title: Extracranial internal carotid artery occlusion: the role of common carotid artery volume flow.
abstract: OBJECTIVE
  Quantitative measurement of blood flow volume in the common carotid artery (CCA) is now possible using the color velocity imaging quantification (CVI-Q) ultrasound technique. The aim of this study was to evaluate the cerebral hemodynamic effects of unilateral internal carotid artery (ICA) occlusion on CCA blood flow volumes (FVs) using CVI-Q.
  
  
  METHODS
  Records of ultrasound studies in our neurosonology laboratory were retrospectively reviewed to identify patients with unilateral ICA occlusions who at a minimum received both a routine color duplex carotid ultrasound examination and quantitative measurement of FV in the CCA, bilaterally, using the CVI-Q method. A total of 71 patients met criteria and were included in the cohort. A side to side comparison was performed for FV, peak systolic velocities (PSV), end-diastolic velocities (EDV), and resistance indices (RIs) in the CCA. Results correlated with any other available data such as flow direction in the ophthalmic artery and the presence of intracranial collateralization.
  
  
  RESULTS
  The FV, PSV, and EDV were significantly reduced, and the RI was significantly increased in the CCA on the side of the occlusion. A subgroup analysis in patients who also had an examination of the ophthalmic (n = 61) and the intracranial arteries of the Circle of Willis (n = 50), showed significantly higher FV in the CCA on the side of the occlusion if there was also reversed flow in the ophthalmic artery on the side of the occlusion (344 +/- 144 ml/min versus 169 +/- 53 ml/min).
  
  
  CONCLUSIONS
  Quantitative FV measurement using CVI-Q ultrasound can identify clear alterations in volume flow, collateral pathways, and cerebral hemodynamics in patients with unilateral ICA occlusion. It is a complementary tool, providing additional objective information about the cerebral hemodynamic effects of ICA occlusion that goes beyond what is available using routine flow velocity data.
authors.affiliation: Department of Neurology (I), Chang Gung Memorial Hospital, 123 Ta-Pei Road, Niao-Sung Hsiang, Kaohsiung Hsien, Taiwan, ROC. tengyeowtan@yahoo.com
authors.forename: Teng-Yeow
authors.initials: TY
authors.lastname: Tan
authors.forename: Ulf
authors.initials: U
authors.lastname: Schminke
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Lien
authors.forename: B Martin
authors.initials: BM
authors.lastname: Eicke
authors.forename: Charles H
authors.initials: CH
authors.lastname: Tegeler
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003097:Collateral Circulation; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging / Q000503:physiopathology; D012189:Retrospective Studies; D018615:Ultrasonography, Doppler, Color