title: Improved objective selection of power Doppler wall-filter cut-off velocity for accurate vascular quantification.
abstract: The wall-filter selection curve method is proposed to objectively identify a cut-off velocity that minimizes artifacts in power Doppler images. A selection curve, which is constructed by plotting the color pixel density (CPD) as a function of the cut-off velocity, exhibits characteristic intervals hypothesized to include the optimum cut-off velocity. This article presents an improved implementation of the method that automatically detects characteristic intervals in a selection curve and selects an operating point cut-off velocity along a characteristic interval. The method is applied to subregions within the Doppler image to adapt the cut-off velocity to local variations in vascularity. The method's performance is evaluated in 30-MHz power Doppler images of a four-vessel flow phantom. At high (>5 mm/s) flow velocities, qualitative improvements in vessel delineation are achieved and the CPD in the resulting images is accurate to within 3% of the vascular volume fraction of the phantom.
authors.affiliation: Biomedical Engineering Graduate Program, Western University, London, Ontario, Canada.
authors.forename: Mai
authors.initials: M
authors.lastname: Elfarnawany
authors.forename: Stephen Z
authors.initials: SZ
authors.lastname: Pinter
authors.forename: James C
authors.initials: JC
authors.lastname: Lacefield
mesh_terms: D000465:Algorithms; D000818:Animals; D015150:Echocardiography, Doppler / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D055806:Microvessels / Q000000981:diagnostic imaging*; D010363:Pattern Recognition, Automated / Q000379:methods*; D019047:Phantoms, Imaging