title: Simplified ultrasound protocol for the exclusion of clinically significant carotid artery stenosis.
abstract: OBJECTIVE
  To evaluate a simplified ultrasound protocol for the exclusion of clinically significant carotid artery stenosis for screening purposes.
  
  
  METHODS
  A total of 9,493 carotid arteries in 4,748 persons underwent carotid ultrasound examination. Most subjects were 65-year-old men attending screening for abdominal aortic aneurysm. The presence of a stenosis on B-mode and/or a mosaic pattern in post-stenotic areas on colour Doppler and maximum peak systolic velocity (PSV) in the internal carotid artery (ICA) were recorded. A carotid stenosis was defined as The North American Symptomatic Carotid Endarterectomy Trial (NASCET) >20% and a significant stenosis as NASCET >50%. The kappa (κ) statistic was used to assess agreement between methods. Sensitivity, specificity, positive predictive (PPV), and negative predictive (NPV) values were calculated for the greyscale/mosaic method compared to conventional assessment by means of PSV measurement.
  
  
  RESULTS
  An ICA stenosis was found in 121 (1.3%) arteries; 82 (0.9%) were graded 20%-49%, 16 (0.2%) were 50%-69%, and 23 (0.2%) were 70%-99%. Eighteen (0.2%) arteries were occluded. Overall, the greyscale/mosaic protocol showed a moderate agreement with ICA PSV measurements for the detection of carotid artery stenosis, κ = 0.455. The sensitivity, specificity, PPV, and NPV for detection of >20% ICA stenosis were 91% (95% CI 0.84-0.95), 97% (0.97-0.98), 31% (0.26-0.36), and 97% (0.97-0.97), respectively. The corresponding figures for >50% stenosis were 90% (0.83-0.95), 97% (0.97-0.98), 11% (0.08-0.15), and 100% (0.99-1.00).
  
  
  CONCLUSIONS
  Compared with PSV measurements, the simplified greyscale/mosaic protocol had a high negative predictive value for detection of >50% carotid stenosis, suggesting that it may be suitable as a screening method to exclude significant disease.
authors.affiliation: a Department of Surgical Sciences , Section of Vascular Surgery, Uppsala University , Uppsala , Sweden ;|b Department of Surgery , NU Hospital Organization , Trollhättan , Sweden.
authors.forename: Dominika
authors.initials: D
authors.lastname: Högberg
authors.affiliation: a Department of Surgical Sciences , Section of Vascular Surgery, Uppsala University , Uppsala , Sweden ;
authors.forename: Demosthenes
authors.initials: D
authors.lastname: Dellagrammaticas
authors.affiliation: a Department of Surgical Sciences , Section of Vascular Surgery, Uppsala University , Uppsala , Sweden ;
authors.forename: Björn
authors.initials: B
authors.lastname: Kragsterman
authors.affiliation: a Department of Surgical Sciences , Section of Vascular Surgery, Uppsala University , Uppsala , Sweden ;
authors.forename: Martin
authors.initials: M
authors.lastname: Björck
authors.affiliation: a Department of Surgical Sciences , Section of Vascular Surgery, Uppsala University , Uppsala , Sweden ;
authors.forename: Anders
authors.initials: A
authors.lastname: Wanhainen
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging*; D001783:Blood Flow Velocity; D002309:Cardiology / Q000379:methods* / Q000592:standards; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*; D018608:Ultrasonography, Doppler
keywords: Carotid stenosis; screening; ultrasound