title: Reproducibility of two 3-D ultrasound carotid plaque quantification methods.
abstract: Compared with single 2-D images, emerging 3-D ultrasound technologies hold the promise of reducing variability and increasing sensitivity in the quantification of carotid plaques for individual cardiovascular risk stratification. Inter- and intra-observer agreement between a manual, cross-sectional, 2-D freehand sweep and a mechanical 3-D ultrasound investigation of 62 carotid artery plaques is reported with intra-class correlation coefficients (with 95% confidence intervals). Inter-observer agreement was 0.60 (0.29-0.77) for the freehand method and 0.89 (0.83-0.93) for the mechanical 3-D acquisition. The use of semi-automated computerized planimetric measurements of plaque burden has high intra-observer repeatability, but is vulnerable to systematic inter-observer differences. For the 2-D freehand sweep, a considerable contribution to variation is introduced by the scanning procedure itself, that is, the lack of controlled motion along the third dimension. Future implementation of 3-D ultrasound quantification in large-scale studies of inter-individual cardiovascular risk assessment seems justified using the methods described.
authors.affiliation: Department of Vascular Surgery, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. Electronic address: martin.graebe@regionh.dk.
authors.forename: Martin
authors.initials: M
authors.lastname: Græbe
authors.affiliation: Philips Healthcare, Bothell, Washington, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Entrekin
authors.affiliation: Philips Healthcare, Bothell, Washington, USA.
authors.forename: Antoine
authors.initials: A
authors.lastname: Collet-Billon
authors.affiliation: Philips Healthcare, Bothell, Washington, USA.
authors.forename: Gerard
authors.initials: G
authors.lastname: Harrison
authors.affiliation: Department of Vascular Surgery, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Sillesen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography
keywords: Agreement; Carotid plaque; Intra-class correlation coefficient; Quantification; Reproducibility; Three-dimensional; Ultrasound; Volume