Ultrasound diagnostic apparatus

An ultrasound diagnostic apparatus, comprising:

• a unit which transmits and receives ultrasonic waves with respect to a three-dimensional space within a living organism to thereby obtain original volume data;
• a generation unit which removes noise from the original volume data to thereby generate bloodstream volume data containing velocity information within a bloodstream;
• and
• an image-forming unit which forms a three-dimensional bloodstream image by reference to the bloodstream volume data,
• wherein the bloodstream volume data comprises a plurality of voxel values, each voxel value being a velocity value having a positive or negative sign;
• the image-forming unit comprises:
• a setting unit which, after the generation of the bloodstream volume data by the generation unit sets a plurality of rays radiating from a viewpoint, which is set at an arbitrary position, with respect to the bloodstream volume data generated by the generating unit, the plurality of rays being associated with addresses on a two-dimensional screen;
• a searching unit which searches a first peak value from a search start point as the viewpoint on each of the plurality of rays by sequentially referring to an absolute value of each of the voxel values;
• and
• a unit which forms the three-dimensional bloodstream image, in which the positive and negative signs are represented with different colors, by mapping, on the two-dimensional screen, the plurality of voxel values corresponding to a plurality of the first peak values searched on the plurality of rays,
• the searching unit executes a search process which sequentially refers to the absolute value of a voxel value of each voxel from the search start point on each of the plurality of rays, and in the search process, when the referred absolute value of the voxel value first increases, and then decreases after reaching a peak value corresponding to a vertex of a first hill, the peak value corresponding to the vertex of the first hill is determined as the first peak value, and
• on the three-dimensional bloodstream image, in a portion in which images of a plurality of bloodstreams cross each other, the image of the bloodstream closest to the viewpoint is preferentially represented.