title: Comparison of carotid artery blood velocity measurements by vector and standard Doppler approaches.
abstract: Although severely affected by the angle dependency, carotid artery peak systolic velocity measurements are widely used for assessment of stenosis. In this study, blood peak systolic velocities in the common and internal carotid arteries of both healthy volunteers and patients with internal carotid artery stenosis were measured by two vector Doppler (VD) methods and compared with measurements obtained with the conventional spectral Doppler approach. Although the two VD techniques were completely different (using the transmission of focused beams and plane waves, respectively), the measurement results indicate that these techniques are nearly equivalent. The peak systolic velocities measured in 22 healthy common carotid arteries by the two VD techniques were very close (according to Bland-Altman analysis, the average difference was 3.2%, with limits of agreement of ± 8.6%). Application of Bland-Altman analysis to comparison of either VD technique with the spectral Doppler method provided a 21%-25% average difference with ± 13%-15% limits of agreement. Analysis of the results obtained from 15 internal carotid arteries led to similar conclusions, indicating significant overestimation of peak systolic velocity with the spectral Doppler method. Inter- and intra-operator repeatability measurements performed in a group of 8 healthy volunteers provided equivalent results for all of the methods (coefficients of variability in the range 2.7%-6.9%), even though the sonographers were not familiar with the VD methods. The results of this study suggest that the introduction of vector Doppler methods in commercial machines may finally be considered mature and capable of overcoming the angle-dependent overestimation typical of the standard spectral Doppler approach.
authors.affiliation: Department of Information Engineering, Università degli Studi di Firenze, Florence, Italy. Electronic address: piero.tortoli@unifi.it.
authors.forename: Piero
authors.initials: P
authors.lastname: Tortoli
authors.affiliation: Department of Information Engineering, Università degli Studi di Firenze, Florence, Italy; CREATIS, Université de Lyon 1, CNRS UMR 5220, INSERM U1044, INSA, Lyon, France.
authors.forename: Matteo
authors.initials: M
authors.lastname: Lenge
authors.affiliation: Heart and Vessels Department, AOU Careggi, Florence, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Righi
authors.affiliation: Heart and Vessels Department, AOU Careggi, Florence, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Ciuti
authors.affiliation: CREATIS, Université de Lyon 1, CNRS UMR 5220, INSERM U1044, INSA, Lyon, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Liebgott
authors.affiliation: Department of Information Engineering, Università degli Studi di Firenze, Florence, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ricci
mesh_terms: D001783:Blood Flow Velocity; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler / Q000379:methods*
keywords: Angle independent; Blood velocity estimation; Carotid artery hemodynamics; Real-time velocity measurement; Spectral Doppler; Vector Doppler