title: Carotid artery occlusion: positive predictive value of duplex sonography compared with arteriography.
abstract: OBJECTIVE
  Duplex ultrasonography is an accurate, noninvasive method for diagnosing, characterizing, and classifying atherosclerotic stenoses of the extracranial carotid artery system. To date, however, no large series has studied the predictive value of duplex sonography in the diagnosis of carotid artery occlusion, an important consideration, given the marked difference in clinical treatment between patients with high-grade stenosis (surgical therapy) and those with occlusive disease (nonsurgical therapy).
  
  
  METHODS
  We retrospectively reviewed 158 patients with 174 occluded carotid artery segments (examined over a 6 1/2-year period) to determine the predicative value of duplex sonography in differentiating carotid artery occlusion from high-grade stenosis.
  
  
  RESULTS
  All patients had arteriographic correlation. Duplex ultrasonography had a positive predictive value of 92.5% (7.5% false-positive rate; 95% confidence interval, 3.6% to 11.4%) in establishing a diagnosis of carotid artery occlusion. Further analysis revealed no significant improvement in the false-positive rate with the addition of color Doppler flow imaging to high-resolution B-mode scanning and pulsed Doppler spectral analysis. Predictive value increased to 96.7% (95% confidence interval, 90.7% to 99.3%) over the last 2 years of the study, a statistically significant improvement.
  
  
  CONCLUSIONS
  We believe that duplex ultrasonography is an acceptably accurate method for diagnosing carotid arterial occlusion in most patients. Arteriography should be reserved for patients with symptoms who are surgical candidates to identify those who may still have a surgically correctable high-grade stenosis.
authors.affiliation: Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN 55905.
authors.forename: J D
authors.initials: JD
authors.lastname: Kirsch
authors.forename: L R
authors.initials: LR
authors.lastname: Wagner
authors.forename: E M
authors.initials: EM
authors.lastname: James
authors.forename: J W
authors.initials: JW
authors.lastname: Charboneau
authors.forename: D A
authors.initials: DA
authors.lastname: Nichols
authors.forename: F B
authors.initials: FB
authors.lastname: Meyer
authors.forename: J W
authors.initials: JW
authors.lastname: Hallett
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000453:epidemiology; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D005260:Female; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000000981:diagnostic imaging* / Q000453:epidemiology; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D014465:Ultrasonics; D014463:Ultrasonography