Abstract: A method of locating a contour of a structure in an image by processing said image including the structure is provided. A starting set of digital data representative of the image including the structure is taken, the structure in said image having annotated on it from three to ten landmark positions. A statistical model of said structure to the landmark positions annotated on the image is fitted and an initial estimate of the contour of the structure made. Using grey level information derived from points adjacent the estimated contour the contour boundary is iteratively moved to produce a final estimate of the contour of the structure.