An anatomical structure is segmented from images generated in an anatomical scan. A user input device is configured for manually identifying two or more seed points on a plurality of the images. An image processor is configured to identify an optimal path through seed points on the plurality of images with a graph search. The optimal path between corresponding seed points on different images defines a boundary contour, and the anatomical structure includes two or more boundary contour. The image processor is further configured to interpolate the boundary contours over a three-dimensional volume using cardinal splines.