title: B-mode estimate of carotid stenosis: planimetric measurements complement the velocity estimate of internal carotid stenosis.
abstract: OBJECTIVE
  Velocity criteria for diagnosis of carotid stenosis are subject to flow phenomenon such as contralateral stenosis or occlusion. Duplex tri-axial diameter and cross sectional area measurements are potentially more accurate because they are anatomic.
  
  
  METHODS
  As part of a prospective study on triplanar ultrasound carotid stenosis measurements, 30 consecutive patients were studied by 3 independent operators to assess variability of the technique. PSV and EDV were recorded at the common and internal carotid arteries and Duplex B-mode long-axis and diameter views were obtained using color and/or power Doppler. Cross-sectional area (CSAS), minimal luminal diameter (MLD), and triaxial diameter measurements, based on the NASCET criteria were performed at the narrowest lumen.
  
  
  RESULTS
  The CSAS, MLD and triaxial diameter measurements were not significantly different in the 3 measurements and that was true for the 3 operators (ANOVA, P=0.1 for both). There were 4 patients where the velocity measurements differed by one stenosis grade, when compared to diameter. The triaxial diameter stenosis correlated well with the percent area reduction for all three measurements. Other than having a very good linear relationship (R2=0.95, R2=0.96, R2=0.93). The MLD was reduced with increasing grades of stenosis and provided a clear separation between the 50-69% and 80-99% grades with only a small overlap in the 70-79% grade.
  
  
  CONCLUSIONS
  The present analysis demonstrates that CSAS and triaxial diameter can be performed by experienced investigators with low variability and good reproducibility. Velocity and planimetric measurements are complimentary in the assessment of carotid artery stenosis.
authors.affiliation: Section of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA.
authors.forename: K
authors.initials: K
authors.lastname: Bekelis
authors.forename: N
authors.initials: N
authors.lastname: Labropoulos
authors.forename: P
authors.initials: P
authors.lastname: Pappas
authors.forename: A
authors.initials: A
authors.lastname: Gasparis
mesh_terms: D000704:Analysis of Variance; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006439:Hemodynamics; D006801:Humans; D009513:New Hampshire; D009518:New York; D015588:Observer Variation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D018615:Ultrasonography, Doppler, Color; D018616:Ultrasonography, Doppler, Duplex