title: Simultaneous quantification of flow and tissue velocities based on multi-angle plane wave imaging.
abstract: A quantitative angle-independent 2-D modality for flow and tissue imaging based on multi-angle plane wave acquisition was evaluated. Simulations of realistic flow in a carotid artery bifurcation were used to assess the accuracy of the vector Doppler (VD) technique. Reduction in root mean square deviation from 27 cm/s to 6 cm/s and 7 cm/s to 2 cm/s was found for the lateral (vx) and axial (vz) velocity components, respectively, when the ensemble size was increased from 8 to 50. Simulations of a Couette flow phantom (vmax = 2.7 cm/s) gave promising results for imaging of slowly moving tissue, with root mean square deviation of 4.4 mm/s and 1.6 mm/s for the x- and z-components, respectively. A packet acquisition scheme providing both B-mode and vector Doppler RF data was implemented on a research scanner, and beamforming and further post-processing was done offline. In vivo results of healthy volunteers were in accordance with simulations and gave promising results for flow and tissue vector velocity imaging. The technique was also tested in patients with carotid artery disease. Using the high ensemble vector Doppler technique, blood flow through stenoses and secondary flow patterns were better visualized than in ordinary color Doppler. Additionally, the full velocity spectrum could be obtained retrospectively for arbitrary points in the image.
authors.affiliation: Department of Circulation and Medical Imaging, Norwegian University of Science and Technology, Trondheim, Norway. ingvild.k.ekroll@ntnu.no
authors.forename: Ingvild Kinn
authors.initials: IK
authors.lastname: Ekroll
authors.forename: Abigail
authors.initials: A
authors.lastname: Swillens
authors.forename: Patrick
authors.initials: P
authors.lastname: Segers
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Dahl
authors.forename: Hans
authors.initials: H
authors.lastname: Torp
authors.forename: Lasse
authors.initials: L
authors.lastname: Lovstakken
mesh_terms: D000368:Aged; D002339:Carotid Arteries / Q000000981:diagnostic imaging* / Q000502:physiology; D003198:Computer Simulation; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D019047:Phantoms, Imaging; D012039:Regional Blood Flow / Q000502:physiology*; D012044:Regression Analysis; D018608:Ultrasonography, Doppler / Q000379:methods*