1. A method for identifying calcification portions in a dual energy computerized tomography (CT) contrast agent enhanced scanning image, the method comprising the steps of: filtering pixels in the dual energy CT contrast agent enhanced scanning image to acquire pixels to be grouped; grouping the pixels to be grouped into a plurality of pixel groups according to positions of the pixels to be grouped; material-decomposing the pixels in each of said pixel groups; and identifying pixels in one of the material-decomposed groups corresponding to a calcification portions in the scan image, wherein the step of identifying the pixels in one of the material-decomposed groups corresponding to the calcification portions comprises: establishing a decomposition value scatter diagram indicative of the relationship among the material-decomposing results of each pixel in the pixel group according to the result of the material-decomposing for pixels in each pixel group; and determining whether the pixels correspond to the calcification portions according to the positions of pixels of the pixel group in the decomposition value scatter diagram, wherein the pixel group comprises pixels with CT values outside a designated region.