1. A method for measuring calcification in an aorta of a living body, comprising: providing a three-dimensional volumetric image of the body, the image comprising a plurality of axial slices, each axial slice comprising voxels indicative of densities of corresponding to body structures; locating a vertebral body in an axial slice of the plurality of axial slices; locating an exterior cortical bone margin of the vertebral body; automatically defining a search region of interest (ROI) anterior to the exterior cortical bone margin, the search ROI encompassing the aorta; identifying calcium voxels within the search ROI encompassing the aorta having x-ray attenuation values above a predetermined threshold value; and providing a quantitative measure of calcium.