title: Ophthalmic artery flow direction on color flow duplex imaging is highly specific for severe carotid stenosis.
abstract: OBJECTIVE
  Collateral flow patterns are important risk factors for brain ischemia in the presence of internal carotid artery (ICA) stenosis or occlusion. Ophthalmic artery (OA) flow reversal, routinely studied by transcranial Doppler sonography, is an important marker for high-grade ICA stenosis or occlusion. The authors sought to define the value of assessing OA flow direction with color flow duplex ultrasonography (CDUS) in the setting of significant ICA disease.
  
  
  METHODS
  Of all patients having routine carotid ultrasound in the neurosonology laboratory between July 1995 and November 2000, 152 had both carotid and orbital (OA flow direction by reduced power orbital CDUS) examinations as well as angiographic confirmation of stenosis to which North American Symptomatic Carotid Endarterectomy Trial criteria could be applied. Degree of angiographic stenosis in these 152 patients (304 arteries) was correlated with OA flow direction.
  
  
  RESULTS
  Of 304 arteries, 101 had greater than 80% stenosis by angiogram. In 56 of these 101 arteries with high-grade stenosis or occlusion, the ipsilateral OA was reversed; however, OA flow direction was never reversed ipsilateral to arteries with less than 80% stenosis (sensitivity 55%, specificity 100%, negative predictive value 82%, and positive predictive value 100% for OA flow reversal as a marker of high-grade carotid lesions).
  
  
  CONCLUSIONS
  OA flow direction is easily studied with CDUS. Reversed OA flow direction is highly specific (100%) for severe ipsilateral ICA stenosis or occlusion, with excellent positive predictive value, moderate negative predictive value, and limited sensitivity. OA flow reversal is not only quite specific for severe ICA disease, which may be helpful if the carotid CDUS is difficult or inadequate, but may also provide additional hemodynamic insights (i.e., the inadequacy of other collateral channels such as the anterior communicating artery). OA evaluation can provide important hemodynamic information and should be included as part of carotid CDUS if there is any evidence of ICA stenosis or occlusion.
authors.affiliation: Department of Neurology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA. preynold@wfubmc.edu
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Reynolds
authors.forename: Jason P
authors.initials: JP
authors.lastname: Greenberg
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Lien
authors.forename: Dana C
authors.initials: DC
authors.lastname: Meads
authors.forename: Lawrence G
authors.initials: LG
authors.lastname: Myers
authors.forename: Charles H
authors.initials: CH
authors.lastname: Tegeler
mesh_terms: D001783:Blood Flow Velocity; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D002533:Cerebral Angiography; D016009:Chi-Square Distribution; D003097:Collateral Circulation; D006801:Humans; D016013:Likelihood Functions; D009880:Ophthalmic Artery / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D012307:Risk Factors; D012680:Sensitivity and Specificity; D018615:Ultrasonography, Doppler, Color