title: The evaluation of intra- and extra-cranial circulation in subclavian steal syndrome.
abstract: OBJECTIVE
  To compare the efficacy of transcranial Doppler ultrasound (TCD) and digital subtraction angiography (DSA) in identifying the clinical and hemodynamic relationship between intra- and extra-cranial circulation and subclavian steal syndrome.
  
  
  METHODS
  Sixteen patients were collected. The intra- and extra-cranial arteries were insonated with Doppler ultrasound. DSA and brain CT were performed in all patients. The relationship between the grade of arterial stenosis showing in DSA and the flow direction showing in TCD was studied.
  
  
  RESULTS
  TCD showed reversal flow of the vertebrobasilar artery in 13 patients, normal flow in 3, which was influenced obviously by fist-clenching. In the hyperemia test, the flow velocity and the direction changed significantly in all patients. The steal phenomenon of the middle cerebral artery (MCA) was coincident with that of the arterial cerebral artery (ACA) in 2 cases. Stenosis of MCA or ACA was found in 5 cases (31%). Nine patients were treated with arterial bypass or angioplasty. TCD was performed during the follow-up.
  
  
  CONCLUSIONS
  Reversal flow of the vertebral artery may occur in rest or only in exercise, depending on the grade of subclavian arterial stenosis. Hyperemia test is the most sensitive index. It is necessary to monitor blood flow in the MCA and basilar artery in hyperemia test. The coexistence of intra- and extra-cranial arterial stenosis is common.
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Beijing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
authors.forename: S
authors.initials: S
authors.lastname: Gao
authors.forename: B
authors.initials: B
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013349:Subclavian Steal Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017585:Ultrasonography, Doppler, Transcranial