1. A medical image processing apparatus comprising processing circuitry configured to: implement registration on a medical image and each of a plurality of reference images; perform deformation on the medical image based on a result of the registration by the registration circuitry; set a first region of interest on the deformed medical image; set on at least two of the plurality of reference images, a second region of interest corresponding to the first region of interest; and retrieve from the reference images on which the second region of interest is set, a reference image similar to an image in the first region of interest.