A medical image diagnostic apparatus includes storage circuitry and processing circuitry. The storage circuitry is configured to store three-dimensional medical image data that is obtained by imaging a subject. The processing circuitry is configured to set a region of attention in each of medical images of the three-dimensional medical image data corresponding to at least two directions. The processing circuitry is configured to calculate, based on the regions of attention, a region of interest in the three-dimensional medical image data on the subject. The processing circuitry is configured to calculate, based on voxel values of the region of interest, a parameter value relating to image processing on a medical image that is generated from the three-dimensional medical image data. The processing circuitry is configured to generate a display image by performing rendering processing on the basis of the three-dimensional medical image data and the parameter value.
