1. An image processing apparatus, comprising: an index computing unit configured to compute motion functional indices of a particular organ from volume data of a subject including said particular organ; a polar map generating unit configured to generate a polar map by developing said indices on a polar coordinate system; an image generating unit configured to generate, from said volume data, an image related to a structure of one of said particular organ and a peripheral organ developed on the polar coordinate system; a fusing unit configured to fuses said image into said polar map; and a display unit configured to displays a polar map fused with said image.