A method and apparatus are provided for finding a fluid conduit of a human body within a set of images collected over a portion of a cardiac cycle and where each image of the set of images is formed by a plurality of image elements. The method includes the steps of selecting a reference image element within the fluid conduit from the plurality of image elements, determining a velocity profile of each of the image elements over the cardiac cycle and identifying the fluid conduit by correlating the velocity profile of the reference element with velocity profiles at least some of the other image elements.