1. A non-invasive method for analyzing coronary arteries of a living subject without iodine contrast material being injected into the subject, the method comprising: providing a plurality of internal images of the heart, each image comprising image elements indicative of properties of corresponding heart structures; identifying boundaries of the heart within the plurality of heart images, the boundaries defining a heart volume; defining surface coordinates of the heart volume; defining a shell volume at the surface of the heart volume, the shell volume having a thickness greater than the diameter of coronary arteries; identifying the coronary arteries within the shell volume by using pixel intensity values and expected shape values of the coronary arteries; and displaying the images of the coronary arteries.