1. A method of generating a dissection curve between a first and a second object in a volume image, the method executed at least in part on a computer, comprising: accessing volume image data of a subject as a set of image slices; identifying a region of the volume image data that comprises at least the first and second objects; defining one starting point in the volume image data for the dissection curve according to a geometric primitive; from the one starting point, identifying a plurality of successive dissection curve points that are points of minimum intensity in successive image slices; and displaying the dissection curve that connects the identified plurality of successive dissection curve points.