1. A medical image diagnosis apparatus comprising: a designating unit that designates an imaging range of a subject from a two-dimensional projection image for designation of the imaging range; a specifying unit that specifies a specific seed spot on the two-dimensional projection image; a scanning control unit that performs scanning for generating a three-dimensional medical image of the subject on the basis of the imaging range designated by the designating unit after the specific seed spot has been specified on the projection image; a region determining unit that projects the seed spot onto the three-dimensional medical image to determine a three-dimensional target region from the three-dimensional medical image obtained by the scanning on the basis of the specific seed spot specified on the projection image; and a detection unit that detects a candidate for an abnormal part in the three-dimensional target region.