / Q000503:physiopathology; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods* / Q000592:standards; D020301:Vasospasm, Intracranial / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014711:Vertebral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D014715:Vertebrobasilar Insufficiency / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology