An image processing apparatus comprises obtainment means (1010) for obtaining a contrast material-enhanced image of an object； first region extraction means (1040) for extracting a first region representing a first anatomical portion of the object from the image； estimation means (1060) for estimating a state of the image concerning a temporal change in gray level from the first region； and second region extraction means (1070) for extracting a second region representing a second anatomical portion of the object from the image based on an estimation result obtained by the estimation means.
