Ultrasound diagnostic apparatus, ultrasound image-processing apparatus and ultrasound image-processing method

The ultrasound diagnostic apparatus of an embodiment: acquires first and second volume data by scanning a three-dimensional region of a subject that comprises a lumen with ultrasonic waves using the B-mode and a blood flow-detecting mode; establishes a viewpoint in the lumen and a plurality of sight lines having said viewpoint as a reference point; determines the sight lines, among the multiple sight lines, on which data corresponding to the endoluminal region, extraluminal tissue data, and blood flow data corresponding to extraluminal blood flow are disposed; at least controls the value of a parameter associated with each voxel of the tissue data present on the determined sight lines; and using the first volume data containing the voxels with controlled parameter values and the second volume data, generates and displays a virtual endoscopic image from the viewpoint.