1. A method of identifying a border of a vascular object, comprising: acquiring multiple sets of blood-vessel data, each set corresponding to an image of a vascular object; using a set of blood-vessel data to approximate a border on an image of said vascular object; identifying at least one control point on said border; extrapolating said at least one control point to at least one other set of blood-vessel data, creating at least one other control point on at least one other image; using said at least one other control point to approximate at least one other border on said at least one other image; and adjusting said at least one other border in accordance with at least a frequency factor.