One of problems with the current cardiac CT imaging is the banding artifacts, i.e., horizontal shifts in multiplanar reformatted (MPR) or three-dimensional (3-D) images. In this work, we propose a novel gating method that does not rely on electro-cardiogram but uses the similarity of image pixel values of heart images. Moreover, the proposed method optimizes the cardiac phase on a local basis. Evaluations with 10 patient data sets showed the substantial reduction of banding artifacts as well as the improved consistency in anatomical structures.