Methods for the improved interactive segmentation of medical image slice data using a computer include the novel combination of the well-known live wire and snakes methods. The improved techniques automatically insert new anchor points for each medical image slice that is processed. The improved methods called iterative live wire and live snakes result in a segmentation process that is faster, more accurate, and requires less operator interaction than the previous methods while still allowing an operator to make adjustments to the segmentation as the process moves from one image slice to the next.