Patent ID: 6068598
Filing Date: 2000-05-30
Classification: A61B,G01S

Abstract:
A method for estimating a Doppler angle between a direction of an ultrasound transmit beam and an axis of a blood vessel, comprising the steps of:displaying an ultrasound image of said blood vessel;storing a frame of image parameter values from which said ultrasound image was derived, said image parameter values corresponding to respective pixels in said image;placing a graphic representing a range gate overlying said blood vessel in said image;identifying a center point of a search area corresponding to a point lying within said range gate, wherein the image parameter values in said frame corresponding to pixels in a center area surrounding said center point have a lower average image parameter value than the image parameter values in said frame corresponding to pixels in other areas within said search area;searching for a respective edge point outward along each one of a multiplicity of radial lines extending from said center point and angularly spaced over a predetermined angular range within said search area, said searches being conducted from said center point to a predetermined distance along each radial line in accordance with a search algorithm;applying a line-fit algorithm to at least some of the edge points within each of a plurality of segments of said search area, said line-fit algorithm generating respective pluralities of vessel slope estimates and goodness-of-fit measurements;identifying a best goodness-of-fit measurement from amongst said plurality of goodness-of-fit measurements;combining the vessel slope estimate corresponding to said best goodness-of-fit measurement with other vessel slope estimates corresponding to other goodness-of-fit measurements not exceeding some difference relative to said best goodness-of-fit measurement; anddetermining said Doppler angle as a function of said combined vessel slope and said transmit beam direction.