Abstract: A method of estimating the volume flow in a vessel utilizing ultrasound techniques including the steps of imaging the vessel utilizing an ultrasonic transducer array so as to produce fluid velocity information for the vessel, the plane formed by the beams emitted by the transducers having a direction which is offset from an axis of the vessel such that the beam plane forms an elliptical section within the vessel, and utilizing the velocity information for points within the vessel and the elliptical section to calculate a mean velocity for the fluid flow through the elliptical section. The improvement of the volume flow estimation is achieved by utilizing average velocity information and Doppler signal power, and mean velocity calculation based on a weighted summation of the velocity values a multiple measurement points with weighting factors determined by the Doppler signal power at the measurement points.