1. A method for the automatic delineation or extraction of a first region which is the cardiac region of interest (CROI) adjacent to a chest wall in computer tomographic angiograpy (CTA) images, the method comprising the steps of: determining the chest wall; determining a second region where the first region is attached to the chest wall; determining an aorta in the first region; initializing a closed contour around the first region; and optimizing a shape of the closed contour.