PROBLEM TO BE SOLVED: To provide an image processing apparatus capable of improving accuracy in region extraction from three-dimensional image data, and to provide an image processing method and a medical image diagnostic apparatus.SOLUTION: An image processing apparatus includes a first extraction part and a second extraction part. The first extraction part extracts a first region containing a structure of an extraction object from three-dimensional image data. The second extraction part extracts the region of the structure by dividing the first region into a plurality of small regions on the basis of the degree of similarity of the feature amount of a voxel and a positional relation and extracting the small regions included in the structure from the plurality of small regions on the basis of the degree of similarity and the positional relation to the second region as a region other than the first region in the three-dimensional image data.SELECTED DRAWING: Figure 4COPYRIGHT: (C)2016,JPO&INPIT
